i got some battery's, what should i do with them ??

michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
i got a some lithium ion battery's, the good stuff,18650 Samsung 2600 mAh I've tested them they are the real deal. about 300 of them are connected together in 3 series so that gives me about 100 battery packs. i have another 200 or so that are just loose battery's, not connected together and they don't have any bms. So how would you fit them into my  system. i live in a rv so i have a 12 volt system but i really only use that for lighting the 12 volt rv system has a charger that works but the 12 volt batterys are almost dead. i have a grid tie inverter system, i produce around 5 to 7 kwh per day. one point that i would like to make is that i've been  reading a lot about lithium ion batterys and evidence is beginning to show that charging the battery to full capacity is not good for the batterys in the long run, i would like to charge the batterys to 80 percent and then use the batterys to 50 percent, i cant find a charger that will do that with a 3s battery pack system. i also have a 1000 watt 12 volt inverter that can change 12 volts dc into 110 volt ac. so anyone have advice ? best cheapest way to use these batterys ?






Comments

  • mcgivormcgivor Posts: 2,206Solar Expert ✭✭✭✭✭
    If you tested them and they are the real deal, the assumption would be that you know the chemistry, do share because it's important. Reading between the lines it would appear the cells may not be the best for the proposed application,.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

  • michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
    been a while since i tested them but what i did was charge them up to full. then i had some sort of dotad that drained the batteries and told me how many watts it took to drain them. when i get home tonight i'll get back with the name of the device.
  • michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
    i'm not sure i can post a you tube video or not, but i'll try. this is how i tested it. counterfeits are normally weaker than what they say they are. if you want to try to test your batterys this way let me give you a word of warning. that white resistor gets hot as hell. please don't touch it. one last thing, its a cheap way to test your battery, only 4 or 5 dollars.




  • michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
    holy crap, i was just looking at some of the questions and answers on this forum. you guys are geniuses. please disregard my question, i belong over in the "solar beginners corner". thank you for your time.



  • BB.BB. Posts: 27,898Super Moderators, Administrators admin
    Moving to the Beginner's Forum.

    You do need to figure out what chemistry the Li Ion cells are... LiFePO4 (lithium Iron Phosphate) are one of the "more safe" version of the Li Ion chemistries... If they are not LiFePO4 batteries, I would be very hesitant to use these in any other application where they are paralleled... If you can measure the per cell voltages when discharged/charged, you can, for the most part, ensure that they are well balanced and operating in the safe zone.

    If one (or more) of the cells becomes out of balance, that cell can be damaged or cause a spectacular failure (as in unsafe to home and humans). The "per cell" battery monitoring/control circuits are pretty close to mandatory for safety when you have series battery connections.

    A good website to visit is the Candlepower Forums... It is weighted towards flashlights and lighting, but they have a very active section on batteries too:

    https://www.candlepowerforums.com/vb/forumdisplay.php?9-Flashlight-Electronics-Batteries-Included

    And this site (he is a member of CPF) from Denmark. Lots of Battery and Battery charger tests/reviews. Also he does some detailed reviews of various Digital Multi Meters (and takes them apart)--If you are interested what is inside:

    https://lygte-info.dk/

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
    sorry i did forget to declare the chemistry:
    18650 samsung lithium ion 2600ah. strange thing about them, spec sheets say's nomial voltage is 3.8 rather than 3.7.

  • BB.BB. Posts: 27,898Super Moderators, Administrators admin
    What is the charging voltage? LiFePO4 is typically around 3.65 to 3.8 volts charging setpoint. Other Li Ion are typically 4.1 to 4.2 volts. Probably not applicable here, but there are even other chemistries that are ~2.7 volts charging setpoint. "Nominal voltage" may or may not be the charging setpoint voltage.

    Samsung makes both ~3.75 and ~4.2 volt chemistry 18650 batteries. You need the battery's model number to figure out what you have.

    Is there any marking on the battery like INR 18650 25R or ICR 1850 26F or something else?

    I am no Li Ion battery expert... Just be really careful and detailed what you do here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
    yes it has marking on it samsung icr18650 26j M
    attached is the data sheet. i have no idea where i got 3.8 from. i bought these thing back in 2017 and did alot of reading on them. seems my memory amounst other things is failing.

  • BB.BB. Posts: 27,898Super Moderators, Administrators admin
    Have you measured the per cell voltages?

    These are 4.2 volt charging chemistry batteries and need to be treated with respect.

    They can do a lot of damage if not.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • HorseflyHorsefly Posts: 310Registered Users ✭✭✭✭
    BB. said:
    Have you measured the per cell voltages?

    These are 4.2 volt charging chemistry batteries and need to be treated with respect.

    They can do a lot of damage if not.

    Bill
    +1 for what Bill says.  From what I learned back when I was trying to understand the non-LiFePO lithium chemistries, ICR name implies lithium cobalt oxide.
    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 4 x Vmax XTR12-155 12V, 155AH batteries in a 2x2 24V 310AH bank.
  • michaelleewebbmichaelleewebb Posts: 9Registered Users ✭✭
    yes i have measured the voltages and charged them up and drained them down and charged them back up to 80 percent or so.
  • BB.BB. Posts: 27,898Super Moderators, Administrators admin
    You have to measure the per cell voltage to know how to properly charge them.

    If the voltage is very low, you have to pre charge them at a relatively low current or else bad things can happen.

    Since they sat for a number of years, I worry that they may have fallen below 2.0 volts.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • davidddavidd Posts: 1Registered Users
    Hi Michaelleewebb,
    Are the loose batteries also 26jm? Would you be interested is selling me a few? I’m new to this site and haven’t figured out how to PM. Thanks,
    David
  • softdownsoftdown Posts: 1,893Solar Expert ✭✭✭✭
    Not sure but I have a vague memory that cobalt batteries are higher performance/more expensive. