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  1. sunshine_eggo

    help with "large capacity" cell testing and charging

    Constant current is the most sensible as you can equate current * time to get Ah. If the discharger reports Ah, Wh, etc., it doesn't matter. If a cell datasheet specifies a specific test method, that's preferred.
  2. sunshine_eggo

    Mismatched Solar Panels for Van Build

    What PV voltage is supplied to the MPPT before it starts? So, BEFORE THE MPPT starts, i.e., NO operation at all, WHAT IS THE PV VOLTAGE? Answer that one question, and you'll finally understand. You claimed 2S PV on MPPT will get 20-30% more than 1S PV on MPPT. PWM performs 20-30% below...
  3. sunshine_eggo

    What Happens to Solar Power When Batteries Are Full

    Good points... I struggle to remember to point that out... in other words... 80% of the energy hitting the panel is being converted to heat. 20% of the energy hitting the panel is being converted to electricity. When there is no demand from the panels, simply 100% of the energy hitting the...
  4. sunshine_eggo

    Mismatched Solar Panels for Van Build

    @b33son This and flat on ground means cells are likely even hotter than they might be on the roof due to zero convection. Once you've gotten your theoretical array performance for a given condition, I'd quickly check just the 200W panel and see how its performance compares to reated for a...
  5. sunshine_eggo

    Mismatched Solar Panels for Van Build

    I have to agree with this, particularly when factoring in the crazy power disparity.
  6. sunshine_eggo

    What Happens to Solar Power When Batteries Are Full

    Why did your inverter stop pulling when the batteries were full? Your inverter provides AC from DC based on your loads. Or did you mean your AiO with built-in MPPT stopped pulling power from the array? 😁
  7. sunshine_eggo

    What Happens to Solar Power When Batteries Are Full

    Current is never pushed. It is always drawn, so the batteries are drawing the current from the MPPT up to the max it can deliver. The batteries are a load to the charger. The inverter is a load to the batteries, so the inverter draws from the batteries. It's simply a sum of sources and loads...
  8. sunshine_eggo

    Mismatched Solar Panels for Van Build

    When evaluating the configuration, if battery is nearly charged, it will throttle the panel output. To truly assess PV performance, charger must be in bulk mode, and/or you need loads > PV power.
  9. sunshine_eggo

    voltage limiting

    Voltage is not capacity. An MPPT has an output rating. It is very common to have MORE array power on an MPPT than it can ever deliver, and this can easily be done without risking exceeding Voc limits. It seems strange because you do not understand that light intensity has very little effect...
  10. sunshine_eggo

    Sun Earth panel set up.

    Energy needs are very important in deciding how much battery you need and if your solar is adequate. Even a guesstimate is better than a shoulder shrug. Figured, but us colonists don't always understand the ways of the motherland. Congrats. Nope. Panels are rated at standard conditions...
  11. sunshine_eggo

    When to know you have to equalize AGM batteries?

    100A max charge current recommended for those batteries, so you're well under that. Better to store lead acid in cold temps provided there is no risk of freezing. Colder temperature further slows the loss of charge. Yeah. Not best practices. ;) All four batteries should have been charged...
  12. sunshine_eggo

    Mismatched Solar Panels for Van Build

    Yes, those are the specs I quoted to you. Nonsensical. Why are you using Vmp? Voc applies. Not a single panel referenced has a Voc less than 21.6V. It's very possible to not understand something and draw wrong conclusions for decades. You're claiming that with nominal voltage panels...
  13. sunshine_eggo

    18 month DIY project finally done: 39kW inverter power off grid system

    I think these are down-flow cooled ejecting air at the bottom sucking in at the top, so I bet it's cold air supply with those fancy little air dams to deflect the incoming cold are into the intakes.
  14. sunshine_eggo

    Best and fastest Lifeapo4 Charger

    These are the only three that matter and for charging efficiently from battery, boost voltage is the only one that matters. You don't want to run a significant absorption or float phase on a generator as you're just burning more gas for less kWh. "Best" is too subjective. I'm very happy with...
  15. sunshine_eggo

    18 month DIY project finally done: 39kW inverter power off grid system

    Were the 18k available 18 months ago?
  16. sunshine_eggo

    Sun Earth panel set up.

    Pictures or it didn't happen. :P How many bulbs and what wattage? (y) Maybe not on that controller 88Voc on a 100V controller is a bit close. If it NEVER EVER has been below -10°C, 2S is fine, but if it has, parallel is better. If that's a Victron 100/30, congratulations! "deep cycle"...
  17. sunshine_eggo

    help with "large capacity" cell testing and charging

    3.65V @ 0.05C, so 5.25A (5 is close enough) Do not float charge. That's the opposite of stopping a charge. Many RC chargers cut off charge at 10% of start current. Yours may vary. Cells are supposed to ship at 30% SoC or lower due to hazmat requirements. Most seem to be between 30-50% in...
  18. sunshine_eggo

    Did I damage (4) Battleborn batteries?

