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  1. M

    Top balancing 280ah REPT cells is one cell bad?

    I see you're asking him but personally I discharged using the tester with the fan/heatsink on it, at.. 17 amps if i remember correctly? So that would be under .1C on the 280, i think (new to all this). My test on the potentially bad cell came out to over 280 amp hours. I think I stopped the...
  2. M

    Are my panels broken? My charge controller? Low wattage..

    I am realizing that solar panels are a more flexible affair than I had previously thought. If I can get 90% efficiency out of the panels then I would be satisfied, but at 45% I figure I have work to do. After I make the modification to the temperature settings that Substrate mentioned above...
  3. M

    Are my panels broken? My charge controller? Low wattage..

    Good information, I am still digesting much of it. Your idea about connecting two lead acids in series is brilliant and I think something I can do. So the method would be to take two 12v lead acid batteries to a lower SOC, then, series connect them to achieve approximately 24-26 volts. Then I...
  4. M

    Are my panels broken? My charge controller? Low wattage..

    Update: After having read your provided thread, I will be changing gears in my diagnostic method due to the complexity of panel diagnostics. I was of the mind to try to rule out the panels as a failure point first so that I could then diagnose the charge controller and wiring. Instead, now I...
  5. M

    Are my panels broken? My charge controller? Low wattage..

    In order: Yes I did say I'm reading about 31 volts open current (if i understand open current correctly), perhaps as much as 33. The Voc rating is 37.8 V. Can you tell me, I take it voc means when there is no load on the panels, just the wires voltage being tested straight out of the panels...
  6. M

    Are my panels broken? My charge controller? Low wattage..

    For a point blank question, perhaps someone who knows can answer.. If a panel is rated for 30.8 volts, and a multimeter shows 31 volts on the panel and.. A panel is rated for a current of 8.5 amps, and a multimeter shows a short circuit amps of 7.5 (sun at slight angle, a little dirt on the...
  7. M

    Are my panels broken? My charge controller? Low wattage..

    This is very helpful, and thank you. I think you are absolutely correct. I have not yet connected the temperature sensor. I am wondering if this and the setting you mention are part of it. I have an update, which is that I significantly shortened the 14awg CCA wire from the solar panel, and...
  8. M

    Are my panels broken? My charge controller? Low wattage..

    Because I discharged the battery at about 40 amps for about 4+ hours, it has no constant charging source at this time (solar is not connected yet, doing testing when I am present at the location). I don't have a pic handy, no. I may be able to get one uploaded in the next couple of days...
  9. M

    Are my panels broken? My charge controller? Low wattage..

    That's the charging voltage, sorry, and it's a guesstimate of the voltage because that's the only number I didn't make note of. My battery is definitely at low SOC, and adding a large load to the battery makes no difference whatsoever. Believe me when I say that the voltage/amperages that we're...
  10. M

    Are my panels broken? My charge controller? Low wattage..

    Hi, I have two 260 watt panels, paralleled to a 40 amps epever tracerBN(mppt), connected to a diy 280ah lifepo4 battery. The battery is at a low SOC, it's a sunny California day at around noon. I'm getting 17 amps max :-\ I check the voltage at the panels, it reads approx 31 volts. (Vmpp =...
  11. M

    Exliporc 280Ah REPT batteries received 6-24-2021

    My time was right at 60 days and I'm near the port. My tracking as well had no change until I received the items. To be clear I ordered from Shenzen Starmax not Exi..
  12. M

    Bait and Switch AliExpress

    But alas I won't stay up too late on this topic, I'll only recommend a short read. "The benevolent nature of capitalism" I think it's a buck on Amazon. Time to counter some of that Marxist indoctrination you absorbed during college fellas, really. The doorbell is ringing and it ain't pretty ;-)
  13. M

    Bait and Switch AliExpress

    How do I know? because capitalism existed before corporations, and is independent of them. Technically it's independent of government too, innit?
  14. M

