# Interest group forums > Electrical Contracting Industry Forum >  Saturday at home, installing an inverter

## AndyD

This was my first Saturday at home for almost as long as I can remember so I thought I'd get something useful done around the house.

I've installed several inverters recently for various clients and I picked a 3kW one up for myself last week along with 4 x 240Ah deep cycle batteries. Up until recently I've been using a 6KVA genny to allow me to continue working in my home office during the load shedding periods but now we've been getting power outages between 8 and 10pm and the genny is a pain to set up in the dark and it's also a bit noisy and smokey for that time in an evening so I decided something semi-permanent and more subtle was required.

I'm kinda lucky with my office because there's two sockets that were part of the original electrical installation and there's another 8 sockets that are installed surface and in trunking which are spurred off the original circuit. It sounds like a lot of sockets but they're all low load for PC's, monitors, routers, 2 smallish servers, a couple of laptops, several small chargers, an illuminated magnifier and a small domestic PABX phone thingy....oh and a small bar fridge.  

I used a clamp meter with a max hold facility on the incoming circuit over a period of a few days and the absolute max current draw was 3.18 Amps and this was short duration ie miliseconds. I also wanted to run my TV and media PC which was another 1.23Amps and finally I decided that I couldn't live without my coffee machine which is supposedly 1.8kW but actually weighed in at 6.4 Amps @ 219v when I measured it.

Total current requirement was 10.81A which meant I required a 3kW inverter.

The coffee machine is obviously a heavyweight compared to the office and TV requirements but it's a very intermittant load, over a period of an hour the pressure switch kicks in and out to supply the element and the actual heating period was only around 14 minutes so the battery drain isn't as bad as I thought it might be. The total power consumption per hour works out to 1.13kW so for a 2 1/2 hour loadshed I need 2.852kWh.

The battery supply is 24V so to supply the max load (10.18A @ 230V) I'd be drawing around 104Amps at 24V so some seriously large battery cabling is needed. Over a 2 1/2 hour running time I would be draining the batteries at 47Ah x 2.5 =  117.7Ah. This is approx a 50% drain which is within the manufacturers spec and projected battery life expectancy is around 500 cycles at these figures. 

Okay, enough calculations, back to my day off at home.

----------

smitty (15-May-15)

----------


## AndyD

First job was to clear some space, make a hole in the counter, install some trunking and screw the inverter to the wall with 200mm clear around the sides for airflow. Easy peasy!!





The trunking s a bit ratty looking because I only had a second hand piece kicking around at home so I made do with what I had.

Next was find an old piece of scaffold plank and clean it up a bit with a sander and use it as a base to place the 4 x batteries on top of. This is probably optional but it helps to be able to move the batteries all together by sliding the plank to allow cleaning behind them in future.



Next I installed the two 35mm² battery wires starting at the inverter end. A 100Amp fuse was used at the final battery terminal and link wires were made to connect the batteries together. 




If you're ever dealing with battery installations I'd caution that the potential fault currents are enormous. Always fuse a battery installation because if there's ever a fault there's a very high likelyhood it will result in a fire and always take great care when using spanners and other tools that you never contact other terminals by accident because the results will be spectacular. Finally never leave the tops of the batteries exposed because someone will at some time accidentally short them out by placing something metallic on top of them.  




The main supply cable to my original office sockets was removed and diverted into the inverter as the incoming supply and a new cable was installed from the inverter back to the sockets.



The wiring is very straight forward but the terminal blocks in the inverter were very awkward and it took several attempts to get good terminations.

----------


## AndyD

Next I tested the circuit to avoid any nasty surprises and switched the inverter on. It ran immediately in back-up mode supplying the office sockets from the back-up batteries and when I restored power to the office circuit at my DB it immediately went into charging cycle.

The inverter is seemless in the case of power fail, it takes 5mS to switch from Eskom power to battery power so all computers and other appliances keep running normally. All the inverter settings out of the box were fine except for the low battery cut-off voltage which was a bit on the low side; I'd rather not cycle my batteries as deep as they had it set because their life expectancy takes a knock so with only one small adjustment necessary I was finished for the day by 2pm.

The inverter can also have a string of solar PV panels connected to it which is nice for future if the power situation deteriorates for example. The charging ability of the inverter is 50Amps so I could also add a second string of 4 batteries or even a third string in future if I wanted to extend the running time. I've got a very nice North facing low pitched roof so six panels would make the system completely off-grid except for maybe a few days in mid-winter.



Sure enough we had load shedding this evening and everything was as per plan. I ran a temporary extension lead for my TV and we watched a movie and had coffee, wi-fi and internet access for the full 2 hours.

Tomorrow I've just got to install the permanent cable for the TV and coffee machine back-up supply.

I'm also using the batteries to run some 12VDC back-up lighting. In every room I've installed a small 10watt floodlight with a retrofitted pullswitch. They're supplied by 2 x 12VDC circuits directly from the batteries and they're more than bright enough for functional lighting.



I've also got to install a short supply from my newly fitted batteries to power these two lighting circuits.

If you've installed any back-up power systems of your own, please don't be shy, feel free to post about them below hopefully with some accompanying photos. It's always interesting to see different approaches to the same problem.

----------

mikilianis (17-May-16)

----------


## julies

Wow Andy, Nice work.. and all in one day :-) 
So what does all of this cost (inverter, battery, cabling) ? What brands are you using ?
I would like to do something like this, but then the issue of COC comes to mind

----------


## AndyD

Thanks Julies, it was more like 5 hours solid installation time and would have been less if I wasn't working on my own and with secondhand bits and pieces. We do install this kinda thing for a living so I'd allow a full day if you're not familiar with this type of kit.

I spent another couple of hours today to properly install the cable to the TV at the other end of the house and to run the 12VDC supply to hook into the existing lighting circuits so I'm finished for now and no longer need to live like a troglodyte for two hours a day, at least three days a week.

The cost is a tricky one for several reasons, firstly I had most of the installation materials already to hand from stock. Secondly I pay dealer prices for inverters and batteries so I'm not going to workout my cost because it won't be a fair reflection of what you could expect to pay.

If you were to order such a system as a customer I'd expect the inverter would be around R10K. Obviously this inverter is a pure sine output plus it's a 50Amp intelligent PWM battery charger and it's a solar PV controller with monitoring software all in one so it's considerably more expensive than a cheap inferior camping type inverter. 

The batteries are also not cheap, for a single 230Ah battery of recognised brand you're going to pay in excess of R2200.00 so for a similar 3kW setup to run a smallish office for 2-3 hours as outlined above you're in for >R20K I'm afraid and that's before there's any installation labour and sundries which would also vary depending on how much cabling etc is required for your particular installation.

I suppose compared to a decent Honda 3KVA self start, silent generator with a nice built-in AVR the price is in the same ballpark. Both the generator and inverter options have their own advantages but for a small office environment I'd chose the inverter any day. Generators aren't seemless unless you add a UPS into the equation and inverters don't carry the ongoing maintenance and fuel costs that a generator does. The inverter is also scaleable so it will adapt better to changes in requirements in the future. On the flip side an inverter setup isn't portable, the batteries do require some very light maintenance every few months (which you can do yourself) and the batteries will need replacing in 5-7 years if load shedding continues at the present rate.

As for compliance, the system I've installed will be compliant once I've finished tidying it up with a battery cover, some labelling etc and I can issue a Coc for it if I need one. There's no reason an inverter or a generator can't be installed to be compliant to the electrical installation regs if a competant installer is used.

----------


## bergie

nice Andy.i wish i had your energy. 
i would also like to know which brand you use and what supplier?
i have been looking at ACDC but i know they are not shy to sell cr@p.
i want to start installing for customers.
what is the advantage of an inverter over a UPS with external batteries. i'm guessing the easier connection to solar.
what battery charger are you using?

----------


## bergie

ok ,after reading your post again,i see the inverter has a built in battery charger.
it looks as if the batteries are connected in series.are they 6v batteries as you say you have 24 volts in total?

----------


## AndyD

> nice Andy.i wish i had your energy.


Lol, my get up and go....got up and went many years ago  :Wink: 




> i would also like to know which brand you use and what supplier?
> i have been looking at ACDC but i know they are not shy to sell cr@p.
> i want to start installing for customers.


ACDC do have some lines that are not my favourites but they also have some lines that are very respectable, guess it's a matter of knowing which is which. They have started selling the Victron range recently which are absolutely superb pieces of equipment. We were installing Victron stuff about 6 or 7 years ago and I've loved it ever since. The only downside is the cost, for a 3kW Victron Multiplus you're going to part with about 18-20K just for the inverter but like I say you do get what you pay for in this case.
Send me a PM with the type of system you're thinking about and I'll give you suppliers details.




> what is the advantage of an inverter over a UPS with external batteries. i'm guessing the easier connection to solar.
> what battery charger are you using?


 Battery charger is built into the inverter. Scaleability and the ability to handle multiple power sources is one advantage. The inverters can be supplied by a combination of wind turbine, generator, solar PV and Eskom power for example and different power sources can be set in order for priority of use. You'll struggle to find a UPS with a 50A PWM intelligent battery charger built into it. With some inverters you can link them together to provide a single larger output or even link 3 x single phase inverters to provide a 3-phase output so they're a lot more flexible than a UPS.




> ok ,after reading your post again,i see the inverter has a built in battery charger.
> it looks as if the batteries are connected in series.are they 6v batteries as you say you have 24 volts in total?


Yes, built-in charger and the batteries I used are 4 x 6v deep cycle in series to give 24VDC. At present I'm tapping off the middle of the battery bank and both ends to give me 2 x 12VDC supplies for the lighting circuits but this isn't ideal because they're unlikely to be perfectly balanced loads so I'm going to fit a 24-12 DC converter across the entire bank sometime next week so the lighting load is pulled evenly from all the batteries.

----------


## bergie

thanks andy. i will pm you.
so once you have your solar panels all you will need is the grid tie inverter. i cant see it being long before we can feed back into eskom.

----------


## HR Solutions

Andy I need one in Cape Town.  Please give me a price installed ?

----------


## AndyD

> thanks andy. i will pm you.
> so once you have your solar panels all you will need is the grid tie inverter. i cant see it being long before we can feed back into eskom.


Until Eskom comes up with a feed-in-tariff I won't be exporting power into their grid and I suspect they've got quite a few ducks to get into rows before they can handle full scale importing and exporting from domestic solar PV.

I think it's fair to point out that this kind of system is purely a convenience thing, it's not designed to make money or even save money, in fact there's a considerable capital outlay with zero return for nothing more than reducing the inconvenience caused by the regular load shedding.

There is potential to add solar PV panels to this system but without a feed in tariff being available from government it's a no win sum financially, it would take decades probably to pay back the capital outlay with the energy savings and when you also consider the life expectancy of the batteries and other factors there's a very good chance you'll never make anywhere near break-even.




> Andy I need one in Cape Town.  Please give me a price installed ?


I've sent you a PM HR.

----------


## bergie

i see there are quite a few inverter installations on the golf estates. the inverter is connected to the electric golf cart. then there is no need to buy expensive batteries. obviously if you use the golf cart then you dont have back up at that time.the lead unplugs from the golf cart ,the inverter would be switched off and the changeover switch would be on eskom. can anybody see any reason not to do it like that?

----------


## HR Solutions

There are batteries in the golf cart

----------


## Justloadit

The only problem I can see, is after a couple of hours, you no longer can use the golf cart and will require to carry your bag on your back and walk. :Smile:

----------


## bones

lo Andy 

ok if i dont wire the system into the building 
use trunking and dont touch the main power
at all will it be ok to do this in my bedroom 

just to keep the basics going 500watts max
i know a guy that sells truck batteries will 
they work? 24volts batteries 

my thinking is to add sun panels to the mix 
and perhaps adding a smoke detector 

if i move i want to take it all with me

----------


## AndyD

> i see there are quite a few inverter installations on the golf estates. the inverter is connected to the electric golf cart. then there is no need to buy expensive batteries. obviously if you use the golf cart then you dont have back up at that time.the lead unplugs from the golf cart ,the inverter would be switched off and the changeover switch would be on eskom. can anybody see any reason not to do it like that?


I've also seen golf carts used as a DC power supply for a domestic back-up inverter. The golf cart I saw also had a few PV panels on its roof, I don't see any reason it shouldn't be done if you happen to have one kicking around.




> lo Andy 
> 
> ok if i dont wire the system into the building 
> use trunking and dont touch the main power
> at all will it be ok to do this in my bedroom 
> 
> just to keep the basics going 500watts max
> i know a guy that sells truck batteries will 
> they work? 24volts batteries 
> ...


I'm sure it would be fine to do this in your bedroom. Just wire it up with trailing leads, same as you would install a UPS, it will be easy to dismantle and take with you if you relocate. 

Truck batteries aren't ideal, same as car batteries they're not designed to be cycled as deep as an inverter will drain them. If a car or truck battery is used as it's designed where it's drained less than 10% when starting the vehicle then immediately recharged back to full then they will last 5 years usually. I've seen whole banks of car batteries used on inverter systems where they're being drained 60-70% and they've been scrap after a couple of months only. Rather go with better rated deep cycle batteries, they're more expensive to buy but it will be a lot cheaper in the long run. 

Adding solar panels is possible but it's expensive and you'll probably not recover the outlay with the energy savings they'll give you just on a back-up inverter. PV panels will also make the installation a lot more complex especially if your inverter isn't designed to have them connected directly into it. Maybe in the future PV panels would be a viable alternative to adding extra batteries if the load shedding times become much longer than they are now but I'd suggest keeping things simple will be the cheapest route for the occasional blackouts we're getting at the moment.

----------

bergie (26-Mar-15)

----------


## bones

i will look into it thanks

----------


## bones

lo Andy 

ave look at this from "low price power alternative




> Attachment 5442
> 
>  i have no idea if this is right or not but 
> the bit that gets me is the solar panel 
> bit if this right then what stops the 
> inverter from pulling power directly from 
> the charger and solar panel 
> 
> both the charger controller and the 
> ...

----------


## AndyD

No, you can leave the charger connected. The inverter will draw power from both the batteries and the charger when its running but that's fine, the charger will only supply whatever is being generated by the PV panels and the remainder of the requirement will be drawn from the batteries until they become drained, at which point the voltage will drop to a point where the inverter will shut down.

----------

bones (27-Mar-15)

----------


## AndyD

Well I'm very pleased with my setup, it performed beyond expectations yesterday evening when we had load shedding between 6pm and 8.30pm. All the back-up lights throught the house were running from 6.30pm onwards, all the office stuff like PC's, printers, routers, phones and laptops were running, the entertanment PC and the TV in the lounge was running, I used the coffee machine a couple of times and we cooked supper using the microwave and sandwich toaster for at least 20 minutes. 

At the end of load shedding the batteries were cycled to less than 40% of their available power which was very encouraging. The recharge time was 5 hours so in theory we can run with 3 lots of load shedding per day on the setup I've got as long as the outages are spaced 4 or 5 hours apart.

Given that hopefully were're unlikely to encounter anything like 3 loadshedding periods in a day and given the ease with which the system coped for a 2.5 hour power outage I'm going to extend it this weekend to cover the fridge and freezer, the outdoor LED lighting which is 4x 10W floodlights, some homemade fairylights on the stoep and also the ceiling fan circuit which supplies a fan in every room throughout the house.

----------

bones (27-Mar-15)

----------


## bones

thankyou Andy now i can get 
started on getting parts   :Big Grin:

----------


## HR Solutions

> thankyou Andy now i can get 
> started on getting parts





> got a e-mail today from the person setting up 
> the move send me a bunch of stuff to fill in 
> and asked that i get started on my passport 
> next month he will be setting up possible 
> employers to speak to us and get a feel what 
> is expected of us and what we need so on 
> 
> it is actually happening sh_t i never thought i 
> would go but here i am doing exactly that 
> ...


I thought you were packing up and leaving SA ?

----------


## bones

> I thought you were packing up and leaving SA ?


can take up to 15 months in the 
meantime i have a business to 
run so that i can pay for stuff 

my wife does graphic design and 
takes her work home she does 
freehand and pc sketch so she 
needs her lightbox pc scanner 
and all the rest working we cant 
run a generator all the time

----------


## Tonye

Hi Andy,

Nice job.

Just completed an inverter installation for a client


Moved essential circuits from main DB to a Mini DB with Earth Leakage unit and a changeover switch.
Used a 24 v 2400 VA inverter with 2x 105amphour deep cycle batteries.

----------


## AndyD

Nice looking installation, your trunking is neater than mine  :Wink: 

Looks like a lot of essential circuits in the back-up sub-DB.

----------


## Tonye

> Nice looking installation, your trunking is neater than mine 
> 
> Looks like a lot of essential circuits in the back-up sub-DB.


Thanks Andy,
the trunking is quite expensive but comes with all sorts of inside, outside bends & end caps.
Saves on having to mitre bends.
I have moved quite a few circuits. 3 light circuits & 5 plug circuits.
Client currently has 70x 50w down lights. This is being changed to 4 watt LEDs.
The plug circuits are feeding the following
Study ( small PC, Modem router, inkjet printer & a laptop.
Living room ( Led Tv, Dstv decoder & 2x table lamps)
Dining Room ( two table lamps)
Formal lounge ( 1x standing lamp, 1 table lamp)
Main bedroom ( 2x table lamps, 1 x led Tv)

The client is aware that when running in inverter mode, he cannot run everything simultaneously
but still has the convenience of being able to run most of his plug & light circuits.
Obviously when running from mains, there are no restrictions.
The system has been designed to allow an upgrade to a larger system if required.
When running essential items the changeover can be left in inverter mode to supply uninterrupted power supply
in the event of power failure.
Fridges, pool pump, air cons, microwave, washing m/c, dishwasher, geyser, stove etc have been left on Main DB.
I was fortunate that the circuits I moved did not include the above.
I was going to do a total changeover at the main DB, where the client turns off high current items prior changeover
but the Main DB is three phase and did not want to fiddle whith a 4 pole changeover with bridged connection on inverter mode. ( not sure if this would pass a COC)
One problem I had was when tracing neutrals for the lighting circuits, I found one light circuit that even after disconnecting all the neutrals still powered lights in certain lights. Obviously a major neutral to earth fault. Two of these lights are large chandeliers which can be reached easily.
I have informed the client to contact the electrician who issued the COC to rectify the problem.

----------


## HR Solutions

> Hi Andy,
> 
> Nice job.
> 
> Just completed an inverter installation for a client
> 
> 
> 
> 
> ...


What does something like this cost ?

----------


## Tonye

> What does something like this cost ?


Total cost for this installation R22000.00 excl

----------


## AndyD

> Thanks Andy,
> the trunking is quite expensive but comes with all sorts of inside, outside bends & end caps.
> Saves on having to mitre bends.


My trunking was recycled second-hand  :Frown:  It was all I could find at the time and the installation was in my own office so I wasn't too worried.



> I have moved quite a few circuits. 3 light circuits & 5 plug circuits.
> Client currently has 70x 50w down lights. This is being changed to 4 watt LEDs.


Sounds sensible. Trying to accomodate 50w halogen downlights would be pointless and expensive. Every installation is different, you installed your inverter at the main DB and separated 8 circuits out into a back-up Sub DB, I installed my inverter very similar to installing a UPS where it supplies only my office circuit. The other supplies to the kitchen and lounge are run as temporary extension leads. This was just to keep the complexity down and to allow it to evolve easily for future, if it had been a customer installation we'd have also installed a subDB specifically for back-up and marshalled all the apporopriate circuit into there.     




