Solar panel design and installation

[Isetech]

This is where I got the information... one of the many Sunsynk training documents I have been reading since the beginning of 2022.

If you link 2 strings in parallel, they must be identical, but you can mix panels between MPPT's.

Copy and paste:

WARNING:

If the voltage is too high on the MPPT, you can burn out the front-end. DC to DC converter damaging also invalidates your warranty. Keep your Voc below 450V.

Regardless of the power of the solar panel, the inverter will only draw what it needs (basic ohms law).

Please refer to our training manual part one. When wiring to strings in parallel, please make sure the strings have identical power, identical size, and identical manufacturer. Do not mix panels if one string is only 8 panels and the other 9. This will create an imbalance and cause major efficiency losses. However, you can mix panels between the MPPTs since both inputs work independently.

[Isetech]

Important to take note of this:

6.1. WIRING PRINCIPLES In photovoltaic systems, the panels can be associated to generate more power, forming arrays. The modules can be connected in series or parallel depending on the application. When modules are associated in series, the total voltage increases and the current is the same. On the other hand, when modules are associated in parallel, the voltage is the same, but the total current is the sum of all currents.

What this means is that the 2+2 for the Sunsynk inverter the first 2 (string 1 and 1.1) will be connected in parallel and must be exactly the same. If you have 4 x 545 watt panels in string one, then string 1.1 must also have the identical panels. 4 x 545 watt panels.

the second 2 can also have 2 strings in parallel string 2 has 8 x 545 watt and string 2.1 must also have 8 x 545 watt

When the 8 panels are connected in series the voltage (49.75 VDC x 8) will add up but the current stays the same 13 amp, as soon as you put the 2 in parallel then the voltage stays (398 VDC) the same and current (13 x 2) adds up.

[GCE]

So you need to push as much power back into the grid to recover these cost. Having 6 panels on the roof with an 8 kw unit was a nice load shedding solutions, to top up your batteries without using the grid power, but will become a waste of money once they force you to register your system.

Just think if you install a 16 kw unit x R143.75 = R2300 monthly charge, with a feed back tarriff of only around R1.40 , you gonna need a lot of panels.

You may get a surprise using the above logic
Nersa restricts to 25% of CB size being allowed to feed back and at the end of the day municipalities are going to have to restrict feed back to enable transformers to stay loaded at at least 25% of capacity otherwise the network will be unstable.

If you look at Cape Town there is a limit to the amount of people that can feed back

[Derlyn]

It seems a bit one sided that the feedback is limited to 25% of the breaker size, the reason for which I fully understand, but the charges are calculated purely on the inverter size and do not take the breaker size into account.

[GCE]

It seems a bit one sided that the feedback is limited to 25% of the breaker size, the reason for which I fully understand, but the charges are calculated purely on the inverter size and do not take the breaker size into account.

So far I have only heard of KZN (from Isetech) charging per inverter Kw - In PE it is a str availability charge of R147 + vat and they will only zero on units used/fed back in the same month and there is a stipulation of same time period , in other words peak for peak or off peak for off peak

I would think that KZN will also only zero on KW used not on availability charge

Cape town they way I understand is also only on KWH used that feedback will credit - Availability stays fixed and not everyone will be able to get "cash back" for feeding excess , that is a separate issue - I am under correction

[Derlyn]

@GCE

Do I understand you correctly ?

If I were in PE and lets say, hypothetically, I install a system big enough to supply my needs without having to use any mains power, my monthly availability fee will be R147 + vat irrespective of the size of my system.

I'm only using this hypothetical example to understand the system used for availability charges.

[GCE]

@GCE

Do I understand you correctly ?

If I were in PE and lets say, hypothetically, I install a system big enough to supply my needs without having to use any mains power, my monthly availability fee will be R147 + vat irrespective of the size of my system.

I'm only using this hypothetical example to understand the system used for availability charges.

Correct
I sit at my office with that account - I imported 70 units and exported 89 at peak rates which nullified the import and just paid availability for the month - Install the system in 2014 upgraded battery to a Tesla in 2019

We set up the inverters to fed back into the grid during peak times as the rate to fed is higher than what we use in off peak times to charge the battery

I have a client that uses 600Kwh , Buys 212Kwh at off peak , sells 462 KWH back to grid mainly peak and month end elec bill is R 147 + vat

PE is way ahead when it comes to rates etc - Only problem is that there is a back log of over a year for meters from them so sitting with frustrated clients , one of them being me for home.

[Derlyn]

Thank you GCE.

That sounds fair enough.

If that's how it works then it makes sense to install something that will deliver as close as possible to one's overall needs, or maybe a bit more and still have the availability of munic power for battery charging during the bad solar periods.

[Isetech]

Let me start by saying, I haven't personally registered a system yet. It is a lot of hear say.

It seems at this point in time there is a lot of speculation, I am not aware of one domestic installation that has been registered, complete with the correct meter.

I am not aware of any public awareness programs currently running to educate the public on how what to do with a solar system of their property.

I have noticed there has been an upgrade to the website.

https://www.durban.gov.za/pages/residents/energy-office

Trying to figure out what to do is like a maize for me at the moment, just imagine what it must be like for the man on the street trying to figure out what to do.

It is time to employ a person to manage registrations, this is going to become big business. I dont have time to try figure out what is going on, the website keeps updating, unless you follow it on a daily basis, it will be difficult to keep up. I have around 15 site that require registration.

[Isetech]

Attached is the 2023/2024 (1/07/2023-31/06/2024)

With reference to scale 3/4 residential tariff

The one that affects domestic dwelling sin suburbs.

Page 14 - Feed in tariff R1.44 inc vat

What referred to as the ancillary network charge (based on the inverter per month) - R126-86 per kw. An 8 kw inverter will cost you R1014.88 per month. This is why I want to get one of the 3.5 kw units from the UK, they can handle 7 Kwp of solar, R444.01 per month That all I need for my house.

For now I believe people of eThekwini are waiting for a the council to roll out the public awareness program and hoping the grace period for registration.

I am told that there are a couple of domestic installations which are registered , but not meters to fit on their property.

https://www.durban.gov.za/storage/Documents/Service%20Tariffs/Electricity%20Tariffs/Tariffs%202023%20-%202024/Tariff%20Rates.pdf

They say load shedding will end before 2025, I see there are nuclear power plants in discussion at the moment.

I also hear comments about stage 1- 16 load shedding, its hard to believe anything, rumors spread faster than wild fires.

My aim at the moment is to get solar solar installed so that I dont have to worry about eskom or our failing electrical infrastructure and everyone I know is going large with water storage and booster pumps.

[Justloadit]

Attached is the 2023/2024 (1/07/2023-31/06/2024)


They say load shedding will end before 2025, I see there are nuclear power plants in discussion at the moment.

I also hear comments about stage 1- 16 load shedding, its hard to believe anything, rumors spread faster than wild fires.

How long does it take to build a power plant?
Nuclear reactors connected to the grid in 2022 had a median construction time of 89 months or almost 7.5 years. During the period in consideration, the median construction time for nuclear reactors was the longest for reactors connected between 1996 and 2000, at 120 months.09 Jan 2024

So the fact that they are being discussed does not mean it will clear the problem in 6 months.

[Derlyn]

Attached is the 2023/2024 (1/07/2023-31/06/2024)

With reference to scale 3/4 residential tariff

The one that affects domestic dwelling sin suburbs.

Page 14 - Feed in tariff R1.44 inc vat

What referred to as the ancillary network charge (based on the inverter per month) - R126-86 per kw. An 8 kw inverter will cost you R1014.88 per month. This is why I want to get one of the 3.5 kw units from the UK, they can handle 7 Kwp of solar, R444.01 per month That all I need for my house.

For now I believe people of eThekwini are waiting for a the council to roll out the public awareness program and hoping the grace period for registration.

I am told that there are a couple of domestic installations which are registered , but not meters to fit on their property.

https://www.durban.gov.za/storage/Documents/Service%20Tariffs/Electricity%20Tariffs/Tariffs%202023%20-%202024/Tariff%20Rates.pdf

They say load shedding will end before 2025, I see there are nuclear power plants in discussion at the moment.

I also hear comments about stage 1- 16 load shedding, its hard to believe anything, rumors spread faster than wild fires.

My aim at the moment is to get solar solar installed so that I dont have to worry about eskom or our failing electrical infrastructure and everyone I know is going large with water storage and booster pumps.

Are these rates not ONLY applicable if your system is capable of feeding back into the grid ?

What happens if you have a 5Kw plug and play inverter. Are these rates still applicable ?

[Isetech]

This is why I have decided to go all in with solar and large water tanks and booster pumps. My hooks and rails are installed.

How long does it take to build a power plant?
Nuclear reactors connected to the grid in 2022 had a median construction time of 89 months or almost 7.5 years. During the period in consideration, the median construction time for nuclear reactors was the longest for reactors connected between 1996 and 2000, at 120 months.09 Jan 2024

So the fact that they are being discussed does not mean it will clear the problem in 6 months.

[Dylboy]

Water is going to be the new thing, most people have the solar and or battery backup.

Again 2days no water for me. It happens about once a month.

The things we do to just live is crazy and get the Gov. Want their share of what they can't supply.

No wonder all my mates have left and my wife's mates and family have left the country.

Not always greener but Fuk you can live l.

Sent from my CPH2197 using Tapatalk

[Isetech]

We are on day 2 of no power, due to 2 MV faults in our area "AGAIN", we are exempt from load shedding due to flooding, the municipal strikes, road repairs (must be election time) damaging cables, you name it. Then we are told that we are back on load shedding, but load shedding is the least of our problems.

Load shedding might ease but the fact that the infrastructure is failing due to lack of maintenance, all day everyday you see people doing joints in the MV cables.

You just have to go on holiday for a week to realize how much greener it is on the other side. You just get so use to the crap you put up with here. It will never be greener anywhere for lazy people.