    Bait and Switch AliExpress

    Capitalism is not corporations controlling government.
  15. M

    Bait and Switch AliExpress

    Yes, and through the wall of regulations that has been built up slowly over time to absolutely suffocate small business. (Upon taking on a single employee you basically have to hire an accountant/lawyer for all the paperwork involved not to mention workers comp medical etc. etc.). That wall of...
  16. M

    Bait and Switch AliExpress

    Capitalism is NOT "selling off our manufacturing industry to china at the behest of the lobbying industry (corporations)" that, is actually government working hand in hand with business, a.k.a. Fascism. What we have in America is not capitalism, but "crony capitalism". Big difference. Almost...
  17. M

    Bait and Switch AliExpress

    Except in America we joke about the used car dealer (that way of doing business).
  18. M

    EVE 280 Ah from Shenzen Basen are not "brand new" as advertised

    I've got the REPT 280ah from Shenzen Starmax. I've got a couple cells with a couple dimple sized dents, some variations in settling voltage, and some of the "laser welded terminals" look a little rough, but with that said I am fairly pleased with the product. I tested the cell that fell the...
  19. M

    Exliporc 280Ah REPT batteries received 6-24-2021

    You are right, and it may be said that when the Phoenix rose from the ashes, it was heaven's will.
  20. M

    Exliporc 280Ah REPT batteries received 6-24-2021

    It is well known to us gai-jin that some business practices considered acceptable in China are seen as unethical by American standards.
  21. M

    Exliporc 280Ah REPT batteries received 6-24-2021

    So do we call this a shameless plug, or.. do we say something like leave the paid shilling to Amazon.. My REPT cells have no qr code, and the voltages were not completely exact. So far they are testing well, but they are grade B+ cells.. My guess is if you order them, yours will be too. Pay...
  22. M

    Top balancing 280ah REPT cells is one cell bad?

    So I charged it back up, and it did indeed behave the same. I have received the bms but haven't added that cell to pack yet. I have the capacity tester Will recommends coming in tonight so I should be able to test that one cell by itself. I have to say now that I've built my first pack (yay)...
  23. M

    Top Balancing "How to"

    Just dropped in the last couple pages, my mistake if this has been answered but.. You did set the voltage at the PSU (and confirm with multimeter) BEFORE you connected to your cells, right?
  24. M

    Top balancing 280ah REPT cells is one cell bad?

    I'm waiting on BMS to arrive. So not yet. but doesn't that massive difference in voltage indicate something.. bad? (total newb)
  25. M

    Top balancing 280ah REPT cells is one cell bad?

    So I top balanced a group of 16 280ah REPT cells from Starmax to about 3.62v. Left them connected in parallel for a couple days after charging. After balancing the voltages have settled down to the 3.46 range, and are all very very close, 3.461-3.469 except one! One cell is reading 3.37x and...
  26. M

    Top balance grade A brand new cells that are all at exactly the same voltage?

    Gotta do the quasi-necro on this thread. Ontheroadagain (great track btw) is correct in that "it would be nice" if there were a simple, cheap, recommended bms or voltage limiting device that made the top balancing process fool proof. As a beginner to lifepo4 diy, I will say that if that...
  27. M

    any fix for shattered glass?

    Epoxy is very tough. Easily stronger and more durable than any original glass (it would not shatter). It is commonly used on floors, and with even a thin layer properly applied it is stronger in many ways than wood. I've used it to reinforce compromised ply by diluting it with xylene and...
  28. M

    Cheapest DIY 12V 100Ah LiFePO4 battery build? 60Ah?

    Thank you. Could I go with wire connection? I may be wrong but since the batteries are already 12v each, and I want to stay at 12v, I would need parallel, not series, right?
  29. M

    Cheapest DIY 12V 100Ah LiFePO4 battery build? 60Ah?

    Total newb here, thanks for bearing with me.. Regarding those miady 16ah batteries, with seven in parallel yielding 100ah, would the parallel set up be able to connect to say a 1500w pure sine inverter? The terminal tabs are small, so what run low gauge wire to parallel them and then tap in to...
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