> One problem I had was when tracing neutrals for the lighting circuits, I found one light circuit that even after disconnecting all the neutrals still powered lights in certain lights. Obviously a major neutral to earth fault. Two of these lights are large chandeliers which can be reached easily.
> I have informed the client to contact the electrician who issued the COC to rectify the problem.


 Yeah, pre-testing the circuits beforehand is critical. The lighting circuit probably has a borrowed or crossed neutral with another circuit, if it was an N-E insulation fault it should have shown up under normal testing if a CoC has been recently issued.




> Total cost for this installation R22000.00 excl


 I think your pricing is pretty good. I'm not sure what inverter you've used but I know if I was quoting to install the setup I outlined at the beginning of the thread it would be around R26 - 28K including labour. You've installed a subDB and changeover switch but I've got extra battery capacity and a larger inverter so it's swings and roundabouts.

----------


## blackknight72

Hello Andy,

I am considering installing a 3KW inverter system at my home. I must say I have found your inputs in the forum very educative and thank you for the same.

My initial considerations were Honda Inverter Generator Eu30i costing around R20000 versus an inverter. I abandoned the idea since it is not available locally here in East London and also due to issues pertaining to maintanance. I am planning to connect ( a fridge, tv, dstv, router, lights / all led and rarely a printer) I thought my power requirements are similar to your's or probably less.In your post you mentioned that a system like your's will cost more or less in the same price range. I received a quote for Axpert 3KVA unit with 4 trojan batteries including installation for R50000. The Axpert unit was quoted R17000 and the batteries (Trojan deep cycle cells) R20000 (R5000x4).  This is beyond my budget at the moment.

Are you able to suggest any reliable units as well as batteries that can bring down the costs involved. I came across Maximus batteries which were quoted R1500 but I  am not sure how reliable they are or the life expectancy for the same.

I am currently faced an occasional 1 or 2 hour long power cut. Hence after going through another post from you I was also considering voltronic unit 2kva to start off with and add another one as time goes by depending on my requirement. however I am unable to get any information on the particular unit or its price. I am also wondering if it would be a very expensive exercise to add more units.

I will greatly appreciate your feedback in the above matter.

----------


## AndyD

> In your post you mentioned that a system like your's will cost more or less in the same price range. I received a quote for Axpert 3KVA unit with 4 trojan batteries including installation for R50000. The Axpert unit was quoted R17000 and the batteries (Trojan deep cycle cells) R20000 (R5000x4).  This is beyond my budget at the moment.


 The prices are very high, I can only suggest you get some more quotes. There was a brand new Axpert 3KW inverter being sold here which is sold now but it should give you an indication of the ballpark price you should be looking at. I charge customers around R2200.00 each for the Trojan 6v deep cycle batteries I'm not sure why you're getting quoted R5K each unless they're a much higher specification battery.




> Are you able to suggest any reliable units as well as batteries that can bring down the costs involved. I came across Maximus batteries which were quoted R1500 but I  am not sure how reliable they are or the life expectancy for the same.


 I'm not familiar with the Maximus batteres but I think your original spec with the Axpert inverter and Trojan batteries was probably spot on, like I say I'd do some more investigating for better prices if I were you.




> I am currently faced an occasional 1 or 2 hour long power cut. Hence after going through another post from you I was also considering voltronic unit 2kva to start off with and add another one as time goes by depending on my requirement. however I am unable to get any information on the particular unit or its price. I am also wondering if it would be a very expensive exercise to add more units.


 Voltronic are the Taiwanese company that produce the Axpert range of inverters mentioned above. I'm not really understanding your question here. Some of the Axpert inverters are scaleable whereby you can connect two of them together and they produce a single output that's double the power of a single inverter. Not all are capable of this so you need to read the specs of the different models.

----------


## blackknight72

Thank you very much for your prompt response.

I shall certainly investigate around the prices. I was under the impression that Voltronic was a different brand which is more expensive than Axpert. Do you by any chance happen to sell any of these inverters?

I am just wondering if it would be possible for me to buy the batteries from you. I am not certain how much it will cost to courier them to East London.

----------


## bergie

those prices are very expensive . i sell the 5kva axpert for cheaper than the 3kva you have being quoted on. i install as well. i use the bosch 105AH 12 volt batteries. 4 in series.
the 5kva model can be paralleled up to 6 inverters and has a built in powerful mppt solar charger. 
i am however looking for enclosed battery cases for 4 batteries. i have been making my own.







> Thank you very much for your prompt response.
> 
> I shall certainly investigate around the prices. I was under the impression that Voltronic was a different brand which is more expensive than Axpert. Do you by any chance happen to sell any of these inverters?
> 
> I am just wondering if it would be possible for me to buy the batteries from you. I am not certain how much it will cost to courier them to East London.

----------

blackknight72 (04-May-15)

----------


## AndyD

> I was under the impression that Voltronic was a different brand which is more expensive than Axpert.


 I'm wondering if you're getting confused with 'V*ic*tronic' who are better known nowadays as 'Victron'. 

Victron are a superior product in my humble opinion, if you look at the multiplus range and compare the raw specifications with other makes of inverter you'll see what I mean. Unfortunately they're considerably more expensive which often makes them a hard sell in the domestic and small business market even though you do get what you pay for. 

The V*ol*tronic website is here http://www.voltronicpower.com/ . If you look under the 'Inverter & AVR' menu you'll see the Axpert ranges.






> Do you by any chance happen to sell any of these inverters?


 We're primarily designing and installing complete systems but if you send me a PM with your requirements including model number I'll happily give you a quote for supply only. If you're unsure which model suits your requirements I'll try to help you find the best option.    





> I am just wondering if it would be possible for me to buy the batteries from you. I am not certain how much it will cost to courier them to East London.


 Again I'll happily give you a quote if you give me the specifics of your preferred batteries ie voltage, cycle rating and capacity in Ah etc. If you have your own courier I'll liase with them otherwise I'll investigate transport options from my side and you'd just pay whatever costs are incurred.

----------

blackknight72 (04-May-15)

----------


## blackknight72

> I'm wondering if you're getting confused with 'V*ic*tronic' who are better known nowadays as 'Victron'. 
> 
> Victron are a superior product in my humble opinion, if you look at the multiplus range and compare the raw specifications with other makes of inverter you'll see what I mean. Unfortunately they're considerably more expensive which often makes them a hard sell in the domestic and small business market even though you do get what you pay for. 
> 
> The V*ol*tronic website is here http://www.voltronicpower.com/ . If you look under the 'Inverter & AVR' menu you'll see the Axpert ranges.
> 
> 
> 
>  We're primarily designing and installing complete systems but if you send me a PM with your requirements including model number I'll happily give you a quote for supply only. If you're unsure which model suits your requirements I'll try to help you find the best option.    
> ...


Thank you Andy! I will check the facts once again with the installer and see if he willing to provide another quote. If he sticks to the same quote I shall get the units and batteries from you.  I will have to find someone who is willing to do the installation for me in that case.

Indeed I was confused between the brands victron and voltronic. I was referring to Victron.

I would like your opinion on my judgment regarding a 3KW inverter based on my needs.

My requirements are the following 

Led down lights ( all dimmable 5w) 20 units
TV+ dstv
Inkjet printer
refrigerator 300W
Motor for garage door
CFL 6x10W

Do you think 3KW would be an overkill in this scenario?

Thank you!

----------


## blackknight72

> those prices are very expensive . i sell the 5kva axpert for cheaper than the 3kva you have being quoted on. i install as well. i use the bosch 105AH 12 volt batteries. 4 in series.
> the 5kva model can be paralleled up to 6 inverters and has a built in powerful mppt solar charger. 
> i am however looking for enclosed battery cases for 4 batteries. i have been making my own.


Thank you bergie,please see my response below.

----------


## blackknight72

> Thank you bergie,please see my response below.


Thank you for your feedback. I received another quote today from yet another installer, R34000 for installing a 1KW system ( includes 4 trojan 240Ah batteries and 1KW inverter)This simply highlights the value of forums like this and inputs given by people like yourself when it comes to taking an informed decision. Certainly inverter installation in this part of the country is a lucrative business.

----------


## AndyD

> Indeed I was confused between the brands victron and voltronic. I was referring to Victron.


 Lol, I had a sneaky feeling you were. I've installed Victron units as far back as 6 or 7 years ago in the marine sector and we've never had a failure to date. I rate them very highly but alas they're often outside of the budget.




> I would like your opinion on my judgment regarding a 3KW inverter based on my needs.
> 
> My requirements are the following 
> 
> Led down lights ( all dimmable 5w) 20 units
> TV+ dstv
> Inkjet printer
> refrigerator 300W
> Motor for garage door
> ...


 When establishing your load requirements there's no substitute for using an RMS clamp meter to actually test the current draw of each appliance whilst it's running. It also helps if the clamp meter has a maximum hold facility which retains the maximum current draw over a period of time. We always check the real-life power requirements before specifying an inverter, the difference between the current stated on the appliance and the actual current draw as measured in real life can be as much as 50%. Make yourself up a test lead as shown below and use it to supply each appliance in turn whilst you perform load current tests. If you don't have a clamp meter it's well worth begging, borrowing, stealing or buying one.



You may also be able to apply some sensible 'diversity', for example it's highly unlikely you'd be opening the garage door at the precise time you're printing a document. On the other side of things it's possible that your fridge which is a motor load could have a momentary start current of maybe 1.5KW just for a fraction of a second when the compressor starts running.

----------


## bergie

a calculated guess. at least a 2 kw . 3kw if you can afford it . i wouldnt recommend a 1kw at all. if you run these inverters full load all the time it wont last long.
i will be getting a shipment of 5 kva 22 amp axpert inverters in a few weeks. it will be very reasonably priced.

----------


## Justloadit

I have just the instrument to measure power with the necessary plug and socket

I also have a plug attachment to connect a bayonet socket and a E28 socket, so that you can show the consumption of a incandescent lamp against a LED lamp.

My dealer price is R1,650.00 excluding VAT from my office.

----------


## Justloadit

Here a picture of it for those not too interested in reading the brochure

----------

bones (07-May-15)

----------


## AndyD

> ...........i wouldnt recommend a 1kw at all. if you run these inverters full load all the time it wont last long.........


This was one of the reasons I installed this unit in my home office, I wanted to put it under a test regime before I offered them as an option to customers. I've performed a series of marginal and substantial overload tests under varying ambient temperatures on it whilst monitoring internal component temperatures to see how it performed. I've run it under highly inductive and highly capacitive loads and I've also run some controlled short circuit tests to check disconnect times of OCPD's etc and fault current handling abilities of the output components and internal safety systems.

----------


## bergie

andy, is it the 1kw axpert inverter you are testing? for blacknights purposes it probably would be under rated

----------


## AndyD

It's the 3kW unit same as Blacknight was looking at for his installation.

----------


## IMHO

Andy, need your help! 

As you know I run a guesthouse and I am looking at getting away slowly from Eskom. I am changing my geysers to gas as they pack-up. Done two so far, plenty to go. Stove is gas now as well. The next area I need to tackle is my laundry. I used the clamp tester method as you showed and here is the results. I would love to put the laundry on solar. I use the tumble dryers a lot, as it is the only way to get our towels soft. The washing machines also work hard. Ironing is 3 irons for about 2 hours a day, but lets work on 4 hours a day.

Appliance  Iron x 3
H/day 4 hours
Amps peak 7.8A
Amps normal 0
They switch on and off, so it is either peak or off, They switch on for a minute or two to get to temp and then switch on and of every few seconds, say 30sec intervals.

Appliance  Tumble Dryer1 (10kg)
H/day 4 hours
Amps peak 13A on switch on
Amps normal settles to under 8A
Peak at 13 amp very short. Then stays on 7.8A about for the duration.

Appliance  Tumble Dryer2 (5kg)
H/day 2 hours but very seldom uses it. Just on very rare occasions. 
Amps peak A on switch on
Amps normal settles to under A
Peak at  amp very short. Then stays on A about for the duration.

Appliance Washing Machine Whirlpool
H/day 4 hours (actual 3 but work on 4)
Amps peak 5A on spin
Amps normal settles to under 3A

Appliance  SpeedQueen
H/day 4 hours (actual 3 but work on 4)
Amps peak 8A on spin
Amps normal settles to under 5A

My aim would be to get these appliances completely off grid, with solar. So I need to know the inverter size and specs, batt capacity and solar panels to do the charging. Rainy or cloudy days, I will have to revert back to Eskom. Or will it be cost effective to have battery capacity to last 4 days? I would also need something to tell me what capacity is left. (Like a petrol gauge, hehe)

----------


## IMHO

Another thing to consider. Whasing is done in the mornings and ironing in the afternoon, with tumble drying between washing and Ironing.

Lets say 8am to 10am washing
11am - 1 pm tumble drying
2pm-4pm Ironing.

Above is a tipical day. As you can see, I overstated some durations above. I omitted tumble dryer 2's specs above, as I do not have it. It can be ignored.

----------


## AndyD

A couple of observations to start with, the washing machine current draws are lower than I would have expected for commercial machines, are they being supplied with pre-heated water? If they're heating their own water I think their maximum load should be higher durng the heating cycle than during the spin cycle.

Secondly the tumble dryer with it's short peak of 13A,is this the motor start current or is the duration of this peak longer than a second or two?

Also can you define the overlap between the washing and drying and ironing where two of the operations are taking place simultaneously or even all three operations?

----------


## IMHO

> are they being supplied with pre-heated water?


No, we wash cold water only. I only measured spin cycle, due to this reason. I can use hot water, but that is supplied via the hot water tap, from the geyser. I will test again when they use the machine again. BTW, it is not commercial machines, it is the normal household big Whirlpool and SpeedQueen machines, +-12kg




> Secondly the tumble dryer with it's short peak of 13A, is this the motor start current or is the duration of this peak longer than a second or two?


No, a second or two. If you do not watch closely, you will miss it.




> Also can you define the overlap between the washing and drying and ironing where two of the operations are taking place simultaneously or even all three opera


I cross questioned the staff and my wife on this today. Seems like there is no overlapping. Washing is done early morning when they are still cleaning rooms. Then when the tumble drying start, it is to uncomfortable in the room to do ironing. I realize that saves me a lot. I will just have to make it law that there is to be no overlapping, even as an exception, and install an alarm type buzzer that warns when the threshold is reached or tripping out at a safe amp-age cutoff?

----------


## IMHO

The bulk of the laundry, namely the sheets, is send to someone else to wash and Iron. We do only a little bit of that, if we get our planning wrong. Our biggest loads is towels and pillow cases, plus clothing.

PS. I have just been informed we do a fair amount of sheets ourselves now as well, as the laundry in town can not keep up. But we stick to the hours mentioned.

----------


## bergie

i think the top loaders should all have a separate hot water connection and the front loaders have a built in element,with no hot water connection. i speak under correction.

----------


## IMHO

You are right bergie, it is top loaders.

----------


## wynn

I am waiting for the battery that will be produced by young master Musk and the PV cells to be produced by a factory being constructed in the ELIDZ.
Right now the estimate is that one can completely go off the grid with 10Kw 24/7 for about R80,000.oo and that this price will come down in the future as competition in the market increases. Or what?

----------


## Justloadit

Elon still has to build his factory, expected completion date 2017.

----------


## AndyD

> Elon still has to build his factory, expected completion date 2017.


 That's still several years before Medupi is likely to be on-line  :Wink:

----------


## wynn

Here is a link to an article in the M&G about just this battery

http://mg.co.za/article/2015-05-11-p...into-a-battery

----------


## AndyD

The issue with existing batteries is  that they suck.

He's not wrong, storing power is inefficient and expensive but it's a necessary evil with load shedding and it's often cheaper and more efficient (and more neighbour-friendly) than the other option which is small generators.

----------


## blackknight72

Hello again, Today I found an Axpert 3KW MKS plus 24 volt system in a local shop with a price tag of  R7000 Inc Vat. I checked with my contractor if it is okay to purchase that instead of the 48 volt system he chose for my system which was R2500 more expensive.  He was vehemently opposed to it and was concerned that it will put a 'lot of strain' in the system 24 volt inverter. The best way he could explain the difference was by making a comparison between performance of  a C 180 merc vs C 200! I was certainly not impressed with this rather unscientific explanation but lack of technical knowledge makes it difficult for me to debate on this matter. He also mentioned that I will need a minimum 8 batteries (?) to generate  a pure sine wave. 

I will appreciate if Andy or  anyone in the forum can explain the pros and cons of using a 24 volt instead of 48 volt.  Again is there any truth in saying that less than 8 cells will not create a pure sine wave?

Thanking in advance!

----------


## bones

any solution for hot water that doesnt 
involve the sun?

spoken to many friends some say it 
works some of the time others say it 
is sh_t and a waste of money others 
say gas is also a dead loss in winter 

what size generator do i need for hot
water? got a 7kwatt 25amp generator

----------


## IMHO

I am changing over to gas. Yes, winter is a bugger, but for 3 months only. I get 30 days on 48kg in winter, 90 days in summer. So you average 60 days on 48kg over a full year. 

That is for 2 bathrooms, used by 3 adults, plus scullery for the guest house kitchen only. No laundry or guest bathrooms. Highest price during the last year was R1100 and lowest R750 for 48kg. Shop around for gas, some outlets is very expensive. I also heard stories of unscrupulous people filling the cylinder with a percentage water to make up the weight, but I think it is the expensive guys telling the story trying to justify their prices. It is very easy to pick-up afterwards, as the cylinder is stamped with it's empty weight. 

So when the gas is empty, you weigh the cylinder and see if there is a difference, indicating water. I am yet to find a cylinder with water, but then again, I did not buy from the super cheap guys yet. It is normal to have a kg of gas left and the geyser stops operating. Above is from a Rinnai 21. I now started using Paloma, which so far is far superior in operation. It will be more difficult to judge the gas consumption however, as it is installed on two guest bathrooms and these rooms is not let out very often or consistently. I will have to find a way to monitor. 

If you go gas, be careful of the cheap units that does not have defrosters build in. (And all the safety gadgets) If your unit freeze in winter, you throw it away. If your municipal water pressure dips to the low side every so often, be aware that you will take cold showers. With the Rennai, I have to set the temp to a comfortable level to shower without mixing in cold water, because if you do, the change in pressure cause the geyser to shut down. My Paloma 21 however does much better in this regard and need much less water pressure.

Keep in mind that the units I am referring to use about 55w to operate and you need a UPS to make sure you can shower during a load shed.

----------


## AndyD

> Hello again, Today I found an Axpert 3KW MKS plus 24 volt system in a local shop with a price tag of  R7000 Inc Vat.


 That's a good price!!




> I checked with my contractor if it is okay to purchase that instead of the 48 volt system he chose for my system which was R2500 more expensive.  He was vehemently opposed to it and was concerned that it will put a 'lot of strain' in the system 24 volt inverter.


 The output of the inverter is rated in KVA so a 3KVA inverter will produce 3KVA output regardless of the input voltage.

The only downside in your case with using a 24v inverter rather than a 48v one is that the battery cables will need to be larger. This is one of the reasons that as the output power increases with the range of inverters so does the input voltage but with a 3kW unit it's still reasonable to use 24v input, hence the fact the manufacturers offer it as an option.  




