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tetrasection

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Everything posted by tetrasection

  1. Must be 2.5mm2... If you connect the panels in series using your current cable you will get around 4.32V voltage drop. which is 4.8% power loss. So your panel Voc in series will be 90V minus the 4.32V your sitting at about 85V Voc. I would say that is plenty far enough away from the 100V max. Alternatively, if you buy 2x 20m of 6mm2 cable and connect them in parallel you will get 3.6V voltage drop which (at 45V) is 8% power loss. So even with the thicker cable you will be loosing almost double as much power than connecting in series. Also, these voltage drop calculations are based on Voc. Since you will actually be seeing Vmp when the sun is shining on them, the percentage power loss will be even higher. If you want to get power loss comparable to connecting them series but with a parallel connection, you will need at least 10mm2 cable.
  2. Your batteries don't feed into your house wire, they feed into your inverter. 60A battery discharge goes together with your battery voltage which is around 50V. So 60A x 50V is a max discharge of around 3000W. Once that get's converted to 220V the current will be below 14A (3000W / 220V). 63A at 220V would be over 250A battery discharge... 60A x 50V = 3kw 3kw x 2 hours = 6kwh How can you charge a 20kwh battery bank with 6kwh? EDIT: I'm talking only about the battery charge/discharge settings here, not the inverter AC output current setting (which should not go higher than 60A).
  3. What mm2 cable do you currently have?
  4. On that subject, say your output voltage is 14V, is it more efficient to have a 28V input or a 25V input? In other words is it more efficient when it only has to halve the voltage compared to more "complex" transformations, even though 25V is closer to 14V than 28V is?
  5. The operating voltage as I understand it in this case is the MPPT operating voltage, so that would correspond more to Vmp. The manual specifically says max Voc is 100V, so if his panels are 90V Voc it is below the limit and within the usage parameters. As such if anything does go wrong he is well within his rights to claim warranty. However, generally it is recommended to stay at 80% or below maximum specifications. The US electrical code even requires that you multiply the Voc by 1.25 before matching it to the inverter's max Voc. I do not know if such regulations exist in SA though...
  6. Also, the proper way to balance cells in parallel is as follows: 1. If possible - top each of the cells up to the voltage of the highest cell prior to wiring them in parallel. 2. Wire the cells in parallel 3. Set the power supply to 3.40V and the amperage to about 80% of the max it can do. (Setting it at 80% is only to prolong the life of the Power Supply) 4. Turn on power supply and charge to 3.40V 5. When the current has dropped to 0.0A at 3.40V turn off the power supply & set it to 3.50V 6. Turn on power supply and charge cells to 3.50V 7. When current has dropped to 0.0A at 3.50V turn off the power supply & set to 3.60V 8. Allow current to drop to 0.0A at 3.60V 9. Disconnect Power. 10. The Battery pack is now perfectly balanced.
  7. I can't say for sure but it shouldn't be too much. I would also series those panels.
  8. Note they said "best" Vmp range, not min and max Vmp range. That's because the system/battery voltage is 12V. So if your charging voltage is 14V and your panels are tracking at 15V the charge controller barely has to do any work and you get max efficiency. The higher your tracking, the more work it has to do to step down the incoming voltage, so your efficiency gets lower.
  9. He is talking about something like this: https://www.builders.co.za/Garden-%26-Pets/Watering-%26-Irrigation/Irrigation-Pumps/60L-Horizontal-Hidrosphere-Pressure-Tank/p/000000000000632386 It's basically a tank with an expanding rubber balloon inside. That way when the pump is off the water still stays pressurized. So normally you would run the tap at a low flow rate and the pump would be on the entire time. With a pressure tank, you can use the tap for a long time (I think it's about 30% of the tank volume depending on pump pressure rating) before the pressure gets low and the pump has to turn on. When the pump does turn on it only has to refill the tank, and because the flow isn't being restricted it will fill up in very a short time. I also highly recommend getting a pressure tank. Saves a lot of power and reduces wear on your pump. Also, if you fill it in the evening it doesn't matter if your batteries run low because you won't need to run the pump (which can cause a voltage drop and cut the power).
  10. Balancing by parallel will take ages and while you might balance the voltages eventually, the cells will not magically be matched, so as soon as you discharge them they will become unbalanced again. The whole topic is how to balance without a charger... But yes... they balance easier while charging, but then you still need a balancer. Otherwise you have to dismantle your pack and put it in parallel every time you want to charge your batteries.
  11. Ok that's a lot! In that case I would drive to their offices and speak to someone directly.
  12. Slow balancing. Imagine charging your batteries with 2500W of panels, you'll get about 50A of current, divided by your 14s batteries is around 3.6A per battery. So in that scenario the balancing current would be less than 1% of the charging current. Might be fine for brand new matched cells but if your cells are even a bit unbalanced I highly doubt that would be enough to balance them during a single charge cycle. So I personally would add a cell balancer to this BMS. You get 14s balancers like the one I linked to in your other thread do 0-5.5A balancing, basically the bigger the imbalance the more current it supplies.
  13. Yeah it seems the new higher wattage panels coming out these days are all higher than 9A... Found 250W panels here than have an isc of 8.86V: https://protonsolardistributors.co.za/solar-panels/poly-panels/250w-24-panel-detail You could have up to 12 of these connected in series for a total of 24 panels.
  14. I personally would go with option 2 because the panels will be perfectly matched plus you will get the highest voltage which will lessen the effect of voltage drop in your cables. Also, if your current setup is 115.8V 18.2A then doubling up would give you 115.8V 36.4A, not 27.3A...
  15. That means it only starts balancing when the voltage of one of the batteries reaches above 3.50V and stops balancing when below 3.50V Problem with these BMS's is the balancing current is tiny, only 0.03A...
  16. If possible I would move the pool panel to the north and then have east/west for the solar.
  17. In my experience you will never get your deposit back from these people so just stop paying your bill and they will eventually cut you off. Then just ignore them and after a while they will stop bothering you.
  18. Yeah I know but that's with DHL. Alternatively you're looking at a 6-12 month wait the way things are with the post office these days...
  19. Yeah then go with 6 inverters each with their own panels and batteries. With 6x 8kw inverters you can use around 80kw of panels so you should be good.
  20. My manual is for the Powerbox which is the same batteries just put into a case but that would explain the version difference. Yeah it says ES, and on the Growatt website the only inverters with ES in the name are the SPF3000ES, the SPF5000ES and the SPF3000LVM-ES which is the low voltage version but otherwise identical.
  21. My manual (version 1.2, dated 28/06/2020) says: 0010 for Growatt HVM, ES and WPV on CAN 0100 for Growatt SPH and SPA on CAN 0110 for Growatt SPF, HVM-P, ES and WPV on RS485
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