DC changeover switch

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  • Isetech
    Platinum Member

    • Mar 2022
    • 2274

    #16
    Something else to be aware of, some inverter have a 120 amp charge capacity, if your battery is a 100 amp hour 0.5 C battery the recommended charge current is only 50 amps so you need to make sure you setup the inverter correctly other wise you will destroy the battery.

    A 1C battery can charge at 100 amps, this another problem with inexperienced installers, they dont understand the battery C rating, charge and discharge rates.

    In most cases we find the installer has programmed the inverter incorrectly which has resulted in premature battery warranty claims, system only offering 10 minutes of backup, nothing wrong with the system initially, just incorrect system settings. The catch is the damage is already done.
    Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

    Comment

    • Derlyn
      Platinum Member

      • Mar 2019
      • 1748

      #17
      This is for the chaps with brains.

      So if I have 2Kw on the roof, my load doesn't exceed 1 Kw, the inverter is rated at 1,5Kw and I have 200A/h batteries, .... is that enough for stage 6 loadshedding ?

      I regard the batteries as the fuel tank, the panels as the petrol station.

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      • GCE
        Platinum Member

        • Jun 2017
        • 1473

        #18
        Originally posted by Derlyn
        This is for the chaps with brains.

        So if I have 2Kw on the roof, my load doesn't exceed 1 Kw, the inverter is rated at 1,5Kw and I have 200A/h batteries, .... is that enough for stage 6 loadshedding ?

        I regard the batteries as the fuel tank, the panels as the petrol station.
        On a good solar day and at the time when solar is producing 1 Kw , then yes - At night, No

        200Amp of batteries is +/- 2 400w of electricity stored of which you should only use a total of 30% if you want to prolong your battery ( assuming gel batteries) - You should only use 720W from your batteries during a load shed in total , so +/- 360w per hour for 2 hours

        It also depends on our charge controlling as to how quick you can recharge the batteries and your inverter charge current.

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        • Dylboy
          Gold Member

          • Jun 2020
          • 777

          #19
          Also depends on battery... Lithium fine but not SLA as they can not charge fast. They are like 0.1C. so like 10Amps max charge but they also need lots of voltage before that current can be sent.

          Lithium is amps in starfgt and a .5C of a 200 amp is 100amps so plenty plenty fast charging

          Sent from my CPH2197 using Tapatalk

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          • Thys LOW Elektries
            Silver Member

            • Jan 2021
            • 269

            #20
            Have you thought of using dc to dc charger between battery banks, also some dc-dc chargers have a solar input
            Maybe using two dc breakers to select input from battery bank output goes to buss bar and from there to inverter,
            Something like https://imgaz.staticbg.com/images/oa...0200625d72.jpg or maybe https://www.amazon.com/Blue-Sea-Syst...7365740&sr=8-7
            Just a thought

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            • Derlyn
              Platinum Member

              • Mar 2019
              • 1748

              #21
              Originally posted by GCE
              On a good solar day and at the time when solar is producing 1 Kw , then yes - At night, No

              200Amp of batteries is +/- 2 400w of electricity stored of which you should only use a total of 30% if you want to prolong your battery ( assuming gel batteries) - You should only use 720W from your batteries during a load shed in total , so +/- 360w per hour for 2 hours

              It also depends on our charge controlling as to how quick you can recharge the batteries and your inverter charge current.
              Eish ! No wonder I see houses with no tile space left for more panels and when you ask the owner if they off grid, they say 90%.

              What setup would one need to go off grid if your demand never exceeds 1Kw.

              Once again for those with some grey matter Mine has expired long ago.

              Comment

              • Isetech
                Platinum Member

                • Mar 2022
                • 2274

                #22
                Originally posted by Derlyn
                Eish ! No wonder I see houses with no tile space left for more panels and when you ask the owner if they off grid, they say 90%.

                What setup would one need to go off grid if your demand never exceeds 1Kw.

                Once again for those with some grey matter Mine has expired long ago.
                There is no such thing as going off grid unless you have a ton of cash and a generator.
                Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

                Comment

                • GCE
                  Platinum Member

                  • Jun 2017
                  • 1473

                  #23
                  Originally posted by Derlyn
                  Eish ! No wonder I see houses with no tile space left for more panels and when you ask the owner if they off grid, they say 90%.

                  What setup would one need to go off grid if your demand never exceeds 1Kw.

                  Once again for those with some grey matter Mine has expired long ago.
                  Don't think there is any definite answer , is basically how deep are your pockets.

                  To give an idea , we have a off grid system that uses 200w during the day and 1,4 Kw at night - It is all security equipment and lighting.

                  We have 10Kwp of panels and 30Kw of usable Lithium batteries - Actual sizing is 32Kw and we can go to 95% if needed .

                  Works well and generally uses about 40% of the battery and is recharged before lunch time the next day.

                  We had 2 days of rainy , cloudy weather and low solar production and on day 3 batteries turned off at about 23H00 -

                  Was +/- R 550K system which was cheaper than trying to get a cable there from mains supply.

                  I would guess that your 1 Kw system would need similar setup and then still a genset that will be compatible with charging the batteries through the inverter.
                  Inverters and generators can be a problem as you need to get the genset to run close to the inverters grid compliance figures.
                  On a complete off grid system you could widen the tolerance on the inverter if it allows you to but if you are also connect to grid you would need to satisfy NERSA requirements

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                  • Derlyn
                    Platinum Member

                    • Mar 2019
                    • 1748

                    #24
                    Thanks for that brother.
                    Thought someone would give me some good news. 😁😁

                    And Eskom wants to fix their problems with solar panels. I dont think there's enough ground in SA for that.

                    I've just ordered a stainless steel 100 litre rocket geyser. Make a small fire and half an hour later you have hot water. Plenty wood here. Back to those days I'm afraid.

                    Comment

                    • Isetech
                      Platinum Member

                      • Mar 2022
                      • 2274

                      #25
                      I have a special kettle (+/-15 litres)which fits on the gas stove, it was designed many years ago, but it never took off, I managed to get my hands on a demo unit and still use it to this day.

                      It is perfect for a bucket bath, after all the flooding it was used for a 3 weeks everyday.
                      Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

                      Comment

                      • Isetech
                        Platinum Member

                        • Mar 2022
                        • 2274

                        #26
                        I am hearing some stuff about solar and council fees and stuff that dont sound good.

                        I was holding back hoping there would be some form of rebate like they did in other parts of the world, instead it sounds like it is going to be quite the opposite.
                        Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

                        Comment

                        • Justloadit
                          Diamond Member

                          • Nov 2010
                          • 3518

                          #27
                          You need to feed the greed - the fat cats are looking for other ways to supplement their income.
                          Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
                          Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

                          Comment

                          • Isetech
                            Platinum Member

                            • Mar 2022
                            • 2274

                            #28
                            Originally posted by Justloadit
                            You need to feed the greed - the fat cats are looking for other ways to supplement their income.
                            Or carry the load of every taping in for free ?
                            Comments are my opinion, unless regulations are attached to support the comment. This is social media, not a court room.

                            Comment

                            • Dave A
                              Site Caretaker

                              • May 2006
                              • 22810

                              #29
                              Originally posted by Isetech
                              I am hearing some stuff about solar and council fees and stuff that dont sound good.

                              I was holding back hoping there would be some form of rebate like they did in other parts of the world, instead it sounds like it is going to be quite the opposite.
                              This is the reason I haven't put in solar panels for my inverter setup yet. With eThekwini's pricing structure, my utility bill will go up (quite significantly) rather than go down. Seems the safe solution is to put your geyser on solar as this doesn't carry the same prohibitive penalty.
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                              • Justloadit
                                Diamond Member

                                • Nov 2010
                                • 3518

                                #30
                                Originally posted by Dave A
                                This is the reason I haven't put in solar panels for my inverter setup yet. With eThekwini's pricing structure, my utility bill will go up (quite significantly) rather than go down. Seems the safe solution is to put your geyser on solar as this doesn't carry the same prohibitive penalty.
                                With the amount of load shedding, using a an oil based fuel for energy is getting prohibitive.
                                My experience has been that the fuel bill for 30 hours is equivalent to one months electricity bill when available.

                                The running of business is getting more expensive with every load shed cycle.
                                What is beginning to happen, is the failure of the infrastructure network with each load shed cycle, as switch gear was not designed for this type of cycling.
                                Another problem is that criminals are taking advantage of the load shed cycle to steal the infra structure.
                                Was with no power for 3 days last week due to the HV circuit breakers tripping every time they were enabled.
                                Eventually they had to rewire the substation with new wire and circuit breakers.
                                Being an industrial business area, the losses have been insurmountable.

                                Since no new power stations are being planned, the situation is not going to improve.
                                Victor - Knowledge is a blessing or a curse, your current circumstances make you decide!
                                Solar pumping, Solar Geyser & Solar Security lighting solutions - www.microsolve.co.za

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