> The best way he could explain the difference was by making a comparison between performance of  a C 180 merc vs C 200! I was certainly not impressed with this rather unscientific explanation but lack of technical knowledge makes it difficult for me to debate on this matter. He also mentioned that I will need a minimum 8 batteries (?) to generate  a pure sine wave.


 I don't know how to reply to that, it's the kinda statements I'd expect a wholesaler to come out with but not really an installer  :Wink: 

The number of batteries is immaterial as long as the inverter has sufficient to supply it with the correct input voltage. A 24v pure sine inverter will always produce a pure sine wave output regardless of the battery configuration as long as it's getting 24 volts from them. The inverter doesn't 'see' the individual batteries as such it just sees a pool of energy at a certain voltage so a 24volt inverter needs a minimum of 2x 12v batteries in series or 4x 6v batteries in series, it makes no difference which.

----------

blackknight72 (12-May-15)

----------


## Dave A

> The number of batteries is immaterial as long as the inverter has sufficient to supply it with the correct input voltage. A 24v pure sine inverter will always produce a pure sine wave output regardless of the battery configuration as long as it's getting 24 volts from them. The inverter doesn't 'see' the individual batteries as such it just sees a pool of energy at a certain voltage so a 24volt inverter needs a minimum of 2x 12v batteries in series or 4x 6v batteries in series, it makes no difference which.


Just a thought - One thing that might warrant consideration is voltage drop due to internal resistance in the battery, which would double (or more) at double the operating current. The simple solution to counter this would be to double up on the batteries in parallel.

----------


## AndyD

A lead acid battery is made up internally of multiple cells connected together. Each cell is basically 2 plates of dissimilar metals immersed in electrolyte (battery acid) and each cell produces about 2 volts nominally.


*2V Cell*

The size of the cell plates required to produce a high current is fairly large and wouldn't fit into a sensible sized battery casing so they cut the large plates into smaller ones and connect then together in groups like this. 

 
*2V Cells*

These are still a single 2 Volt cell same as the top drawing but it's just a more size-friendly format.

For a 6 volt battery they'd take 3 of these cells and plonk them into a case and wire them in series.


*6V Battery*

For a 12V battery they'd take 6 cells and wire in series.


*12V Battery*

----------


## AndyD

So whether you use 4 x 6Volt batteries cabled in series or 2x 12Volt batteries cabled in series to supply your 24Volt inverter makes little if any significant difference. Whichever combination you go for you've still effectively got 12 basic cells in series so they're topographically the same when it boils down to it.

----------

blackknight72 (13-May-15), Dave A (13-May-15)

----------


## Dave A

A great explanation of the relationship between current and reactor plate surface area, Andy  :Smile: 

I mentioned the issue more around the 48V vs 24V difference in the inverter systems. I was concerned someone might have thought halving the voltage of the battery system of the inverter would result in only half the number of batteries being required.

----------


## Justloadit

What is also important, when placing batteries in series and parallel, is that they must be of the same batch and same age. Rule of thumb is that when one battery of the series or parallel pack goes, the whole pack should be replaced.

The implications comes in the charging process, the faulty battery fools the charger and either under or over charges the full pack, because of incorrect feed back from the pack due to the faulty battery. Replacing the faulty battery with a brand new one, which will have discrepancies in the characteristics to the other batteries, will probably never work to its full potential, or may be over worked depending on how the battery pack is set up, series or parallel.

This situation is even more prevalent in Lithium battery packs.

----------


## AndyD

> ....I mentioned the issue more around the 48V vs 24V difference in the inverter systems......


Ahhh, I thought you were referring to the post you quoted where it says '_The inverter doesn't 'see' the individual batteries as such it just sees a pool of energy at a certain voltage so a 24volt inverter needs a minimum of 2x 12v batteries in series or 4x 6v batteries in series, it makes no difference which._'

----------


## AndyD

> What is also important, when placing batteries in series and parallel, is that they must be of the same batch and same age. Rule of thumb is that when one battery of the series or parallel pack goes, the whole pack should be replaced.
> 
> The implications comes in the charging process, the faulty battery fools the charger and either under or over charges the full pack, because of incorrect feed back from the pack due to the faulty battery. Replacing the faulty battery with a brand new one, which will have discrepancies in the characteristics to the other batteries, will probably never work to its full potential, or may be over worked depending on how the battery pack is set up, series or parallel.
> 
> This situation is even more prevalent in Lithium battery packs.


Faulty batteries can present issues. We keep on-site and off site records of battery banks which is useful and with most of our installations we have a 6 month service contract where we check the individual batteries for failed or short circuit cells, take hydrometer readings, top up electrolyte levels and check the output under load etc. 

The best strategy is to try to avoid single batteries going faulty in the first place. There's some key proceedures to be followed when installing battery banks and all too often they get overlooked which causes premature failures of a single cell or battery. A few key points are;
Arrange the batteres in such a way that they all have sufficient space between them for cooling.Terminations are critical especially when there's more than one string of batteries in parallel. A poor termination upsets the balance between the batteries, they won't be loaded evenly, they'll run at different temperatures and they won't charge evenly. Poor or corroded terminations are very common especially when contact paste isn't used on the lugs and terminals.Never let the electrolyte levels drop below the top of the plates.Set the minimum battery voltage correctly on the inverter. We come across inverters where the min batt voltage is still on it's manufacturer default setting and the batteries are being over-cycled.

----------


## IMHO

I heard or read somewhere that the higher your battery voltage, the better. More efficient conversion or something. The downside is the higher risk, and that you need thicker cabling. Any truth in that?

I was still waiting for your answer on my laundry room, Andy, but subsequently learned that it will have to be such a big installation, that it is not really worthwhile the effort to do the calculations. So do not waste your time on that. Thanks.

----------


## Dave A

> I heard or read somewhere that the higher your battery voltage, the better. More efficient conversion or something. The downside is the higher risk, and that you need thicker cabling. Any truth in that?


You certainly wouldn't need thicker cabling. 

The thickness of the conductive cable required is determined by the current, not the voltage. To produce the same power output off a higher battery voltage base would require less current, therefor thinner cables.

Spot on the efficiency issue though. When it comes to line resistance losses, the critical formula to bear in mind is E = I2Rt
Assuming the same line resistance, half the voltage would require double the current to produce the same power. But in doubling the current your line resistance loss in energy quadruples (22).

----------


## IMHO

Would this be true as well?

Assuming the same line resistance, double the voltage would require half the current to produce the same power. But in halving the current your line resistance gain in energy quadruples (22).

hehe, what do I know?

----------


## smitty

Disclaimer I'm a layman.

Longer cables of a given conductor material and thickness result in greater resistance.

Thicker conductors of a given conductor material and length result in lower resistance.

So keep your cables short and thick to reduce resistance. Oh and stick to copper for your conductor.

----------


## SilverNodashi

Simple rule of thumb with DC voltages: keep the cables as short as possible, and thick enough to pass through all the current you need. 
Generally, a 48V system would perform better than a 24V system, for a couple of reasons: V * A = Watt, so 24V * 100A = 2400W. 48V * 100A = 4800W, OR 48V * 50A = 2400W. Since you should only use 50% of your battery capacity, it would mean that in a 24V system you would need 200A battery bank, and 100A in a 48V system. The amount of batteries being used would be the same though, but your cables could be half the size. This shouldn't matter much in a short run, but could play a big role if your batteries can't be close to your inverter. 

The Axpert 24V inverter can also only use 600W (i.e. 2x 300W) solar panels, whereas the Axpert MKS 48V PLUS one could take 3000W (i.e. 10x 300w panels).

----------

blackknight72 (21-May-15)

----------


## blackknight72

SoftDux, that was very informative Indeed. My impression was that the impact of  having a low voltage system would be on cabling alone.I just bought an Axpert 24 volt 3 kw system. I am just wondering how many batteries I will need to sustain 2000 watt output for 2 hrs and at the recommended battery drainage of 50 percent. I have purchased four 225Ah 6 volt batteries assuming this will be okay. However my installer says the same inverter sustained power only for 50 minutes on 100Ah high cycle battery at 1000 watts output at a recent installation.  Any inputs in this regard by any members will be appreciated.

----------


## Justloadit

> SoftDux, that was very informative Indeed. My impression was that the impact of  having a low voltage system would be on cabling alone.I just bought an Axpert 24 volt 3 kw system. I am just wondering how many batteries I will need to sustain 2000 watt output for 2 hrs and at the recommended battery drainage of 50 percent. I have purchased four 225Ah 6 volt batteries assuming this will be okay. However my installer says the same inverter sustained power only for 50 minutes on 100Ah high cycle battery at 1000 watts output at a recent installation.  Any inputs in this regard by any members will be appreciated.


Energy of battery = V x A, 225A x 6 = 1350Watts
4 batteries in series = 24V, 4 x 1350 = 5400Watts total
Using up to 50% = 5400 / 2 = 2700Watts
If your load is 2000Watts, then 2700/2000 = 1.35Hours  or  1 hour and 21minutes

Your electrician says about a recent installation - 100Amps at 24V = 100 x 24 = 2400 watts
50% usage of energy = 2400/ 2 = 1200Watts
If load is 1000watts, then 1200/1000 = 1.2Hours or 1 hour and 12mins, if it only ran for 50 mins, then I assume that either the load was higher in power, or that there is losses within the inverter during the conversion process, at lower power loads on the inverter.

----------


## blackknight72

if I have to add additional batteries to prolong the back-up time should I stick with the same configuration of batteries as I have in the battery bank currently (4x6vx225 ah) or can I go for 12v cells (2x 12v x 200Ah)?

----------


## Justloadit

> if I have to add additional batteries to prolong the back-up time should I stick with the same configuration of batteries as I have in the battery bank currently (4x6vx225 ah) or can I go for 12v cells (2x 12v x 200Ah)?


When adding batteries in parallel, you must use the same make and model of battery and if at all possible from the same batch of manufacture. This is to ensure that all batteries get charged and discharged simultaneously.

ensure that the charger can handle the extra load, or else, the charge time doubles

----------

blackknight72 (21-May-15)

----------


## blackknight72

Although i originally planned to go with 6 volt cells for my 24 volt inverter, now I am considering to  go with 12 volt cells instead of 6 volt cells due to space issues. Both 225Ah. Are there any advantages or disadvantages in this regard?

----------


## ians

Draining a battery to 50 % on ever cycle would be going to extreme if the battery is a proper deep cycle battery and designed for that application. Not all batteries are capable of being drained to 50 %. 

It is in fact better to monitor the voltage of the battery. Once a battery drops below 10.4 volts you can start filling the cookie jar for funds to replace it.

It is not a good idea to work on rule of thumb for these applications. It could be an expensive learning curve. 

There are the few who know what they are doing and the masses who have learnt a few technical phrases and use it to baffle the public.

Dont believe read on the internet and make sure the person selling you stuff has a little more than the six months of shedding experience. 

People are burnt sore with generators and backup power supplies and incapable chargers for these huge battery packs.

----------


## smitty

> Draining a battery to 50 % on ever cycle would be going to extreme if the battery is a proper deep cycle battery and designed for that application. Not all batteries are capable of being drained to 50 %.


It is in fact better to monitor the voltage of the battery. Once a battery drops below 10.4 volts you can start filling the cooking for funds to replace it.

It is not a good idea to work on rule of thumb for these applications. It could be an expensive learning curve. 

There are the few who know what they are doing and the masses who have learnt a few technical phrases and use it to baffle the public.

Dont believe read on the internet and make sure the person selling you stuff has a little more than the six months of shedding experience. 

People are burnt sore with generators and backup power supplies and incapable chargers for these huge battery packs.[/QUOTE]


Ja I'd recommend reading the manufacturer's specification sheet for whatever batteries you are looking at.  E.g. a general purpose battery may only last 260 cycles at 100% discharge but more than 500 cycles at 50%. You could reach 1200 cycles if you only discharged by 30%. Note I've just read this from a spec sheet so I'd appreciate if there aren't any arguments on this point. ;-)

I bought some batteries (yes I read the spec sheet first) and stuck them in a UPS I already had. Discharging to 50% means I should get around 500 cycles from the batteries. It tends to get used every second day if there is stage two load shedding. Assuming stage two load shedding every day then I should get about two and half years from it. With a less pessimistic view on load shedding I should get more than that them. Outlay was less then R450.

If load shedding gets worse then I probably won't be using the UPS for a bit of light. Will have moved on to bigger and more expensive things by that point.

----------


## blackknight72

I am comparing Trojan 6 volt batteries and  12 volt batteries (both 225Ah) I read that 6 volt is superior due to thicker plates resulting in longevity. How true is this information? Comments appreciated

----------


## natal21

could you give me more details on how to contact you for prices on inverters

----------


## natal21

who supplied at that price please inform us all  :Smile:

----------


## Justloadit

Currently I have 500W modified sine running off a 12V Battery. If you are interested I can supply at R 945.00 excluding VAT.
I have used this model for about a year now and have not had any comebacks to date.

The electronics are fairly simple, and I have and can get spare components to be able to repair it at board level in case of a component failure.

----------


## IMHO

Somewhere I am understanding something drastically wrong.

I measured my equipment's amps using a clamp amp meter.

All together they pull 1,8 amp.

My understanding is that 1.8A x 230v = 414 watts

Yet, my 2000va UPS can not handle this. It starts moaning at 1.2A and more than that, it just switches off. Why is that? 2000va x 60% is 1200watt. So it should find 414 watt a breeze?

I checked my amm meter against the kettle now, kettle rated at 1850-2200 watt. It measures 8.5 A to 8.3 A. Which is just under 2000 watt. So meter seems fine.

----------


## Justloadit

aha - that is the difference between an expensive inverter and a low cost one. You probably need to verify the phase angle, or Power Factor. The more inductive load there is the more the low cost units struggle to maintain themselves in operation.

The overload trip is on the primary side, or low voltage side. When you have a high inductive load, you need a lot more amps to make the load work, because of the phase angle.

Most inverters are what we call 'unipolar' driven, in which only one side of the H bridge is switched at a variable high speed to create the sine wave, unfortunately when an inductive load is connected, this unbalanced switching causes the bridge to fire incorrectly due to the current being out of sync with the voltage, causing the bridge to over shoot when switching. This over shoot is what causes the primary side driver to use more current to work. Over shoot simply means that the two series power components are active simultaneously causing the link supply to be short circuited.

A bipolar switching process, has all 4 elements of the bridge switching a complex variable process to generate the sine wave. Since all the power components are active in the full quadrant, there is no overshooting, as the bridge elements now control the load with the supply.

The bipolar switching process is more complex and requires a higher quality switching devices and a few more inductive filters to ensure a pure sine wave. These extra characteristics makes the inverter more costly. 

That is why there is usually a huge difference between the China Mall inverters and the well known brands, which apply the bipolar switching process.

If you want to measure the phase angle, then you may need a power meter instrument I manufacture for R1650.00 excluding VAT.

Power Meter.pdf

Something else that I have come across, not all UPS's are sine wave, and the unit you have may be a modified sine wave, which is more sensitive to inductive loads.

----------

AndyD (27-May-15)

----------


## AndyD

> Somewhere I am understanding something drastically wrong.
> 
> I measured my equipment's amps using a clamp amp meter.
> 
> All together they pull 1,8 amp.
> 
> My understanding is that 1.8A x 230v = 414 watts
> 
> Yet, my 2000va UPS can not handle this. It starts moaning at 1.2A and more than that, it just switches off. Why is that? 2000va x 60% is 1200watt. So it should find 414 watt a breeze?
> ...


What Justloadit says is true but I'm puzzled about the size of the discrepency between the load and the UPS ability. 

Are you using an RMS clamp meter to measure the load current? If not your readings might not be accurate.Was your load being supplied by the UPS when you measured it? If so then a modified sine UPS could give a false current reading on some instruments.Is your load something like a fridge where there's going to be a start current that could be five times the normal run current just momentarily. If so your clamp meter might not have a high enough sample rate to see this current spike.

It does sound like there might be some other problem, I've not encountered a 2kva UPS that can't drive a load that's just over 400 watts even if the power factor is poor.

----------


## IMHO

Thanks guys. I will duplicate the exercise later, no time now, SARS is screaming for VAT.

I have some other 2000kva UPS's so will check them out as well. Just a bit pissed with myself, as I bought 3 x 12 volt batts, whereas the others only use 2.

----------


## tec0

Is R77K a good price for a 3KWA solar system "including batteries, inverter/components and solar panels" It feels a bit pricy to me...

----------


## AndyD

> Is R77K a good price for a 3KWA solar system "including batteries, inverter/components and solar panels" It feels a bit pricy to me...


 That's kind of a 'how long is a piece of string' type question without lots more details. Is that price for a completely off-grid installation? What inverter, what batteries and what panels are they quoting for (make and model numbers please) also how many of each? Did they include an MPPT charger or is this built into the inverter. Does the price include installation and any alterations to your existing DB and electrical installation (and CoC obviously)?

----------


## Justloadit

As Andy says, what is included in the kit?

----------


## tec0

Oasis II 324 3KVA 24V Pure Sine Inverter with intergrated 40A battery charger (1) 
Oasis Single Phase Bypass Box (1)
Trojan T105 - RE 225Ahr @ C20 6V Wet Cell Battery (4)
250W A-Grade Solar panels (6)
Outback 60A 12/24/48V MPPT Solar Regulator (1)

total price about R77k 

i phoned a few other companies see if i can get something a bit more cost effective.

----------


## natal21

> Oasis II 324 3KVA 24V Pure Sine Inverter with intergrated 40A battery charger (1) 3Kw pure sine wave bi-dirctional inverter with 60A charger R18 357.14
> Oasis Single Phase Bypass Box (1)maybe R2000
> Trojan T105 - RE 225Ahr @ C20 6V Wet Cell Battery (4) 2x12v 170 Ah lead crystal @r5400 each R10800
> 250W A-Grade Solar panels (6)6xR2350=R14100
> Outback 60A 12/24/48V MPPT Solar Regulator (1)approxR4000-R5000
> 
> total price about R77k Total R50257 approx not including connections and cables and labour or roof mountings etc.
> 
> i phoned a few other companies see if i can get something a bit more cost effective.


hope this helps

----------

tec0 (30-May-15)

----------


## SilverNodashi

> hope this helps


Those prices seems fair. Some places will charge more though.

----------


## tec0

It is crazy that "ALMOST" no websites have prices when it comes to solar stuff. I am looking for a reasonable system at a reasonable price. R70k R60k and R50K is not reasonable. Here is the thing our Proudly South African Products is all but missing. I have spend the last week trying to get hold of locals. Because we are told that we must support our local businesses/fabricators...  

The most i am willing to spend is about R20k to proof concept because there is no way in hell, i am going to spend R70K and have no other information other then "it is a big system" It is like buying a new car because the wheels are shiny...  :Slap: 

I want to know -> maintenance cost, parts cost, General problems with the system  because we need to know. But because that info is classified as beyond secret we just have to bite the bullet and test stuff out. Now i am not willing to to spend seven month's income on a whim...

----------


## IMHO

tec0, I feel you. Most of these also make obvious ridiculous claims, resulting in one not believing the little info they do give.

Look at the system advertised below. If run at 6KW , it will not last an hour, but they claim up to 8 hours. Total BS and misleading.

----------

tec0 (02-Jun-15)

----------


## vieome

http://www.donrowe.com/power-inverter-faq-a/258.htm

How long will battery last

----------

tec0 (02-Jun-15)

----------


## Justloadit

No one gives this information out, because of 2 reasons, one, is that they do not know what the are selling/supplying, they simply jumping on the band wagon to make a quick buck, and secondly, the ones that do know do not want to burst your bubble, when they advocate free energy!