    Looks correct with your main connects "across" all four batteries. The key is to ensure that all connections are properly torqued. What I find very disconcerting is the red cut-off switch on the PV input of the MPPT. Is your array Voc less than the rated voltage of that switch?
  19. sunshine_eggo

    Mismatched Solar Panels for Van Build

    Agree. Disagree if the small penalty is acceptable. This is just plain wrong. It's literally backwards. Parallel panels have minimal influence on each other only restricting to a common Vmp. Again, this is just plain wrong. The +5V applies to Voc, not Vmp. And in order to stay in MPPT...
  20. sunshine_eggo

    Is there a 3-imput Automatic Transfer Switch???

    I hope you understand the power requirements of an absorption fridge are 5-6X the same-size compressor fridge. A typical 7.6 cu-ft absorption fridge will use 4-5kWh/day vs. a ~18cu-ft compressor fridge at about 1.5kWh/day. Our Keystone had one of the 12 cu-ft double door fridges, and it used...
  21. sunshine_eggo

    Mismatched Solar Panels for Van Build

    STRING 1: 2X 100W in parallel, wired in series with 1 200W: 39.9 Vmp 9.8A Imp (limits 5.13A * 2 = 10.26A to 9.8A) STRING 2: In series with each other 37.4Vmp 2.94A STRING 3: In series with each other 35.8Vmp 1.96A Parallel all three strings: 35.8Vmp 9.8A + 2.94A + 1.96 Imp = 14.7A...
  22. sunshine_eggo

    Help in NM

    Just like anything else, this forum will result in GIGO... Garbage In Garbage Out. If you're not familiar with that concept, ask your wife about it. You have to give a minimum amount of information to get an answer. You're under the impression that you're asking questions that can be...
  23. sunshine_eggo

    Please help me size my mini-split for older RV

    Is it a minisplit?
  24. sunshine_eggo

    Want to use EG4 Lifepower4 48v battery for 12v travel trailer.

    30-60V to 12V, 30A: https://www.amazon.com/MGGi-Converter-Waterproof-High-Power-Transformer/dp/B07ML5ZML2 The only issue is if you have electric motors that might exceed 30A on startup.
  25. sunshine_eggo

    Mismatched Solar Panels for Van Build

    Can't make sense of that. Two rules: All parallel strings must be the same Vmp within 10%, and entire array will have penalty of that differernce. All panels in series will operate at the lowest current panel in the string. Put a 10A panel in series with a 5A panel, will work at 5A only.
  26. sunshine_eggo

    Please help me size my mini-split for older RV

    I've seen first hand how paltry RV insulation and solar load from lots of surface area sucking up that 1000W/m^2 besides just the heat transfer from interior to exterior makes A/C very ineffective; hence, my recommendation to stick with the stock size even if a 9K mini-split might suffice. I...
  27. sunshine_eggo

    Solar advice for my hot tub

    Nope. Not even close. 11.3A * 120V = 1320W a 6.5A massage blower is an electric motor (pump), so it may need as much as 30A to start (30A * 120V = 3600W). Sounds like this thing needs a 20A circuit too, not just 15A. Your inverter alone will cost more than $400. You'll need batteries unless...
  28. sunshine_eggo

    Cmax cells

    You have two options: 1) wire each module as a 3P7S "24V" battery and put a BMS on it. Then parallel the 4 batteries. 2) String a 12P7S battery across the 4 modules as described on page 1: CX = Cell 1, 2, 3, etc. YP = # of NMC cells in parallel Module 1: C1-12P, C2-9P Module 2: C2-3P...
  29. sunshine_eggo

    2000w 24 volt DIY Solar System

    No. For the few MPPT that can actually operate battery-less, the startup surge from the inverter will overload the MPPT when unattended. There may be cases where you get partial functionality. If the inverter is off, and the PV is providing absorption voltage, powering the inverter on with no...
  30. sunshine_eggo

    Please help me size my mini-split for older RV

    I don't know that I would agree with this as stated. Would the 12K be MORE efficient at 9K than the 9K? I really don't think so. Units are typically optimized for max efficiency at max output, and they tend to be less efficient at lower power settings; however, I think it will be very similar...
  31. sunshine_eggo

    Limit state of charge of GBLI 6532

    They should be at the exact same voltage as the other battery, so they will be at essentially the exact same SoC when nearing full. Are they imbalanced? If so, this is a battery issue, not a control issue. What do the cell voltages read when "full" is indicated? The BMS is in total control...
  32. sunshine_eggo

    Limit state of charge of GBLI 6532

    The BMS is controlling the inverter specifying charge voltage and maximum charge current. These values will supersede your AC charging setting if a limit is triggered, e.g., if a single cell hits OVP, it will cut charge to 0A even if it hasn't reached your 96%. There is no reason to limit...
  33. sunshine_eggo

    I'm tired of unreliable 'all in one' systems to power my fridge!

    Can you be certain the DC-DC converter can tolerate PV Voc on its output?
  34. sunshine_eggo

    Please help me size my mini-split for older RV

    IMHO, the 9K is enough. Many folks claim that mini split installation and efficiency makes them more effective than the claimed 13,500 or 15,000 BTU/h rooftop units. HOWEVER, if I was faced recovering for 3 months in the thing, I think I would go for 12K. Yes, it will be more expensive and...
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