There is a maintenance cost on batteries, it depends on usage, and how deep you regularly discharge your batteries. However, solar panels should last over 15 years. Inverters are like any electronic device, it depends on the manufacturer, and the quality of the components. The more serious the manufacturer, the higher quality goes into the product, and of course becomes more expensive. The China Mall stuff is cheap and nasty, and I caution customers to avoid it if they possibly can. 

Issuing verbal warranties, has about as much value in it as in nothing. Many suppliers use the so called factory warranty as part of their spiel, but ultimately, who carries the warranty? The supplier, as the manufacturer simply says to send the equipment back to China for repairs, the cost of transport over passes the cost of the equipment, so effectively you as the customer losses out.

The stuff I sell, I can repair in house, and therefor, has a limited warranty which I provide in case of premature failure.

When it comes to batteries, I give no warranty, simply because the battery manufacturers do not give any warranties either. The reason for this, is that a manufacturer can not deduce from simply looking at the battery what the customer has done. Over charged? over discharged? mishandled by customer? just far too many unaccountable variables.

I do get my batteries from a reputable supplier, and to date have gotten reasonable service out of them.

----------

tec0 (02-Jun-15)

----------


## AndyD

As with all items it's not a case of 'don't buy Chinese' it's a case of know what your buying and stick to the brands that are already proven reliable by their track record. Unfortunate price isn't always an indicator of quality especially in the unstable market climate we're in of everyone jumping on the UPS/inverter/solar bandwagon and a large proportion of the suppliers that have appeared on the scene will hit and run and not be around for the long haul. 

We've traditionally installed critical systems backup in the larger commercial and industrial market and the equipment is high-end but out of budget for the domestic and small business market that's recently exploded in demand. We've been looking for a cheaper product which is more basic but still reliable. 

Realistically most of the customers looking to reduce the effects of load shedding are not interested in many of the features the high-end products offer, they're not looking to connect PV panels, wind turbines and they don't need reports and monitoring etc, they're also not in need of the scaleability, they're just wanting selected appliances running for a few hours of power outage. 

We've installed a dozen or so of the Axpert inverters to date and so far they've performed well in the field so we'll continue to offer them as a budget option. The thing I like about them is that whilst they're somewhat dumbed down in features and flexibility they have a good range of units that offer different features and sizes etc and they're available from solid suppliers who can provide technical back-up and will honour their warranties. They won't cover every application we get requests for but that's also fine, if we can't apply them as a solution I'm happy to decline the customer. 

The biggest problems I've encountered is some of 'one size fits all' products around where it's sold as a complete system preassembled in a box. Some of these are being grossly mis-sold with their capabilities being obfuscated by stating their run time at a certain percentage of full load in the small print. I've had a couple of customers who've opted for one of these and on both occasions they paid less for the entire system than our quoted price for just the batteries on the system we designed for their needs. Needless to say it didn't end well, both are incapable of running for over an hour even though the salesliterature on both systems convincingly states they're capable of a 3 hour back-up time. One of them was especially impossible to determine the capabilities, they used a formula that assumed peak load for 5% of the time,75% load for 10%, 50% load for 30% of the time and 25% load for the remainder. No hard info on the capacity or the type of the batteries was stated anywhere so how anyone is supposed to design a system with this unit is completely beyond me.

I feel for you Tec0 but as a designer and installer I'm in as much pain as you are.

----------


## IMHO

How long, in years, can a battery last? The Deltec 1250 claim 2000 cycles at 10% DOD. If one is using it strictly for power outages say 3 times a week at less than 10% DOD, you will cycle it 156 times a year, which means you should be able to do it for 12.8 years. (2000/156).

Is this possible? Is the battery not going to pack up before that from age alone, never mind the cycles?

I suppose it could be possible if you do maintenance on the batts, but you cant, as it is sealed units.

----------


## IMHO

Can one check DOD by taking the volt measurements of a battery? My Deltec 1250 is fully charged at 13.1 volts. What should the volt readings be at 50%, 20% and 10% DOD?

----------


## AndyD

Yes, the depth you cycle you battery to will have a pronounced effect on the number of cycles in it's lifespan. Most batteries have predictive lifespan graphs available from the supplier where you can predict the number of cycles your batteries will survive and, from experience, they're fairly accurate if you're using a good charger and perform very basic maintenance.

13.1 volts sounds a little high, usually fully charged is just under 13 volts and the 50% discharge voltage is around 12.1-12.2v. Gel batteries are usually a little higher voltage that lead acid though. Using voltage to check battery charge is prone to innacuracies if the battery has been under recent charging or load conditions and temperature can also have small effects on the reading. You should never discharge a deep cycle leadacid battery below 12v as a rule of thumb which will by 75% discharged at that point. Also try not to leave the batteries in a low state of charge for any length of time, obviously if you're only using solar or wind to recharge them it might be unaviodable but in that case select batteries accordingly.

----------


## bergie

i see the axpert default cut off dc voltage is 21 volt on the 24 volt 3kva. the 48 volt 5 kva default setting is 42 volt. i wonder why they set it so low.

----------


## vieome

> It is crazy that "ALMOST" no websites have prices when it comes to solar stuff.


I have always wondered why  a lot of websites never put prices for their products. In a sense you end up wasting a potential customers time and company time, as they have to email or phone for a price. 

On another note
High demand has pushed up inverter and battery prices, but as more suppliers join the market(in hopes of making super profits)it will lead to a decrease in price. 

During power cuts my only need is lighting(gas stove). I bought a cheap chinese inverter 100W(R100) 50amp Battery (R800) Battery charger(R350) and runs three 11W lamps for about 7 Hours. Being using the setup for about 2 months now(Twice a week).

----------

tec0 (03-Jun-15)

----------


## Justloadit

> i see the axpert default cut off dc voltage is 21 volt on the 24 volt 3kva. the 48 volt 5 kva default setting is 42 volt. i wonder why they set it so low.


This is so you get the so called time of operation on the brochure. Following this route means that after approximately 30 cycles, your battery is dead.

I have had a problem with one of my customers, precisely because of this. He reckons the China Mall Solar inverter and charger is better than mine, because it runs for 2 hours longer than mine. What he does not understand is that my unit cuts out at 11.5V thereby prolonging the battery lifespan, as opposed to the competitive unit cutting out at 10.5V. I am now waiting and hoping for him to come back after his battery is dead and reverse his statement.

----------


## Justloadit

> How long, in years, can a battery last? The Deltec 1250 claim 2000 cycles at 10% DOD. If one is using it strictly for power outages say 3 times a week at less than 10% DOD, you will cycle it 156 times a year, which means you should be able to do it for 12.8 years. (2000/156).
> 
> Is this possible? Is the battery not going to pack up before that from age alone, never mind the cycles?
> 
> I suppose it could be possible if you do maintenance on the batts, but you cant, as it is sealed units.


The majority of batteries have a 5 year lifespan, unless you specifically look for and purchase a long life battery. You guessed it, cost is far much higher.

With respect to measuring the battery capacity, it is possible, but you require some very expense electronic equipment. I have been looking for one for a while, and found one at RS. ACT Battery Tester

----------


## tec0

I got hold of my old electronics books and sure enough i have something that might actually work and it will not cost me anything close to what we are being charged commercially. I just need to proof concept and if i don't set my workbench on fire or end up extra-crispy i will share the build. Oh this is going to be fun playing with 220 Volts and a Amp potential of almost 8 Amps and up... 

yea... some proper PPE will be a must...  :Rofl:

----------


## AndyD

> This is so you get the so called time of operation on the brochure. Following this route means that after approximately 30 cycles, your battery is dead.
> 
> I have had a problem with one of my customers, precisely because of this. He reckons the China Mall Solar inverter and charger is better than mine, because it runs for 2 hours longer than mine. What he does not understand is that my unit cuts out at 11.5V thereby prolonging the battery lifespan, as opposed to the competitive unit cutting out at 10.5V. I am now waiting and hoping for him to come back after his battery is dead and reverse his statement.



The Axpert inverters don't really give time of run figures in their brochure, the only time they give these kind of figures is in the owner/installation manual which contains a quick guide to suggested battery bank requirements but this isn't sales type info.




> i see the axpert default cut off dc voltage is 21 volt on the 24 volt 3kva. the 48 volt 5 kva default setting is 42 volt. i wonder why they set it so low.


The default setting is too low for my liking as well and I always set them higher. I did mention this issue somewhere else on the forum, maybe even on this thread (I haven't searched) but it's just one of the perameters you've got to set up when installing them. Also that cut-off voltage is being measured when the batteries are under load and I'm guessing it would be an uncompensated value so the figures in my last post won't necessarily apply.

----------


## HR Solutions

I have just purchased my very own inverter - works like a dream.   :Smile: 
tec if have the time to "build" your own inverter, good for you - I look at it entirely different.  Secondly if you build you own inverter and your house burns down or something happens, insurance will certainly not cover you !

----------


## Justloadit

> I got hold of my old electronics books and sure enough i have something that might actually work and it will not cost me anything close to what we are being charged commercially. I just need to proof concept and if i don't set my workbench on fire or end up extra-crispy i will share the build. Oh this is going to be fun playing with 220 Volts and a Amp potential of almost 8 Amps and up... 
> 
> yea... some proper PPE will be a must...


There are many circuits on the web, but all small stuff, and most of them are square wave, and probably involve a transformer which is driven at 12V and steps it up to 220V.
When you talk the large inverters, usually 2KW upwards, they tend to be pure sinewave, as there is no saving in the electronics by going modified sine wave. Whilst the H bridge to generate the sine wave from a DC link of 400V is relatively easy to get right, as opposed to converting/boosting the battery voltage from 12/24/48V to 400V link becomes another mission. Efficiency at these high power levels starts biting hard on your available battery energy. The biggest cost factor is the switching devices on the low end, along with the isolating transformers, along with respectable rectifying diodes which can handle the relatively high frequencies that one wants to use to reduce and improve the cost on transformers. This is where the heat of any inverter lies. 

Anyway good luck and have fun. When you finished, you will see that the prices may not be so outrages as thought on first glance.

As a matter of interest, I am currently looking at FETs which can switch 46A at 1200V at frequencies above 500KHz, with switching on times of 25nS and switch off times of 42nS and an on resistance of 85milli ohms. The only issue here is that they cost over R1K each. For the techies this is really a super new device. Lets just do simple calculation, lets say that we are using it in a 3Kw inverter, which translates to approximately 13Amps flowing through the device when it is on, so loss or power = Amps^2 * resistance.
13*13*.085 = 14.3Watts. Now in heating terms, this will be a very small heat sink, because heat is to the power of 2 when one needs to dissipate this heat. Lets take a current FET which would work in the same environment as the FET discussed, which has an internal on resistance of 427milli ohms. doing the same calculation as above,
13*13*.427 = 72Watts. The heatsink required to keep the device cool will be very large with a fan. This is almost as much energy a modern LCD TV uses.

----------

tec0 (03-Jun-15)

----------


## tec0

> As a matter of interest, I am currently looking at *FETs which can switch 46A at 1200V* at frequencies above 500KHz, with switching on times of 25nS and switch off times of 42nS and an on resistance of 85milli ohms. The only issue here is that they cost over R1K each. For the techies this is really a super new device. Lets just do simple calculation, lets say that we are using it in a 3Kw inverter, which translates to approximately 13Amps flowing through the device when it is on, so loss or power = Amps^2 * resistance.
> 13*13*.085 = 14.3Watts. Now in heating terms, this will be a very small heat sink, because heat is to the power of 2 when one needs to dissipate this heat. Lets take a current FET which would work in the same environment as the FET discussed, which has an internal on resistance of 427milli ohms. doing the same calculation as above,
> 13*13*.427 = 72Watts. The heatsink required to keep the device cool will be very large with a fan. This is almost as much energy a modern LCD TV uses.


yea my thinking was basically using a none conductive oil cool... Might work right... "same type of oil used to submerge PCs in. Think it is mineral oil not sure i have notes on it on my server will have a look get back to you on that. I know it is said that it doesn't do a good job at cooling stuff but that was the idea... 




> *FETs which can switch 46A at 1200V*


  do you have fact sheet on them if you don't mind please.  :Smile:

----------


## IMHO

Very interesting review on an ammeter/volt/watt meter. At R480 local pricing the Turnigy will have to do! Will it work on a lead acid battery, as it is really aimed at RC type batts, like Lipo etc.?

----------


## IMHO

> With respect to measuring the battery capacity, it is possible, but you require some very expense electronic equipment. I have been looking for one for a while, and found one at RS. ACT Battery Tester


At R5300 incl. you're right, it is damn expensive, wish I could buy one! It gives you only one thing and that is capacity left in the batt, but that is what I so desperately desire!

----------


## Justloadit

There is a number of new devices coming out. Have a look at this one C2M0025120D

Be aware of the on and off switching requirements, +20V and -5V for proper operation.

----------

tec0 (04-Jun-15)

----------


## tec0

The part that get me the most is that from tomorrow we may actually be without power for 8 hours a day...

----------


## IMHO

> The part that get me the most is that from tomorrow we may actually be without power for 8 hours a day...

----------

tec0 (04-Jun-15)

----------


## tec0

@ IMHO

On the 5th of June, some municipalities that couldn't pay Eskom on time will have be without power. The info i got from our local paper is 6:00 AM to 10:00 AM and then from 5:00 PM to 9:00 PM every day... Now tell me that doesn't suck. When you wake up no power.... When you go to bed no power... Our municipality is yet to make a statement we will see how that goes.

----------


## IMHO

Only if you live in one of these two places.

Free State residents living in Harrismith and Parys and surrounds are in for hours of blackouts daily, due to their municipalities' Eskom debt.

Ngwathe and Maluti-a-Phofung municipalities' electricity will be cut tomorrow at 10am, unless they reach an agreement with the power utility. 
Eskoms spokesperson, Khulu Phasiwe says the two municipalities collectively owe close to a billion rand.

Phasiwe explains that Maluti-a-Phofung owes over R600 million, and Ngwathe over R300 million.


Cheers!

----------


## tec0

Well according to official word it is they still need to pay in R94million by next week or will pay it i am not sure. Problem is without proper official statements it is impossible to figure out if the sword is hanging over our heads or what is really happening. It is sickening that Eskom to date made no statement towards our area and our municipalities said they are doing there best but that  R 97 million needs to be paid over. 

However, a decision by Eskom on when they will start to introduce the bulk interruptions remains a misery. We simply don't know and they simply cannot be bothered. So it is a "are the lights on today" scenario each time we wake up.  

If households and business fail to pay for whatever reason the situation may well go towards the fan... 

sorry couldn't get my animation to work  :Banghead:

----------


## smitty

Which municipality do you reside in?

Do you realise that Eskom has been in talks with all the municipalities that owe it money?

Why isn't your municipality keeping you informed with regard to the outcomes of those talks? 

Why do you think that Eskom should be communicating with you instead of the municipality who is their customer?

Have you asked your municipality if they're paid up with Eskom?

Have you asked your municipality if they're going to be cut off for non payment to Eskom and failure to agree to pay back what they owe?

Why do you think that Eskom (and by extension its paying customers) continue to supply your municipality electricity for free?

Bottom line is: 
It's your municipality and they are supposed to render services to you for which you pay them. If you're paying for electricity and you're not getting it because they're not paying their supplier (Eskom) for it then you need to give your municipality hell.

----------


## IMHO

Sjoe Smitty, maar jy is kwaai so vroeg in die oggend? haha

----------


## IMHO

tec0, I just know Eskom is playing a bluff game, trying to get the public to put pressure on their municipalities. Seems like they are succeeding in that. Escom will not cut any big areas. They and the ANC knows that that area will go up in flames. Will be interesting to see if they will chance it in the small Free State areas.

----------


## IMHO

Back to topic.

I got a digital LED ammeter yesterday. Learned a few things about shunts in the process. A picture says a thousand words, video probably much more. Will try and show you later.

----------

tec0 (05-Jun-15)

----------


## tec0

> Which municipality do you reside in?


Answer Mpumalanga  




> Do you realise that Eskom has been in talks with all the municipalities that owe it money?


Yes we are aware of talks and there was a lot of "ifs" mentioned.




> Why isn't your municipality keeping you informed with regard to the outcomes of those talks?


We are connected to there social pages but again we get a lot of "ifs" and the the same old...   




> Why do you think that Eskom should be communicating with you instead of the municipality who is their customer?


Because they are the only service provider in our country and they are on social media, surly we have the right to know the status of our debt? 




> Have you asked your municipality if they're paid up with Eskom?


There has been report that payments are being made in sums of millions but again no real feedback other then same old...    




> Have you asked your municipality if they're going to be cut off for non payment to Eskom and failure to agree to pay back what they owe?


On multiple occasions yes... It is said, it is up to Eskom, along with a maybe or maybe not and the same old... Or they just don't respond. 




> Why do you think that Eskom (and by extension its paying customers) continue to supply your municipality electricity for free?


Why must the paying public suffer the same consequence as the none paying public? Simple mentality remains... If you pay for a service then surly you have the right to access that service? Not just partial access but full access. Example you buy a car but the bank takes it on weekend for there own use? Will you accept that arrangement? Yes the bank paid for the car first but there where terms and conditions. If you violate them then the bank respond within months. Some of the debt is 5+ years old. Why not react earlier? It is a question of management on both sides not a question of payment and debt      




> Bottom line is: 
> It's your municipality and they are supposed to render services to you for which you pay them. If you're paying for electricity and you're not getting it because they're not paying their supplier (Eskom) for it then you need to give your municipality hell.


Have you tried this yourself? Where you successful?

----------


## tec0

> Back to topic.
> 
> I got a digital LED ammeter yesterday. Learned a few things about shunts in the process. A picture says a thousand words, video probably much more. Will try and show you later.


That will be cool thanks.  :Thumbup:

----------


## HR Solutions

Done and dusted ................ now I do not have to totally rely on Eskom  :Smile:

----------


## IMHO

> Done and dusted ................ now I do not have to totally rely on Eskom


Looks impressive, do tell the details!

Number of batteries.
Amp/Hour of batteries.
Brand and model of batteries.

Inverter size, brand, model.

Charger details.

What is the load you are planning to pull with the unit.

Price of the unit.

----------


## HR Solutions

Ellies FBIT2000
1200 W
2000VA
2 x Deep cycle batteries within black cabinet that is on wheels - 105amp each
So I have more than enough to power a quite few lights, 42inch flatscreen, DSTV etc 
I have had my name down for a while for this unit - just arrived and they are literally walking out of the shop  :Smile: 
Price R8500 including vat

----------


## AndyD

> Ellies FBIT2000
> 1200 W
> 2000VA
> 2 x Deep cycle batteries within black cabinet that is on wheels - 105amp each
> So I have more than enough to power a quite few lights, 42inch flatscreen, DSTV etc 
> I have had my name down for a while for this unit - just arrived and they are literally walking out of the shop 
> Price R8500 including vat


It certainly looks a lot more swish than my setup. Are you using it for powering other stuff such as router, PC's etc? I'm interested in how it performs, how long it takes to charge, how noisy is it and so on. Please let us know how it performs.

----------

tec0 (06-Jun-15)

----------


## HR Solutions

> It certainly looks a lot more swish than my setup. Are you using it for powering other stuff such as router, PC's etc? I'm interested in how it performs, how long it takes to charge, how noisy is it and so on. Please let us know how it performs.



Earlier this week I bought a smaller one because I was getting tired of waiting.  Then all of a sudden this came into stock today so I was very lucky to get it.  So I have taken the smaller one with one battery to work and have this one at home.  Does not make a sound at all except when I took its power source out and a fan came on.  Was just testing so don't know of any other noises but will let u know when we have a proper load shed. The fan noise sounded pretty quite and acceptable.  According to the spec sheet it will run for 4 hours with quite a lot of things attached.

----------


## tec0

I think by next month i will take a chance on cheaper import... i know... i know... I will check out the locals first and take it from there. I want a solar system. I payed for my home getting it off Eskom power seems like a good idea. 

Here is the math, 

My power bill is already really low because I use power saving products and gas for cooking. I also have a energy monitor that tells me to a T what my power bill will be. I am planning to install a gas water heater this month but i don't want it piped into my home due to the many stupid laws they have governing the install. So it is going to be a portable unit that will be mounted to a trolly system. Like the type you get for outdoor use. This will allow for added safety without compromising the house's piping in any way.  

This will allow me to switch the water feed from mains to my 5000L tank when needed. My tank is not inline as inline tanks need a 1000watt water pump to activate each time i turn a tap. That is just stupid so mine is totally isolated system that I can put inline at will at any time. The portable water heater will connect to this system and feed 16L per minute at a temp of 50 degree Celsius into my existing piping without any modification. I worked out the heat loss and will have 40 to 39 degree Celsius water flowing out of the tap. "Hot enough" 

Cool thing is i can still use my electric geyser... It has a timer installed on it so really I cannot complain. 

Installing the solar system, I will have 2000 watts per system there will be two systems "independent" The first system will be used to run my refrigeration only. Meaning I will only pull a maximum load of 400Watts of it. It will have a larger battery bank then the secondary system and the battery bank can also be charged from my generator "9000 watt 25 Amp generator" The second system will be sun dependent only with a smaller battery bank and will need to service a maximum load of only 300 Watts. It will drive the lights and my basics. The 300 watts is the max load i pull for my basics "tested" Last note the solar system will not be connected into the existing electrical. It will be a totally independent system.  

My house has a interesting build and I found the perfect placement for my solar panels. After doing some testing I know for a fact that I will get the morning and afternoon sun without much effort. 

This will be a 3 month project

==================================================  =====
edit
==================================================  =====

Only system that will still run on Eskom power will be my washing machine but it only runs for an hour every second to third day.

----------


## IMHO

I am playing with another idea currently. I saw I can not afford an off grid system. Too many batteries and the price kills it. So what if one goes grid tied without batteries? This will be purely to bring the Eskom account down and not for load shedding. (Which seems to be a thing of the past in any case) For that and other power outages, I will use my UPS system for mission critical equipment.

When my panels produce nothing or a bit, I will use Eskom. (At night and rainy days)

So, when the sun shines, I use my panels free electricity. When there is a shortfall, I draw from Eskom. When I produce too much, I dump it somehow useful as we can not feed back to the grid. I estimate about 36 panels @250 watt. Still a huge expense but I figure it will pay for itself in 5 years. 

First point of departure, I will have to get one of those smart meters to monitor my total consumption for a month, to see when I use how much power.

But is the idea possible? Say it is a cloudy day and my panels produce 2600 watt. Can one draw the balance (6000 watt) you need from the grid? Or is it a case of all or nothing?

What is all the equipment you need in such a setup called? What worries me the most, is how do you draw the shortfall from Eskom and marry it to your own. How do you dumb the excess by sending it somewhere else?

----------


## Justloadit

It is called a grid tied system, simply put is that the inverter is synchronised to the mains, and increases the voltage ever so slightly, so that the solar system provides as much power as the solar system can give and the balance is then provided by ESKOM. The only problem with this system is that the energy is only available when there is sun, and it may be when you really do not need this energy.

----------


## IMHO

Video as promised. 

For some reason the forum says it is an illegal file and will not show preview.

Here is the direct link.

https://www.youtube.com/watch?v=Sib9...ature=youtu.be

----------

tec0 (08-Jun-15)

----------


## IMHO

Here is the demo on the working and ammeter. I see that for a split second the amps is going into 30 amp. How long should it be over 30 amp to blow the fuse?

https://youtu.be/_uC_iKuyNpo

----------

tec0 (08-Jun-15)

----------


## AndyD

As Justloadit said, you'll produce most of your power around the middle of the day when you're probably not going to be able to use it. It works in Europe because the power company offers a 'feed in tariff' (FIT) so they pay you for power you put into the grid when you're not using it and this offsets the cost of the power you take out of the grid at another time when you do need it. 

There are inverters already available the can take multiple inputs and prioritise their use, look at the Victron Multiplus range for example,even the cheaper Axpert that I installed can do this in a limited fashion. You can connect PV panels, wind turbine, batteries and Eskom power and it will use you PV and wind power to supply the load and if there's insufficient power available from those it will make up the deficit using Eskom power. If there's surplus power coming from the PV and/or the wind turbine it can use this power to charge batteries if they're installed.

Without a feed in tariff I doubt it will be financially viable for a domestic premises to install PV and inverter without batteries, most of the power produced will not be used efficiently if it's used at all.

----------


## tec0

> Video as promised. 
> 
> For some reason the forum says it is an illegal file and will not show preview.
> 
> Here is the direct link.
> 
> https://www.youtube.com/watch?v=Sib9...ature=youtu.be


Love your UPS hack, excellent and your question is a damn good one. I spoke to a guy from Battery Centre and he told me my charger was killing my batteries now they are selling a charger that can charge deep cycle battery and it will cost me about R1250 for it. Now thing is with your normal UPS and i think you knew this already so sorry for repeating it. There is no real why to stop it from charging your battery because by design it just stupidly charge the battery to death "had a few UPS's" and if you check the voltages on them you will see that even when the battery hits 14 volts it just continue to charge. 

I have no clue how you will get around that yet.... That said YOU DID THE HACK! and not many can say that 

excellent post

----------


## daveob

> Here is the demo on the working and ammeter. I see that for a split second the amps is going into 30 amp. How long should it be over 30 amp to blow the fuse?


Hi IMHO

Hope you don't mind me chipping in here.

Video looks good. Well Done.

Had a look at the last few posts here and you seem to be rightly concerned about overcharging the batteries.

I see that you have 2 main possibilities here :

option 1 : 
control the charging by the UPS. 

You would need to identify the circuitry that charges the batteries. 

Then monitor the battery voltage and when it reaches the required level, say 14V or whatever the ideal voltage is, then disable the charging from the UPS.

Battery voltage can be easily monitored using a micro processor ( like an atmega328 IC chip ). The IC runs using 5V which can be supplied by the battery using a linear voltage regulator, and then connect the battery to an analog input pin using a voltage divider.

The voltage divider ( consists of 2 small R3 resistors and a capacitor ) basically scales the battery voltage down to a level that the IC can read. The IC can measure from 0V to 5VDC. So if your absolute max voltage on the battery under charge will be, lets say 20V to be on the safe side, then we need to scale the voltage down to 25% of the source ( battery ) and feed the scaled down voltage to the IC. The analog input pin of the IC has a 0 to 1023 scale, so is reasonably accurate.

So the IC would see 20V source as 1023 on it's analog scale ( 5V at the IC from the voltage divider ), 15V as 767 ( 3.75V ), 10V as 511 ( 2.5V )

Once you have that working, that same IC can control a transistor, which in turn controls a Solid State Relay, or opto-coupler, or any other device to turn the UPS charging system on or off.

The downside here is that you have no control over the charge rate.
Plus side of having the IC here is that you can also use it to monitor the voltage of the batteries when the UPS has no mains supply, and is discharging.

You may find your UPS will discharge the battery to, lets say ( just for an example ), 10V. But your battery supplier says you should not discharge below 11V to ensure the battery lasts 5 years longer.

So the voltage divider to the IC is used to monitor the battery voltage during discharge, and if it gets to a certain level, say 11.05V, then you disable the SSR or relay that connects the battery to the UPS. Yes, your appliances lose power, but your batteries live to fight another day.


Option 2 :
Disable the charging of the batteries by the UPS and charge them using a separate independent charger that is designed for different charge rates. 

There are a number of designs out there that will monitor battery voltage ( as described above ) and use PWM to control the charge and charge rate to the batteries, ranging from full power charge upto certain voltages, then reducing charge rate to a trickle or 'maintenance' charge.

Just my 2c worth.

----------


## daveob

Actually, having just thought about that, I think it also important to point out that in so many cases, people are spending small fortunes on systems to ensure that they have power when the outage hits - but little or no thought or concern about what happens when the power is restored.

There have been numerous mentions of routers that work erratically. The mains power is all over the place when it comes back on and everyone starts up at the same time. So if you're getting 180VAC into the router transformer that expects 200 - 240VAC, then the 12VDC output may not be 12V and the router starts doing weird things.

Or the TV set and sound system that you paid +R12k for that is subject to wild voltage swings on power up.

Or this pride & joy battery system. What happens when the power comes back on. Does the UPS immediately disconnect the battery and router the mains to the devices plugged into the UPS ? Most likely the case. What effect does voltage changes have on the charging circuit ?

The solution is to install a device that can :
1. prevent the mains power from being supplied down the line.
2. monitor the incoming mains voltage until it is above a set value ( eg. 200VAC ) and below 240VAC.
3. Start a timer ( eg 5 minutes, 15 min, etc )
4. delay the supply of mains power downline until the timer has expired ( unless the override button is pressed )

That way, you get to minimise the startup impact on your equipment.

----------

AndyD (10-Jun-15)

----------


## tec0

So basically micro controlling will become the norm here, I was thinking about a Arduino Uno, they can handle a lot of inputs and there are shields available for modification and the program IDE have a look at arduino. There is also a heavily supported library for it so copying and pasting code may well be an option "depending" 

I am planning home automation with it... I am sure a Google will give you results on how to make smart chargers and all the rest. There is a ton of stuff on YouTube. 

hope it helps a little

----------


## daveob

> So basically micro controlling will become the norm here, I was thinking about a Arduino Uno, they can handle a lot of inputs and there are shields available for modification and the program IDE have a look at arduino. There is also a heavily supported library for it so copying and pasting code may well be an option "depending" 
> 
> I am planning home automation with it... I am sure a Google will give you results on how to make smart chargers and all the rest. There is a ton of stuff on YouTube. 
> 
> hope it helps a little


Look at the Mega2560 instead. Has 54 I/O pins instead, and not that much more cost.

Personally I use a Mega2560 for home automation ( 3 x gate control, alarm system, sms to cell on trigger, web based control of gates, alarm, smart sensor control ( eg disable indoor passives in living room area when kids break beams in passageway in the morning, etc ).

Yes, you will find a lot of open source code based on Arduino for charge controllers, etc.

Just remember that boards like the Arduino have a 'per pin' and 'total board' current limit, so outputs are basically limited to an LED or an NPN transistor ( which in turn can drive much bigger loads ).

Once you have an Arduino, you can also use it to program a stand-alone atmega IC ( about R70 for atmega vs R350 for Uno ) so once your code is working, push it on to an atmega and reduce your hardware cost.

ps .. when you make a board for the atmega IC, use an IC saddle ( type of socket that the IC clips into ). If you have a system problem, very easy to remove the IC brains and replace it with the spare that you made.

----------


## tec0

> Look at the Mega2560 instead. Has 54 I/O pins instead, and not that much more cost.
> 
> Personally I use a Mega2560 for home automation ( 3 x gate control, alarm system, sms to cell on trigger, web based control of gates, alarm, smart sensor control ( eg disable indoor passives in living room area when kids break beams in passageway in the morning, etc ).
> 
> Yes, you will find a lot of open source code based on Arduino for charge controllers, etc.
> 
> Just remember that boards like the Arduino have a 'per pin' and 'total board' current limit, so outputs are basically limited to an LED or an NPN transistor ( which in turn can drive much bigger loads ).
> 
> Once you have an Arduino, you can also use it to program a stand-alone atmega IC ( about R70 for atmega vs R350 for Uno ) so once your code is working, push it on to an atmega and reduce your hardware cost.
> ...


Yes you are right on every aspect... I am just lazy  :Stick Out Tongue:  

yes it is expensive and yes Arduino is limited. What I like about it is the ecosystem it plugs into. The Arduino Mega R3 for example is a really nice board. Also i like to use the 4 Channel Relay Board For Arduino and it just works actually... Never had problem with it You can always adapt to a solid-state relay if you need to or even go to heavy-duty contactor using relay logic... It is a bit old school but it gets the job done.

----------


## IMHO

daveob, I would love to identify the charger circuit and hack it to float charge to 26 volt , or disable it all together. The problem is I am not an electronic boffin and do not know how to. I can Google and YouTube, but not knowing where the charging circuit is, stp me in my tracks. Can you help?

----------


## IMHO



----------


## daveob

> daveob, I would love to identify the charger circuit and hack it to float charge to 26 volt , or disable it all together. The problem is I am not an electronic boffin and do not know how to. I can Google and YouTube, but not knowing where the charging circuit is, stp me in my tracks. Can you help?


Hi IMHO

Sorry, but I have to be able to admit that what you are asking is not my area of expertise, so I would not want to give you incorrect info or advice, knowing full well that it could lead to disaster.

I can tell you a little about the pics you posted from what I can see. WARNING : this is all what I think I see. I have NO formal training or qualifications in this field :

pic 1 : a lot of these boards are designed as generic / multi purpose boards, so you will find a few holes on the pcb with diagrams printed on them for parts that are not populated. Those would be for a different model.

pic 2 : see the round black cylindrical thingy with the 63v printed on the side ? WARNING WARNING WARNING WARNING - those have big teeth. It is a capacitor that is designed to store energy. They are used to absorb fluctuations in the current flowing through them, making your ups run smoother and 'cleaner'. They are also designed to discharge that same energy - and can do so VERY fast. And even if your board is disconnected from the mains, they still retain their energy. If you touch the contacts on a capacitor, or short them together, there will be a shock, or a lot of sparks. One of the main reasons why warning signs are posted on things telling you not to open them. Ask me, I know. Was working on modifying a disposable camera flash bulb for a swim timing system a while back, and accidentally touched a 300V capacitor. After the feeling returned, my arm was still tingling for a few days.

pic 3 : that huge thing is, I suspect, a step up transformer. Most likely takes 24VDC input ( higher current = thicker wires ) and outputs 220VAC ( lower current = thinner wires ).

pic 4 : the 4 black cubes in the middle are relays. From what I can see, most likely magnetic coil switching relays.

Assuming the big transformer is a step up, the relays likely cause the 24VDC from the battery to be connected to the step up transformer when the mains fails.

The round black component with the red wire through it, at the bottom right of the relays, is a current sensor. That would detect when the mains has failed, and would cause the relays to kick in.

pic 9 : the board mounted to the back of the case contains the rs232 comms plug, and the phone in / out plugs for surge protecting of the phone line. The 5 cable plug connects the comms board in the pic to the charge pcb. That comms board would have no effect on the charging of the batteries.

Pic 9 also looks like the mains in to the UPS are connected directly to the output sockets on the UPS. That means the mains, when present, will flow directly from the input to the output. Only when the mains fails, will the pcb connect the battery to the transformer and output 220V to the output sockets.

pic 10 : the notably thicker wires are probably the wires from the battery to the board, and / or from the board to the transformer. They are thicker so that they can carry more current. ( ignoring AC and DC for now, 1A @ 220V would be 220Watts, but 220W @ 24V = 9 amps. Amps = current, so higher current needs thicker wires.
Same logic is used for solar PV panels. Connect in series to increase voltage = lower current = thinner wiring needed from panels to charge controller.

pic 11 : shows an IC ( chip ). This is most likely something like an atmega or pic chip that is programmed with the 'logic' for the board and controls what it does.
The item at the top left that is bolted to the silver heat sink would be either a FET or a voltage regulator. There are some small capacitors close by ( the light brown 'blob' components ) and these are typically used to smooth the output of the voltage regulator. It should have numbers printed in the voltage reg. something like 7805 ( the '05' indicates that it supplies 5VDC output ) and would be used to regulate the voltage that the IC chip needs to run.
The round black component at the bottom left with the hole in the top is a piezo buzzer. Very low current but very noisy and irritating beeper when the UPS is running. I dropped a spot of pratleys quickset on the top of mine and it is a lot quieter.

Sorry, but I know this does not really help you one bit, but hope it does give you some idea of what those components are.

If you really want to do mods to this board, you may want to look at some of the electronics forums, of put a job up on fiverr ( $5 ) for someone to source you a wiring diagram / schematic and to tell you what to modify.

----------


## AndyD

> Actually, having just thought about that, I think it also important to point out that in so many cases, people are spending small fortunes on systems to ensure that they have power when the outage hits - but little or no thought or concern about what happens when the power is restored.
> 
> There have been numerous mentions of routers that work erratically. The mains power is all over the place when it comes back on and everyone starts up at the same time. So if you're getting 180VAC into the router transformer that expects 200 - 240VAC, then the 12VDC output may not be 12V and the router starts doing weird things.
> 
> Or the TV set and sound system that you paid +R12k for that is subject to wild voltage swings on power up.
> 
> Or this pride & joy battery system. What happens when the power comes back on. Does the UPS immediately disconnect the battery and router the mains to the devices plugged into the UPS ? Most likely the case. What effect does voltage changes have on the charging circuit ?
> 
> The solution is to install a device that can :
> ...


I did make a thread about this a while ago because it's something that's often not taken into consideration at the design stage of a back-up system and it affects the entire spec including the battery requirements and the selaction of appropriate inverters etc.

Another solution to add to the 4 you mentioned is to replace the power supplies on any devices such as routers, alarms, PABX's etc if the original has a tight band of voltage requirement. I did this with my Netgear router, the original power supply plug was the heavy transformer type and was rated for operation between 220-240 volts, I purchased an equivalent switch mode type supply with a wider voltage band of 100-250 volts and it solved a lot of random conectivity and networking problems I was having.

----------


## tec0

Ok what inverter to use, i am told that some inverters can actually damage the refrigerator? I am asking this because I am getting into contact with a supplier that sells a 9000 Watt system for R36k That is not bad because it is a complete working system. Thing is I don't know the makes and parts so in the end I am stepping on a real risk of getting shot in the foot...  

Questions I will be asking.
How strong are the Solar panels?
Can the inverter be used on electronics like TV, DVD player, PC Refrigerator and Freezer? 
How long will everything last under load?
Can the batteries be charged from a second source "like generator"?

Please add your question here...

----------


## daveob

> I did make a thread about this a while ago because it's something that's often not taken into consideration at the design stage of a back-up system and it affects the entire spec including the battery requirements and the selaction of appropriate inverters etc.
> 
> Another solution to add to the 4 you mentioned is to replace the power supplies on any devices such as routers, alarms, PABX's etc if the original has a tight band of voltage requirement. I did this with my Netgear router, the original power supply plug was the heavy transformer type and was rated for operation between 220-240 volts, I purchased an equivalent switch mode type supply with a wider voltage band of 100-250 volts and it solved a lot of random conectivity and networking problems I was having.


Hi AndyD

I recall that thread. Although I agree with your solution and how the problem was solved, my first concern would be the fact that this 'proves' that the mains supply after an outage is most certainly not clean or stable. I have a basic home entertainment system - nothing fancy - TV, DVD, sound, PVR, VHS ( yes, VHS ), TV games, etc, but combined it probably easily costs in excess of R20K. 

So while the R600 router is now working ( working = operational, not protected from accelerated electronics wear and tear ), the R20K entertainment system is still subject to 'severe electrical abuse'.

This is partly why I started working on my solution. The prototype is done and working, and I am now waiting for PC Boards to be produced.

Essentially the "Mains Delay" unit will block mains power to the EC ( entertainment center ) until the mains voltage is consistently in the 210 - 240V range, and then the "Mains Delay" unit has an internal timer to wait a preset number of minutes ( eg 5, 10, 15 minutes ).
Only after the timer has run, will the mains be switched on to the EC.

The minimum voltage spec, as well as the number of minutes to wait, is set by the user with the buttons on the side of the "Mains Delay" unit.

Another very good use for this is on power tools and industrial equipment.

Saw another post ( might have been part of your original post ) about a power tool having been left on at the start of outage, and serious hazard when power comes back on. Am thinking grinders, drills, soldering irons, etc.

Simply install this unit at the plug point, set the 'time delay' to '0', and once the power is restored it will block the mains power to the equipment until the user presses the button on the unit.

That was originally added to the design because I was tired or the missus complaining ( twice !! ) that all the PVR auto-tune and recording settings were lost when the PVR rebooted, unless you 'cancel' the Scan during the PVR bootup.

Another perfect place for this is on the supply to my UPS.

UPS is great when the mains fails, but on restore, the batteries are 'switched off' and mains supply, no matter how dirty and nasty, is sent directly to my PC. Had 2 PCs in the last 18 months that popped when power came back on.

Bottom line is, as you say, put some serious thought into protecting your equipment. Not just when the power dies, but more importantly what it is subject to when the mains returns.

----------


## daveob

> Ok what inverter to use, i am told that some inverters can actually damage the refrigerator? I am asking this because I am getting into contact with a supplier that sells a 9000 Watt system for R36k That is not bad because it is a complete working system. Thing is I don't know the makes and parts so in the end I am stepping on a real risk of getting shot in the foot...  
> 
> Questions I will be asking.
> How strong are the Solar panels?
> Can the inverter be used on electronics like TV, DVD player, PC Refrigerator and Freezer? 
> How long will everything last under load?
> Can the batteries be charged from a second source "like generator"?
> 
> Please add your question here...


Hi tec0

I would be looking at info like :
1. what voltage are the panels ?
2. configuration : Series or Parallel.
3. what size wire is needed from panels to charge controller.
4. what are the battery specs.
5. what is the efficiency rating of the inverter ?
6. what is the normal and max output of the inverter ?
7. how many batteries, and series or parallel ?
8. Cooling
9. Ventilation
10. can the controller also accept input from a wind turbine ?
11. where does it dump power when batteries are charged ? Can this be connected to a water heater / pool heater element ?
12. what is the battery charging schema ? what is the max voltage / amp sent to the battery. when does it step down as the battery approaches fully charged and at what values, how does it maintain charge ?

As a general run of thumb, you can work on the following :

assuming 2 x 12V 105aH deep cell batteries, connected in series.
So you get a 24V x 105aH power source.
24V x 105aH = 2520 watts of power. But that is from fully charged to absolutely completely dead - dead as in destroyed )
So you get the battery specs, and find the absolute maximum discharge limit.
Remember that hitting that max limit will mean the life span of the batteries is seriously reduced.
So maybe you decide to work with a 50% discharge limit.
So 2520 watts x 50% = 1260 watts ( usable battery power ).
Next it has to pass through the inverter.
Cheaper inverter = less efficient.
Lets say it is average quality, and eff. is 75% ( so you lose 25% of the energy in the inverter conversion )
1260 watts x 75% = 945 watts. btw, that other 25% does go somewhere - heat from the inverter = ventilation requirements.

So you can look at the specs on your appliances and work out just how long you can run things for with that amount of power.

Personally, I would not run anything with a motor from an inverter ( unless it is a true pure sine wave inverter, but thats $$$$$s ) . It is not good for the motor. AndyD would likely be able to better explain why.
Also I would not connect anything that is power hungry, has an element of any kind, etc.

A lot of the suitability of this system is going to depend very heavily on the batteries. Their replacement cost is a huge chunk of the cost of the system. Make sure you know everything about those batteries, discharge rates, limits, etc before you part with your cash.

Get an independant price for the replacement of the batteries, and factor this into your 'total cost or ownership' as they will need replacing. How often ? depends on usage and abuse. I would probably estimate around 5 years. Sounds long, but if you have 4 batteries x R1500 each = R6000 = average R 1200 per year additional cost. Battery specs will say a life span of something like 10 years. Yes, 10 years - in IDEAL situations, perfect charging schema, minimum discharge rates, etc. This is the real world - half their number.

In case you didn't know, batteries have different life expectancy based on rate of discharge.
Pull that 1260 watts from the battery in 10 minutes every day, and the battery might last 1 year.
Pull same 1260 watts from the battery over 2 hours every day, and it may last 10 years.

Look carefully at the specs.

2c


ps .. you mentioned 9000w

Is that 9000w total battery X 50% discharge limit X 75% inverter efficiency = USABLE 3375 watts ?  Big difference.

9000 w would be around 8 batteries  ( 8 batteries x 12v = 96V x 100aH = 9600W x 50% x 75% = 3600 usable )

If it is 9000w usable, it would need :
9000 usable = 9000 / 75% / 50% = 24000W / 100aH / 12V = 20 batteries.

Replacement cost = 
8 x R 1500 = R 12000
or
20 x R 1500 = R 30000

Based on just the replacement cost of the batteries, it is highly unlikely that the system you are looking at for R36K, including panels, charger, etc, contains 20 deep celll batteries.

Chances are it has 6 or 8 batteries, making the usable watts around 3600W - a lot less than the 9000 watts.

Ask lots of questions without letting on that you know what you know. If the answers you get are not adding up to what you know, then chances are everything you're being told is 'subject to exageration'.

----------


## IMHO

> Another perfect place for this is on the supply to my UPS.
> 
> UPS is great when the mains fails, but on restore, the batteries are 'switched off' and mains supply, no matter how dirty and nasty, is sent directly to my PC. Had 2 PCs in the last 18 months that popped when power came back on.
> .


Excellent . I lost 4 power supplies to my PABX and eventually the R40K PABX as well.

Edit: From behind a UPS.

PPS: Maybe the fact that the UPS's batteries was shot and switched on and off the whole time when the AC fail had something to do with it... 
;-)

----------


## IMHO

daveob, i did n fiverr request, thanks for the tip. Did not know about the fiverr concept.

----------


## IMHO

techo, I understand mppt is also very important. Maybe someone can explain.

----------


## Justloadit

> techo, I understand mppt is also very important. Maybe someone can explain.


MPPT Maximum Power Point Tracking

----------


## daveob

> techo, I understand mppt is also very important. Maybe someone can explain.


also a good laymans explanation here :

http://www.solar-electric.com/mppt-s...ntrollers.html

----------


## daveob

In case anyone following this post is interested in the idea I mentioned, I have just created a new post.

MainsDelay is now a GO project.

http://www.theforumsa.co.za/forums/showthread.php/18563-Mains-Delay-Life-After-Loadshedding

----------


## Voicesource

> those prices are very expensive . i sell the 5kva axpert for cheaper than the 3kva you have being quoted on. i install as well. i use the bosch 105AH 12 volt batteries. 4 in series.
> the 5kva model can be paralleled up to 6 inverters and has a built in powerful mppt solar charger. 
> i am however looking for enclosed battery cases for 4 batteries. i have been making my own.


Hi Bergie,

I was interested in your Xpert inverters from Voltronic power. Do you have stock and if s at what prices?

----------


## bergie

hi voicesource . at the moment i am also paying a fortune for the last few inverters. supply and demand. stock comes in at the end of the month. i dont really sell them loose,only with installation.

----------


## smitty

> UPS is great when the mains fails, but on restore, the batteries are 'switched off' and mains supply, no matter how dirty and nasty, is sent directly to my PC. Had 2 PCs in the last 18 months that popped when power came back on.


That depends entirely on your UPS. A UPS need not only intervene to supply electricity from battery when the supply fails but it can also intervene when the power is too dirty (spikes, drops, etc).

The cheap and cheerful UPSes are probably only going to provide power in the event of power failure.

----------


## smitty

> Hi tec0
> 
> As a general run of thumb, you can work on the following :
> 
> assuming 2 x 12V 105aH deep cell batteries, connected in series.
> So you get a 24V x 105aH power source.
> 24V x 105aH = 2520 watts of power. But that is from fully charged to absolutely completely dead - dead as in destroyed )
> <snip>
> So 2520 watts x 50% = 1260 watts ( usable battery power ).


Do you mean watts or whatt hours?




> Hi tec0
> In case you didn't know, batteries have different life expectancy based on rate of discharge.
> Pull that 1260 watts from the battery in 10 minutes every day, and the battery might last 1 year.
> Pull same 1260 watts from the battery over 2 hours every day, and it may last 10 years.


Battery capacities are often specified at their 20 hour rate.  E.g. 105 amp hours at 20 hours means it will supply 5.25 amps for 20 hours.

In such a case you're going to struggle to draw half the battery's capacity in 10 minutes. It's not a capacitor. ;-)

----------


## daveob

> Battery capacities are often specified at their 20 hour rate.  E.g. 105 amp hours at 20 hours means it will supply 5.25 amps for 20 hours.
> In such a case you're going to struggle to draw half the battery's capacity in 10 minutes. It's not a capacitor. ;-)


Hi smitty

Sorry, I assumed it would be understood that I was not quoting real / exact / calculated numbers. I was making a comparison to show, by example, that the battery that is discharged faster will have a shorter lifespan.

----------


## daveob

> That depends entirely on your UPS. A UPS need not only intervene to supply electricity from battery when the supply fails but it can also intervene when the power is too dirty (spikes, drops, etc).
> 
> The cheap and cheerful UPSs are probably only going to provide power in the event of power failure.


Yes. The majority of typical household / small office UPSs that I have seen work in the 'cheapie' fashion. The mains input is connected DIRECTLY to the UPS output. The pics posted a few days ago of the UPS circuits also confirm this.

Unfortunate that the average user does not know this and thinks the UPS is 'protecting' their PC. It is not.

----------


## ACEsterhuizen

:Confused:  Congratulations guys now I am am back to properly fragmented with serious RAM issues.  :Wink:  Most of the tech guys I buy ups's from cannot even answer these questions.  (eg Types Of UPS's)

What is the most common type of ups's we use locally? And which one would be the most effective (cost and other) to use?

----------


## smitty

> Congratulations guys now I am am back to properly fragmented with serious RAM issues.  Most of the tech guys I buy ups's from cannot even answer these questions.  (eg Types Of UPS's)
> 
> What is the most common type of ups's we use locally? And which one would be the most effective (cost and other) to use?


Most popular is Line Interactive because it's cheap and works pretty well.

Don't bother with Standby. That is very old technology and any small saving isn't worth it. Basically it switches to battery when the power drops of spikes sufficiently.

Online (double conversion) is expensive to buy and uses more power to run. It produces beautiful, clean output power though. It can also clean up dirty power without going to battery. Good for running expensive servers and medical equipment off dirty power (e.g. from small generators).

Line interactive is pretty much in between then two. Both cost wise to buy and run and also ability. It does require the use of battery power when the power is dirty.

Note that even within the categories you'll get different price and performance points. A good quality Line Interactive UPS will beat the pants of a cheapie. Things like how quickly it kicks in, battery size, how long it can run for before overheating, etc.

----------

ACEsterhuizen (16-Jun-15)

----------


## ACEsterhuizen

why is this technology so "primitive" ?   (joke)

----------


## blackknight72

Hi, I had a major setback with the installation of my inverter.  When the setup was finished, the inverter flashes an error message showing battery overcharging. Any idea what could be the cause. The batteries are Trojan T125s with Axpert inverter. Thanks in advance!

----------


## AndyD

Did you set the battery type to flooded in the program menu? I think it's perameter 05 should be set to 'FLD' for lead acid baytteries but check in your manual. If it already is then try setting to 'user defined' and set the low alarm and other voltages manually later in the program.

----------


## tec0

**************************
edit 


 Built-in intelligent battery charger prolongs battery life
 Battery saving function prevents the batteries from going flat when not in use
 Low battery disconnect function automatically disables inverter when batteries reach minimum charge
 Fossil fuel and pollution free
 Input power : 24 Volt DC

FBIT2000.pdf
FBI2000W.pdf
pricecheck

**************************

This is the FBI2000W inverter/uninterruptible Power Supply AKA UPS unit build by ELLIES and available at a cost of about R8550 (give or take) for the unit. You get two 12 Volt 100 Amp batteries "depending on model and distributor and specifications. It is  cool looking system and is like a normal UPS we all love and know form the PC world. 

This unit is able to handle a second set of batteries or so i am told. So it works just fine BUT there are a few things you need to know about this system. 

First and foremost is the running cost. It will consume about 129 Watts of power while charging (again based on this model others may be more or even less) Batteries will set you back about R1600 to about R2500+ depending on make or model. 

Secondly it has two settings. The one is called "Narrow" and the other is called "Wide" Now the trick here is you need to identify what you want it to do. If you want to run. The "Narrow" setting is used for "tube lights, energy saving lamps Television set" NOTE NOT SUITABLE TO MEET HIGH POWER MOTORS and they even warn you about a PC... The mode runs within 170-280Vac 

Now the second setting "Wide" is recommended for things like "lamps and or a fan" The mode runs within 90-280Vac and is not as sensitive or so the manual claims.       

Now on a high load you will get a couple of hours but according to the box and manual on lower loads it will last longer. Now my power load will be in the 240 watt range so i am not to worried. 

But base on the info i got i will be installing a second system just for my Freezer and refrigerator and this one will be used for my basics.  

Last thing when you turn it on it will make a fizzing noise and if it switches to the inverter the fans kicks in and does make a noise. 

Cool thing is the power consumption my generator can charge this system with ease and that to me is a big plus. 

hope this helps

----------


## Justloadit

At 129Watts consumption for battery charging, it is going to take approximately 12 hours to reach 80% of battery capacity if your 2 batteries are discharged by 50%, and the another 12 hours will be trickle charge mode to get 100% capacity.
Running your genny for that long, you might as well connect the loads directly to the genny.

----------


## tec0

> At 129Watts consumption for battery charging, it is going to take approximately 12 hours to reach 80% of battery capacity if your 2 batteries are discharged by 50%, and the another 12 hours will be trickle charge mode to get 100% capacity.
> Running your genny for that long, you might as well connect the loads directly to the genny.


I noticed something but want to make sure before i post it here, I think it is regulating itself but i am not sure yet so i want to test it with tomorrow's load-shedding and see how much it will pull for charging thereafter. But this is not fact yet so let me first get firsthand data for us. I have a suspicion that it might actually consume more power if the batteries are drained. I added the above in the edit section "Built-in intelligent battery charger"  the word intelligent may well suggest that this may be the case but because i don't know yet i cannot say it is 100% true. 

I rather test it and give you my actual readings that way we know fact from fiction.

----------


## tec0

Ok it is self-regulating and pulls about 200 Watt "give or take" i cannot get a clean reading from my power monitor but it appears to be 200 Watts. It does go down as the batteries gets charged. That said i had lights i watched the news, did computing had my creature comforts. In total i consumed 271 Watts of power from the system. It wasn't that loud, it didn't get hot. I am happy with the product. But i will be adding a second bank of two 12 volt 100 Amp batteries very soon. Because today we where without power for basically from 10 AM to about 9 PM not due to load-shedding... something went wrong according to local news. 

By using my generator for my refrigeration and my inverter "at night" i cannot complain.

----------


## Justloadit

Yep sounds like the charger pushes 200W so effectively it will charge you bank in 24 hours. Just remember that by adding more batteries, the charger may not be able to charge the full bank in 24 hours

----------


## tec0

> Yep sounds like the charger pushes 200W so effectively it will charge you bank in 24 hours. Just remember that by adding more batteries, the charger may not be able to charge the full bank in 24 hours


I am thinking about adding a second bank because it will help me a lot. At times our power is out for about 12 hours continuously normally the excuse is feeder cables and or theft. Regardless we cannot function anymore, our home became nothing more then a cold dark cave. So we are forced. I will be thinking about buying a second system rather. Same inverter but will be buying other type of batteries. The Batteries are still deep cycle batteries but over all cheaper and supplied by battery centre. They are also 12 Volt 100 AMP batteries 

I finally got a quotation for complete solar system. It runs towards the R59K mark. It is not a bad system pushing about 3000-Watts. It can also charge from both solar and mains and that is always a plus. 

Anyhow the system as it is now, I am happy with it... What i would like to add is a second system and perhaps keep the loads low on both.

----------


## blackknight72

> Did you set the battery type to flooded in the program menu? I think it's perameter 05 should be set to 'FLD' for lead acid baytteries but check in your manual. If it already is then try setting to 'user defined' and set the low alarm and other voltages manually later in the program.


Hi Andy, 

Thank you for your earlier feedback.

Today the electric contractor came to check the settings in the inverter again. According to him the setting was right. The batteries were checked twice and we're found not faulty. The inverter works normally in DC mode. However when power is back it shows the message that batteries are over charging. The contractor says the batteries are supposed to be 100 AH where as mine is 240ah. From what I can remember you were using 225Ah. Do you think this could be a problem? I was offered T125s in the place of T105s as they were not available and because of more or less same spec. I downloaded the user manual for Axpert inverter and it mentions the recommended battery amperage as 200Ah. I am so worried since I am not sure if the battery seller will replace it. Awaiting your input.

Jay

----------


## blackknight72

I picked up two issues while chatting to the contractor today evening. He  was using 4AWG instead  of 8 AMG for cabling. After installation apparently the inverter tripped while the kettle was switched on. Obviously he forgot to exclude that line. Can any of these lead to faults leading to battery over charging?  having sleepless nights  :Frown:

----------


## AndyD

> Hi Andy, 
> 
> Thank you for your earlier feedback.
> 
> Today the electric contractor came to check the settings in the inverter again. According to him the setting was right. The batteries were checked twice and we're found not faulty. The inverter works normally in DC mode. However when power is back it shows the message that batteries are over charging. The contractor says the batteries are supposed to be 100 AH where as mine is 240ah. From what I can remember you were using 225Ah. Do you think this could be a problem? I was offered T125s in the place of T105s as they were not available and because of more or less same spec. I downloaded the user manual for Axpert inverter and it mentions the recommended battery amperage as 200Ah. I am so worried since I am not sure if the battery seller will replace it. Awaiting your input.
> 
> Jay


I think the reason they recommend 200Ah batteries is because of the capabilities of the charger but I've installed 3Kw Axpert inverters with paralleled double battery banks of T105's so I can't see how a single bank of 240Ah could be a problem.  




> I picked up two issues while chatting to the contractor today evening. He  was using 4AWG instead  of 8 AMG for cabling. After installation apparently the inverter tripped while the kettle was switched on. Obviously he forgot to exclude that line. Can any of these lead to faults leading to battery over charging?  having sleepless nights


 I'd suggest your battery wiring should be minmum of 35mm sq which, if you want to work in American Wire Gauge is very close to 2AWG. Peak DC current could be easily 100Amps with a 3kW 24v inverter for example.

Start at the beginning, outline exactly what system you have, please give inverter model number and the number of batteries and their exact configuration. Please also double check your stated 4AWG DC wiring is definitely what was installed. I'm not trying to run you around in circles I just want to rule out any possible basic causes before we go looking deeper.

----------


## blackknight72

> I think the reason they recommend 200Ah batteries is because of the capabilities of the charger but I've installed 3Kw Axpert inverters with paralleled double battery banks of T105's so I can't see how a single bank of 240Ah could be a problem.  
> 
>  I'd suggest your battery wiring should be minmum of 35mm sq which, if you want to work in American Wire Gauge is very close to 2AWG. Peak DC current could be easily 100Amps with a 3kW 24v inverter for example.
> 
> Start at the beginning, outline exactly what system you have, please give inverter model number and the number of batteries and their exact configuration. Please also double check your stated 4AWG DC wiring is definitely what was installed. I'm not trying to run you around in circles I just want to rule out any possible basic causes before we go looking deeper.



Hello Andy,

Many thanks for your response.

I am using Axpert 3KW MKS plus 24 volt inverter with four  240Ah (Trojan T125) 6volt batteries connected in series with a fuse to protect the batteries based on your input. I asked the electrician to put up a mini DB to for the essential circuit. However while the inverter was connected and undergoing testing a kettle was switched on which was not bypassed and hence the machine tripped. Apparently it worked for an hour without issues.

The electrician acknowledges that he has used only ' flexible DC cable' instead of any of the recommended AWG wires. Could this be a factor leading to faulty charging?

The model number of the inverter is SOL-I-AX--3MPLUS24.

Hope this information is adequate.

----------


## AndyD

A kettle could quite easily cause overload, kettles are a high load especially if they're these new fast boil types. Overload is not likely to damage the inverter, I've run my Axpert into every type of overload possible including a range of short circuit faults and it's not shown any signs of damage so I doubt very much the kettle caused the issues. 

I can't see anything wrong off-hand with the setup you mention, I'd suggest being absolutely methodical, recheck and remake every battery and fuse termination to start with.

----------


## blackknight72

> I think the reason they recommend 200Ah batteries is because of the capabilities of the charger but I've installed 3Kw Axpert inverters with paralleled double battery banks of T105's so I can't see how a single bank of 240Ah could be a problem.  
> 
>  I'd suggest your battery wiring should be minmum of 35mm sq which, if you want to work in American Wire Gauge is very close to 2AWG. Peak DC current could be easily 100Amps with a 3kW 24v inverter for example.
> 
> Start at the beginning, outline exactly what system you have, please give inverter model number and the number of batteries and their exact configuration. Please also double check your stated 4AWG DC wiring is definitely what was installed. I'm not trying to run you around in circles I just want to rule out any possible basic causes before we go looking deeper.


Andy, Thank you so much for the response.

The system is as follows. 

Axpert 3KW MKS plus 24 volt
Model number SOL-I--AX--3MPLUS24
Batteries four 240Ah batteries (T125) connected serially with a fuse
Cabling: 'flexible DC wiring' (not any of the AWG rated) he says it is a thick cable.
A mini DB was put to isolate essential circuits to the inverter.

Batteries checked twice by the contractor and the battery supplier and found to have no faults.
settings checked for battery by installer and he couldn't see any issues.

Works normal on DC. Shows fault code 3 when AC is back after a brief delay.This is where we stand now.

----------


## blackknight72

Just now noted your earlier response. The seller has agreed to change the inverter for a new one. I am trying it tomorrow. Hoping for the best.

----------


## AndyD

I really think it's a very very slim chance that the problem is being caused by the batteries being 240Ah. If the installer really can't find the problem then either he needs to install another similar inverter to see if the fault persists or not or try 4 different batteries on the existing system in order to localise the fault to either the inverter or the batteries and cabling.

----------


## tec0

update, we had a long power-out yesterday, no problems really system lasted for 5 hours and had power left in the end. was pulling 240 watts "got LED lights" installed that took the demand down a bit. My TV consumes 115 Watts of power but i will be downing it soon. Looking for a better TV. my hope is to get it to an even 200 watts. 

Generator took care of my refrigeration... I will not be adding batteries to this system i am planning on building a second system rather that will have 2 banks of batteries... Batteries I am looking to use are 6Volts but pushes 150 AMPS. Just want to confirm that the charger would be able to handle it first.

----------


## AndyD

Good to hear your system is working for you, whatever you install that's what's important at the end of the day. 

I'd question whether it's necessary to accomodate your refrigeration on your back-up system but I gather from the general chatter that some areas are getting longer shedding periods than others. In CT we're generally getting 2.25 hour outages and my chest freezer goes from -19C to -15C in that period when it's half full. My fridge ends up around 10C in the same period so I didn't consider it necessary to have them running on my inverter. Obviously if you're having 5 hour outages it may be a different ballgame entirely.

Chargers are incredibly important, don't skimp on them. Cheap and nasty battery chargers are the fastest way to destroy perfectly good batteres. Make sure any charger you buy is at least 3-stage with a float charge as well. I can recommend the Optimate chargers for smaller battery systems.

----------


## Tonye

> A kettle could quite easily cause overload, kettles are a high load especially if they're these new fast boil types.


Hi Andy. Tevo used to do a Kettle, Brand Name Bennett Read Smart Flask. These were available in 6,8 litres & 4,8 Litres.
Power consumption 750w. Thet were also well insulated and kept water just under boiling point.
Unfortunately they do not sell them anymore.



I found a 1,5 litre Kettle with double stainless steel wall, which also keeps water hot for up to 4 hours.
Make is Sunbeam. Power consumption 1350w. Available at Makro @ R299.00



Have you heard of a Devel inverter.
Had a client who purchased one. It is a 24v 1500w Pure sinewave.
It looked quite impressive with different settings for different types of batteries & also an auto neutral to earth connection on inverter mode.
The client intitially had an electrician in to do the wiring. They connected the 220v input to the battery terminals of the inverter.
Fortunately they never powered the system on.
Then the client figured out where the 220v input was supposed to be connected. They then connected two 12v batteries in parallel instead of
series. Again fortunately they did not power up the system.

I went to assist them with a complete changeover system with dedicated UPS Plug socket.
I also added an ammeter with a chart that informs the client the amps been used & calculates battery life using a 80% efficiency & a 50% depth
of discharge.

----------


## HR Solutions

> They then connected two 12v batteries in parallel instead of
> series


A lot of the systems I have seen have been in parallel ..... why are you saying it should be in series ? (I am a layman, therefore do not know, but I do know what parallel and series is)

----------


## bergie

if its a 24 volt inverter. you would connect the 2 x 12 volt batteries in series to get 24 volt. if parallel it then you still have 12 volt in total but double your amp/hour.

----------


## HR Solutions

aaah ok thanks  :Smile:

----------


## Dave A

> & also an auto neutral to earth connection on inverter mode.


Now that's a nice touch! Does the Axpert do that too?

----------


## tec0

Got a scary scary one for you Andy... Friend of mine is a qualified electrician with all the right papers. He was asked to do some tests. This is what the owner did. The owner connected the neutral wire on the copper pipes and then just took a life-wire from the DB box and basically wired his home like a car.... There was no earth wire in sight obviously not because it would have tripped the mains. 

My friend just give them a quotation on rewiring everything and left hoping they don't phone him again. He said he was never so afraid to work on a roof in his life! Needless to say they did phone him again and after a while "two weeks" the home is now wired like a home and past inspection.  

How is that for scary....

----------


## AndyD

> Now that's a nice touch! Does the Axpert do that too?


 No, unfortunately the Axpert doesn't do this, it comes with L and Neutral floating WRT Earth.




> Got a scary scary one for you Andy... Friend of mine is a qualified electrician with all the right papers. He was asked to do some tests. This is what the owner did. The owner connected the neutral wire on the copper pipes and then just took a life-wire from the DB box and basically wired his home like a car.... There was no earth wire in sight obviously not because it would have tripped the mains. 
> 
> My friend just give them a quotation on rewiring everything and left hoping they don't phone him again. He said he was never so afraid to work on a roof in his life! Needless to say they did phone him again and after a while "two weeks" the home is now wired like a home and past inspection.  
> 
> How is that for scary....


 Sounds a bit like the old TN-C systems they used to install, they're not allowed nowadays. What you describe is a very dangerous installation which should be disconnected.

----------


## tec0

a while back friend of mine installed a solar system but it got vandalized as the thief tried to remove the panel. About R20K worth of panels was vandalized. Eventually they took the system off and sold it as they couldn't be at home 24/7 protecting it. My thinking now is, is it worth it? It is expensive and not something one could hide. Now before the demigods spew out there filth it is worth nothing that these types of thefts happen all the time on most farming communities along with generator theft. 

Knowing this i started to Google for smaller solutions as one can put them under lock and key if the need is there. This is what i found.

----------


## bones

that looks cool but will it set the house
on fire?

----------


## blackknight72

Is there a way of calculating approximate back up time when battery banks are connected in parallel?  (Total of eight 6volt batteries 240Ah)

----------


## blackknight72

> Is there a way of calculating approximate back up time when battery banks are connected in parallel?  (Total of eight 6volt batteries 240Ah)


That is at 2000 Watt consumption. I would also like to know if it is okay to add a second bank at a later stage. Will it damage the first group of batteries?

----------


## ACEsterhuizen

Nice simple calculator

----------

blackknight72 (08-Jul-15)

----------


## blackknight72

That is  :Cool:

----------


## blackknight72

My inverter installation is almost complete. However when I switch the kettle on with the mains on , the inverter beaps with a message indicating overload. Why does this happen when the mains are supplying. I connected the kettle on another plug point still with mains on and there was no problem at all. Any clue what could lead to this?

----------


## tec0

I know in older homes if you turn something on like a kettle the lights would "dim" for a second and go normal again. Could it be that turning on the kettle creates a dip in the power flow for a second that causes the beep?

----------


## Justloadit

You may have a UPS inverter, in other words the load is always supplied by the inverter, and the battery is always on charge/stand by, so effectively the load can then not exceed the UPS rating at any time.

----------


## blackknight72

> You may have a UPS inverter, in other words the load is always supplied by the inverter, and the battery is always on charge/stand by, so effectively the load can then not exceed the UPS rating at any time.


It is an Axpert 3KW MKS plus.

Interesting enough the Inverter doesn't bleep when i use the same kettle in other power points.

----------


## blackknight72

Interesting enough the Inverter doesn't bleep when i use the same kettle in other power points.

----------


## AndyD

I'm not sure why that would be.

Did you sort out the problem with the inverter error code indicating overvoltage on the batteries? What was the cause out of interest?

----------


## blackknight72

> I'm not sure why that would be.
> 
> Did you sort out the problem with the inverter error code indicating overvoltage on the batteries? What was the cause out of interest?


Yes, it was sorted out after a lot of confusion and unnecessary tension. The inverter was found to be faulty and was replaced with a new one. Afterwards a faulty kettle triggered alarm for overloading. Just finished with the installation this week but we haven't had any load shedding after that. I shall post some pics soon. Many thanks for sharing your experience  in tge forum which led me to experiment with the current setup, much against the opinion of local gurus!

----------


## malcolmpearson

Hi guys

I have been following this thread with great interest, thanks mostly to AndyD...

I am installing one of this RCT 5000, so far the install is:

RCT 5000W Axpert Hybrid Inverter
8 Royal 100Ah Deep Cycle batteries - could not get the 200Ah
Cables to connect the batteries to each other and Inverter - rather more expensive than I thought (R700 with fuse)
100Amp DC fuse for the battery bank

Nothing installed yet, but here is my idea:

The batteries connected with 2 parallel connected sets of 4 in series (basically 12Vx4=48V and then in parallel to the other 4x12V=48V giving me 48V at 200Ah)

Now my question is now the solar panels:
I am looking at the ArtSolar Pinetown Durban produced 250W panels at around R2100 excluding VAT vs the SolarWorlds 260W at R2800 ex VAT. It would be great to hear if somebody is using this locally produced solar panel and how it performs.

The RCT spec on the Solar Panels is as follows:
SOLAR CHARGER
Maximum PV Array Power 3000W
MPPT Range @ Operating
Voltage 60VDC ~ 115VDC
Maximum PV Array Open
Circuit Voltage 145 VDC
Maximum Charging Current 60A
98%
Standby Power Consumption 2 W

My understanding is that I can connect 8 x 250W solar panels to this hybrid = 2040W to be within the 3000W range?

The specs for the solar panels are:
ELECTRICAL DATA @ STC 250Wp
Peak Power Watts - PMAX (Wp) 250Wp
Power Output Tolerance - PMAX (%) 0/+3
Maximum Power Voltage - Vmmp (V) 30.3V
Maximum Power Current - Impp (A) 8.27A
Open Circuit Voltage - VOC (V) 37.6V
Short Circuit Current - ISC (A) 8.85A
Reverse Current - IR (A) 18A

Do I need to concern myself with the open circuit limit or the maximum power current? Are the 8 panels going to exceed the limitations of the hybrid inverter/charger?

----------


## AndyD

Yes the string voltage will be critical to the performance of the system, it's something you should be concerned about. I don't have the specs of your inverter to hand, does it have a built-in MPPT tracker? If you're not sure I'll see if I've got time tomorrow to find a spec sheet.

----------


## malcolmpearson

Thanks Andy

Here are the specs as per link - we have the 5KVA - I could not get this PDF to paste properly....here is the link sorry!

http://shop63.co.za/image/data/Docum...t%20MKS-A4.pdf

----------


## malcolmpearson

My calculations up to now think I could do 3 parallel connected strings of 3 of the 250W PV panels (9 in total) - that would keep me below the open voltage and below the max amperage and max voltage?

----------


## malcolmpearson

A question:
I have used a 100amp fuse on each bank of 4 x 100Ah batteries - is this an overkill?

And I see the manual mentions that you should have a manual switch for the batteries from the inverter - is this necessary?

----------


## blackknight72

Hello Andy,

Last year during the peak of power outage, upon inspired by your thread I installed an Inverter. The input from that thread and the forum members were of great help in this matter. Now I am back with another scenario. I am probably one of those many unfortunate people who installed the inverter and discovered that there is no long shedding. Here in East London we haven't had any outages for the last 8 months or so and I assume that is the same in most towns. My inverter didn't have to kick in even for an hour since installation! Now I am worried that the batteries might get damaged if I do not take them through a discharging process. Hence I switch of the mains once a week to facilitate discharge. Considering that potentially there will be no challenges in the power sector for a while at least I would like to look at a more practical solution to the current situation.

I have two options. I can sell them off. The total investment was around 25 grands. If I am lucky to find a buyer I may retain 50 percent. The other option would be to attach PV panels. My unit is Axpert 3KV MKS plus. The  question is will it be a worthy exercise to invest more around this. I have no idea how much expensive it is to install panels. While I am not sure how many of you are caught in the same situation like me,If you or anyone else has insight into this please share with me.

----------


## AndyD

I think a lot of people are in the same boat where they spent a fair amount of money on back-up solutions only to find they got limited use out of them and I do feel sorry for those who waited a long time before jumping on the bandwagon only to find the load-shedding stopped shortly afterwards. Your particular case is the worst possible scenario and you never even benefited from the outlay and installation. Nearly all of the inverters we've installed have been for commercial clients and mostly with the disruptions to trading they were suffering they'd paid for themselves after the first few episodes of load shedding. I guess you've got to look at it like car or house insurance where it's peace of mind whilst you have it and if you don't claim during the 12 month policy term you wouldn't start regretting the outlay and wishing you'd never bothered. 

I have a homemade mains fail counter on mine that records the number of power fails and the total duration of running on battery back-up and since it was installed there have been 88 instances of power fail and the total back-up time is 149.7 hours. A few of these power fails were when we had an earth leakage tripping issue and once every 2 or 3 months I manually trip the power and load test the system so at a guess about 60-70 of them maybe would have been due to Eskom. I used a lot of second hand materials and installed it myself, its capital outlay to me was around R14K so every power outage that I've had back-up power for has cost around R215.00 or R93.00 per hour. Also not cheap but having a home office, if I had to make the same decision today with 20/20 hindsight I'd still have gone ahead with the install. 

I use a 5Amp Optimate charger to condition the batteries. Every 6 months I've been removing the batteries, topping them up where necessary, checking the specific gravity of the electrolyte and putting them through a 'conditioning cycle' whereby the Optimate discharges them and recharges them and supposedly 'desulphates' them. Has it worked?..... I don't know TBH. 

We recently had a planned power outage for 12 hours whilst local Eskom/Council supply transformers were replaced/upgraded and the inverter ran for about 8.5 hours before shutting down on low battery voltage. During this time all my 2x computers, 2x routers, 2x servers, TV, laptop, printers, phones and various small chargers etc were all running, the espresso machine was used 3 or 4 times being unplugged in between each use and there were 12v LED lights which are direct off the same batteries running throughout the house. This was by far the longest power fail we've encountered and the system performed beyond my expectations and far beyond its design duration so maybe the conditioning charge is working.

I'm going to keep my back-up system, it's resale value isn't sufficient to warrant ripping it out and being without it. That said I'm not going to invest any further money in PV panels etc because there won't be sufficient operational benefit or return on the capital outlay. I can't really advise on what you should do, I'm not even sure how much inverters and batteries are selling for second hand. Part of the 25K you paid was for the installation so really you need to remove that amount from the equation before working out what percentage you'll recover you you sell. I don't see any reason you shouldn't get at least 50% of the new price for your inverter but second hand batteries are a lot more risky and I'm not sure many people will be happy to take that higher risk unless the price was low enough to warrant it.

----------


## SilverNodashi

I would also keep the system, if you can afford it. Loadshedding isn't over. No until we get new power plants with proper maintenance contracts and electricity prices become more affordable for the masses again. Partial reason for load shedding in many smaller towns are often the fault of overloading a transformer / sub station due to stolen electricity. Just yesterday, the power was off in Witbank, from 9am to 4PM for maintenance. This is probably fine on a Sunday, but imagine it was in the week. Many businesses would have lost R25k right there. 

Depending on what batteries you have, you could get away with cycling them every couple months only. Get the datasheet off the internet and see how many months it can be stored without a charge. Then discharge and recharge it, say 2 weeks before that period. The fewer times you discharge the batteries, the longer they will last.

----------


## bergie

i would keep the system and go the solar panel route. your 3 kva axpert has a built in solar charger. i am doing the same with my 5 kva axpert. i plan to run my pool pump,lights and other light duty appliances in the daytime. i will use the batteries for a short while at night,with a high cut off voltage. with eskom prices going up and up ,it will pay itself off quickly.

----------


## Justloadit

Well in my area in Johannesburg, I have had a good number of power fails, and on 3 occasions, the cables were stolen. When cables are stolen, the period to power returned varied from 8 hours to 30 hours. Fortunately I have a 10KVA genny as part of my arsenal.

The biggest problem with most inverters with built in chargers, is that they continually supply a float charge to the battery. This is what kills the battery if you do not cycle your batteries at regular intervals. Connecting solar panels, does maintain the batteries at full energy, and goes through the switching off period of approximately 15 hours. This allows the chemistry to 
recover.

I suggest that you should look at acquiring an grid tied inverter. What this does, is that it supplies power to your load by the amount that your panels can provide, there by saving you on the Eskom electricity meter. At least then you will get some money back for your investment.

Just remember, the reason for no load shedding is because industry has reduced in size, the high number of unemployment is testament to this, both in manufacturing and mining, and some of the large smelters have shut their doors. When the economy picks up (I am being optimistic here), and industry starts growing, and power required, we will have load shedding again. Right now, every couple of evenings, we get messages on the TV to switch off loads which are not required, because the grid is strained - so what about the story that the power problem is something from the past?

----------


## AndyD

Lol, I like it. You've got 4 different approaches suggested to the problem which is great.




> .....Get the datasheet off the internet and see how many months it can be stored without a charge. Then discharge and recharge it, say 2 weeks before that period....


 I advise against keeping lead acid batteries discharged for any period of time. If you wanted to 'store' the batteries so they don't deteriorate until a time comes when load-shedding may start again then I'd suggest draining the electrolyte entirely.




> i would keep the system and go the solar panel route. your 3 kva axpert has a built in solar charger. i am doing the same with my 5 kva axpert. i plan to run my pool pump,lights and other light duty appliances in the daytime. i will use the batteries for a short while at night,with a high cut off voltage. with eskom prices going up and up ,it will pay itself off quickly.


 Did you do the numbers on this? I just assumed it would be financially viable but I'm interested to hear your take on it.




> ....Right now, every couple of evenings, we get messages on the TV to switch off loads which are not required, because the grid is strained - so what about the story that the power problem is something from the past?


 Are they still asking people to reduce load during peak times? I had no idea, I very rarely watch TV and I haven't seen anything in the newspapers. I'm assuming there's zero actual load-shedding nationwide....I only know what's happening in CT. I'm also wondering if they're still load-shedding selective industrial customers and effectively robbing Peter to pay Paul so the general population (read _voting population_) wouldn't need to have ,load-shedding any more ??

----------


## AndyD

Thought I'd update this and see how everyone else's system has performed and hopefully are still performing.

My system is still running and the only maintenance it's required in just over 3 years is topping up the water in the batteries several times. About 3 months ago I removed the batteries and connected them to my Optimate charger and ran a diagnostic cycle on them, thankfully they're all tested good so I think the Trojans were a good buy and they should still have a good few years use left in them. The Axpert inverter also proved itself to be a solid unit, I ran it hard... right up to it's specification limits for 15-20 minute durations on numerous occasions and it never gave any problems so that was also a good buy. 

My system was a Godsend back in the days we were having scheduled load shedding but it's not been used much since. At that time it allowed me to have my work computers, servers, router, phones, coffee machine and lights running. Since then it only kicks in maybe once every 4 months when there's an electrical outage or I forget to top up the pre-paid meter and another couple of times a year when I test it. Looking back on it now I wonder if it was worth all the effort and expense. From purely a domestic convenience point of view such as being able to cook dinner, have lights and internet and watch TV during load shedding it probably wasn't but considering how many days it also kept my home office running it certainly made it all worthwhile.

----------


## Justloadit

Looking back, I am glad I spent my money, I reckon I got my moneys worth. I had already purchased my inverter in 2008. I have had to replace the batteries on 5 occasions, and learnt a hard lesson with respect to the older type inverters with built in charger, and so called 'trickle charger' to keep you battery topped up. This trickle charger is a killer because it eventually damages the battery. The newer charges are supposed to shut down and only come in once the battery voltage falls to a predetermined value.

Every time I have replaced the 8 batteries, I went to a smaller capacity. Started off at 100A per battery wet cell, now down to 20A gel, and still get about 4 hours usage, since I have reduced power by getting more efficient equipment. Some few years back I also purchased a 11KW diesel generator, and have run some 200 hours since I have had it. The number of times we have had power failures, due to cable theft, and other outages, if it is less than 30 minutes the UPS runs my essentials, anything more than half an hour,  I switch the genny on and run my house on it.

----------


## SilverNodashi

> Looking back, I am glad I spent my money, I reckon I got my moneys worth. I had already purchased my inverter in 2008. I have had to replace the batteries on 5 occasions, and learnt a hard lesson with respect to the older type inverters with built in charger, and so called 'trickle charger' to keep you battery topped up. This trickle charger is a killer because it eventually damages the battery. The newer charges are supposed to shut down and only come in once the battery voltage falls to a predetermined value.
> 
> Every time I have replaced the 8 batteries, I went to a smaller capacity. Started off at 100A per battery wet cell, now down to 20A gel, and still get about 4 hours usage, since I have reduced power by getting more efficient equipment. Some few years back I also purchased a 11KW diesel generator, and have run some 200 hours since I have had it. The number of times we have had power failures, due to cable theft, and other outages, if it is less than 30 minutes the UPS runs my essentials, anything more than half an hour,  I switch the genny on and run my house on it.


That's my experience as well. They're cheap, but they work fairly decent for the price.

----------


## AndyD

> Looking back, I am glad I spent my money, I reckon I got my moneys worth. I had already purchased my inverter in 2008. I have had to replace the batteries on 5 occasions, and learnt a hard lesson with respect to the older type inverters with built in charger, and so called 'trickle charger' to keep you battery topped up. This trickle charger is a killer because it eventually damages the battery. The newer charges are supposed to shut down and only come in once the battery voltage falls to a predetermined value.
> 
> Every time I have replaced the 8 batteries, I went to a smaller capacity. Started off at 100A per battery wet cell, now down to 20A gel, and still get about 4 hours usage, since I have reduced power by getting more efficient equipment. Some few years back I also purchased a 11KW diesel generator, and have run some 200 hours since I have had it. The number of times we have had power failures, due to cable theft, and other outages, if it is less than 30 minutes the UPS runs my essentials, anything more than half an hour,  I switch the genny on and run my house on it.


Wow, sorry to hear about your battery problems. What inverter are you using that destroys the batteries so quick? Battery life was something of a worry I had when I bought the Axpert, because it was a fairly new model at the time there were no reviews or reports about it's charging abilities and battery lifespans. Luckily so far so good, I'll be happy if I get 5 or 6 years battery life but I guess only time will tell.

----------


## Justloadit

Will check up and let you know.
A majority of the built in chargers, have this trickle charger in it. When it is a solar driven charger, this is not a problem, because there is a rest time overnight, however when it is a mains driven charger, then there is this continuous power being pushed into the battery. If the battery is cycled onto battery power a minimum of once a week for an hour or two, then the trickle charge is not an issue. However if there are months and months in which the inverter does not work, this is where there slow degradation of the battery occurs due to the continuous trickle charge. I look at it as a slow (un-) plating process of the battery chemistry as a picture to the reason of the degradation of the battery.

----------


## pedromartins

I have found the the Ellies invertors, both the 12v 600w and the 24v 1200w systems, do not charge the batteries sufficiently. If I take the 12v system which I have 2 batteries of 105a/h and 65a/h, = 170a/h. My load is 260w. I get around 2hrs of backup time with the Ellies. If I charge the batteries seperately on a intelligent charger, I will get 7 hrs of backup time. I found the same problem on the 24v system using deep cycle batteries as well.
Has anybody else experienced this?

----------


## AndyD

Hi Pedromartins. What's the model number of your inverter and what make and model number are your batteries?

----------


## SilverNodashi

> I have found the the Ellies invertors, both the 12v 600w and the 24v 1200w systems, do not charge the batteries sufficiently. If I take the 12v system which I have 2 batteries of 105a/h and 65a/h, = 170a/h. My load is 260w. I get around 2hrs of backup time with the Ellies. If I charge the batteries seperately on a intelligent charger, I will get 7 hrs of backup time. I found the same problem on the 24v system using deep cycle batteries as well.
> Has anybody else experienced this?


sadly those inverters were cheaply built (though you paid a lot for it due to 3-5 middle men) and generally don't have a decent charging circuit.

----------


## ians

> sadly those inverters were cheaply built (though you paid a lot for it due to 3-5 middle men) and generally don't have a decent charging circuit.


I have to agree with you on this...i have had a lot of problems with these units "frying" the batteries...people are "dumping" them. The little scare we had recently with load shedding has surfaced a lots of these old units, which are now dead. 

I plan to strip one and see if i cant salvage parts from them and make a DIY power bank, using lithium batteries and a better charge unit. I do realize it is going to cost a little more however in the long run it might be a way better option. Add in a solar panel and we will be onto something. 

I have been following a DIY fella who converts cars into battery powered ones. My son is building and modify old V8's. I am gona chat to him about doing a DIY conversion to an old cheap body. Your computer will share more info than you need, if you ask the right questions. Sometime its shares more than i would like to see  :Wink:

----------


## pedromartins

Hi Andy. My Apologies. My son interfered with my setup and plugged my lounge(load) into another source so I thought it was still running on battery. Redid the test and by charging the batteries on an intelligent charger separately, it only added an additional 20min. I have 1 x 110a/h and 1 x 60a/h lead acid battery in parallel. Ellies FBI1000W 600W/1000VA

----------


## ians

Andy...how is your sytem holding up...4 years since installed...they must be due for replacement?

----------


## AndyD

My system is working without problems but the batteries are now only delivering about 60% of their original capacity. Because I originally oversized the battery bank it means they still run all my, PC's, servers printers, router, phones and back-up lights for around 3 hours but unfortunately the coffee machine and a few other luxuries we had plugged in are a no go. We also have to disciplined about which lights are on otherwise back-up time would be under 3 hours. 

When the time comes I'll be looking at maybe upgrading to Lithium Ion batteries rather than like for like lead acid replacements but I'm not sure if the inverter built-in charger is compatible.

A couple of the 12VDC LED tape lights I used for emergency lights in some places have a few failed LED modules along their length but they seem to be hanging in there for now.

----------

Dave A (01-Nov-19)

----------


## ians

> My system is working without problems but the batteries are now only delivering about 60% of their original capacity. Because I originally oversized the battery bank it means they still run all my, PC's, servers printers, router, phones and back-up lights for around 3 hours but unfortunately the coffee machine and a few other luxuries we had plugged in are a no go. We also have to disciplined about which lights are on otherwise back-up time would be under 3 hours. 
> 
> When the time comes I'll be looking at maybe upgrading to Lithium Ion batteries rather than like for like lead acid replacements but I'm not sure if the inverter built-in charger is compatible.
> 
> A couple of the 12VDC LED tape lights I used for emergency lights in some places have a few failed LED modules along their length but they seem to be hanging in there for now.


Lithium is the way to go ...but man the price is still a little off the mark.

----------


## AndyD

Well we recently went through Stage 6 load shedding....thanks Eskom. In a 48 hour period we had 19 hours without power, six outages in total. Two of the outages were 4.5 hours long and four of the outages were 2.5 hours long. 

The inverter managed to handle but the batteries were almost hitting their depth of cycle limit on the second day, it was so close I got a battery safety alarm sounding for the first time ever. The problem wasn't the capacity of the batteries as such, it was that they weren't getting fully charged between load shedding events. If stage 6 shedding had continued for a third day the system would have shut down completely on it's battery protection depth of cycle settings.

Unfortunately adding batteries won't help for this scenario because charge rate was the limiting factor so I'm just going to have to hope we don't get more than 2 days of stage 6 load shedding in future. I guess trying to look on the bright side I now have a better understanding of my back-up system limitations.

----------


## SeanM

Hi Andy

The only suggestion would be solar panels to assist in the charing.

----------


## Justloadit

The cost of Lithium is dropping.
A supplier of mine has brought in a in a number of cells to make up battery packs.
He is currently offering me a 72A Lithium at a very reasonable cost, probably double the cost of an equivalent 100A Lead Acid, don't want to say here as it may be a special price to me  :Smile: 
You may be/should give him a call Mark @ SJ Andrews, not sure if he is still open due to the holiday season.

*Please note that Lithium batteries are not direct replacement for Lead Acid batteries. For safety and prevention of fires, Chargers must match the battery specifications*

----------


## AndyD

Thanks for the suggestions everyone. 

Unfortunately solar panels won't help decrease the battery charging times with my inverter. It can't use a mix of both solar and eskom power simultaneously, only one or the other. The Axpert inverter also has very specific PV string voltage requirements. A few panels might assist by supplying some power during the actual load shedding period if it was in daylight hours but for me they're not a finantially viable option with this system as it stands, installing solar panels would only be viable if I replaced my inverter with a better one with a view to feeding surplus back in for the FIT.

Thanks also for the contact but same problem with lithium batteries... compatibility issues.

When I installed this system I was under no illusions about it's capabilities or lack thereof. It was a very low budget system and at that price point I accepted the limitations it had when it came to possibilities for future expansion or redesign. I resigned myself from day one that it was going to do the job I needed it to but it was never going to be a stepping stone toward anything more extensive such as going completely or even partially off-grid with PV and it wasn't going to be very scaleable if my requirements changed much outside the original design brief.

I'm not stressed and I'm by no means disappointed, to be honest I'm actually very impressed it worked flawlessly through the 2 days of stage 6 shedding with surrounding days of stage 4 and stage 2, especially as it's almost 4 years old now. I'll probably like for like replace the deep cycle lead acid batteries when they reach their end of life but apart from that I'm just going to use it as it was originally intended and not over-spend or throw good money at it by trying to make it something it was never intended to be.

----------

Dave A (19-Dec-19)

----------


## Justloadit

> Unfortunately solar panels won't help decrease the battery charging times with my inverter. It can't use a mix of both solar and eskom power simultaneously, only one or the other. The Axpert inverter also has very specific PV string voltage requirements. A few panels might assist by supplying some power during the actual load shedding period if it was in daylight hours but for me they're not a finantially viable option with this system as it stands, installing solar panels would only be viable if I replaced my inverter with a better one with a view to feeding surplus back in for the FIT.


You can still have solar panels into a MPPT charger connected to the batteries, separate from the AXPERT, and charge your batteries during the day, with out affecting the current connection. The AXPERT would think that the batteries are charged because it would not draw current from the AXPERT, and the Voltage would be higher than what the AXPERT is expecting, and would not use ESKOM power during the day. If the batteries require charging at night, and ESKOM is available, then it would use mains to charge.




> Thanks also for the contact but same problem with lithium batteries... compatibility issues.


I have had an idea in my mind for some time now, and wondering if there is a market for it.
What if I supplied you a battery which is Lithium, but would behave as a Lead acid battery, which means that you could replace current lead acid battery pack with a Lithium pack which would appear to the AXPERT inverter as lead acid, but have the characteristics of Lithium?

----------


## ians

Found this interesting... could this be why they offer a reduction in price if you hand in your old battery... At Ra over R2000 a replacement battery for your backup system... might be worn looking into this method. 

https://www.youtube.com/watch?v=TYXx70MqJ-0

----------


## EyeGod

Hi all,

First post here, just doing some research, and since this thread has seen a lot of activity, I hoped it was the right place to ask:

I'm currently researching residential inverter installations in Cape Town, can anyone suggest someone?

I’m basically looking for a one stop shop and solution, so I would appreciate any advice you could offer.

Thanks in advance!

----------


## SeanM

Greetings

I do inverter installations in the Cape Town Area if you are interested you may contact me and I will gladly come and see you and advise.

----------


## EyeGod

> Greetings
> 
> I do inverter installations in the Cape Town Area if you are interested you may contact me and I will gladly come and see you and advise.


Hi there!

I just sent you a PM; thanks!

----------


## blackknight72

Hi Andy,

I installed a system based inspired by your write up in Feb 2015 with very similar specs using Axpert 3KV inverter and 4x Trojan T125s. As in your case the use was very minimal as ESKOM almost completely withdrew load shedding in East London. I find the system currently weak with regard to the expectations.I must confess that battery maintenance was poor as I checked the battery water levels only once that too after three years. The inverter is connected to the refrigerator and microwave in addition to the lights. Now with the refrigerator working it will be alive only for an hour or less but with minimal lights and fans it can do some 3 hours.Hence i am thinking of replacing the batteries. What is your opinion with regard to lead carbon vs existing trojan t 125s. Price wise i see no difference . Appreciate your input.

Anyone with experience with lead carbon battery is welcome to share their view. Thanking in advance.

----------


## idian makatu

Hi AndyD. I am having constant loadshadding at mi area. I want to know how can I select the solar system for my house , , to supply tv and lights Nd a fridge if possible. I want to know the size of panel can get , the battery, inverter , controller.?

----------


## AndyD

Sizing and specifying a solar system is something that needs a site visit to establish the load profile, where panels could be mounted and how efficient they're going to be with your roof angle and shading etc. You need to find someone in your area that has lots of experience in solar installations because there's no 'one size fits all' solution and many mistakes that can be made when designing these systems which usually work out very expensive. For that reason I'd strongly suggest you at least get professional advice before spending your money. 

Most respectable companies will visit your house, give you good advice and do a survey and quotation for free.

Can I ask why you want a solar system rather than just a basic battery/inverter system that just charges from Eskom power? Also out of interest what kind of budget are you working with?

----------


## AndyD

This thread is a blast from the past. 6 years on and we're still getting load shedding.....sigh.

Well a quick update. The inverter system is still exactly as I installed it, I haven't added or subtracted anything and everything still works fine.....almost.

There was one issue with a hot termination at the battery fuse holder. Luckily I smelled the hot insulation before any substantial damage occurred and I just had to cut the old lug off and crimp on a new one. There was also one string of the 12v back-up lights stopped working which turned out to be a cable that got pulled loose whilst the painters were busy in the vicinity. Apart from those minor niggles the system has performed admirably.

My present day issue is that the lead acid batteries are now at the stage where they no longer hold sufficient charge to cover a two hour load shedding. I was a bit disappointed but after looking at the date I started this thread and realising to my surprise that 6 years has gone by I guess it's to be expected. 

I toyed with the idea of replacing the batteries with lithium ion but the price is still somewhat prohibitive at around R30K for decent batteries with a good built-in management system. I'm getting quoted just under R2K for a 235AH 6V deep cycle gel battery which works out to just over R9K for the set.

----------


## blackknight72

Hello Andy, Good to hear from you!

I built my system around your input around the same time. We hardly had frequent power cuts over the last 5 years and the system was largely unused but whenever it was needed it did a fantastic job. I changed my batteries a couple of months back. This time I went with Trojan T125 Spre 255AH costing R12000 for four. From what I remember your system is also an Axpert 3KW MKS plus. Can you advise if it is possible to add one more of the same inverter to the existing one to facilitate load management?

----------


## AndyD

> Hello Andy, Good to hear from you!
> 
> I built my system around your input around the same time. We hardly had frequent power cuts over the last 5 years and the system was largely unused but whenever it was needed it did a fantastic job. I changed my batteries a couple of months back. This time I went with Trojan T125 Spre 255AH costing R12000 for four. From what I remember your system is also an Axpert 3KW MKS plus. Can you advise if it is possible to add one more of the same inverter to the existing one to facilitate load management?


Hi Blackknight, glad the thread was useful to you and it's good to hear your inverter served you well even though it wasn't needed a lot of the time. Unfortunately the old MKS Axpert inverters can't be paralleled together to run as one larger inverter like some of the newer models can.

----------


## ians

Be very careful of firmaware upgrades for these inverters.

----------


## Jaws

> I toyed with the idea of replacing the batteries with lithium ion but the price is still somewhat prohibitive at around R30K for decent batteries with a good built-in management system. I'm getting quoted just under R2K for a 235AH 6V deep cycle gel battery which works out to just over R9K for the set.


Why R30k of lithium ?

The lead acid batteries as a set will give you a rating of 5.6 kWh.  If you want them to last 5 years again you will set the DOD to 50 % so lets say 2.8 kWh @ R9k  ,  you will probably get R1k back for the old batteries at the scarp yard so R8k total

For a 10 year period, you will spend R17k on batteries

2.5 kWh Pylontech are now R13k and they will last longer than 10 years........

----------

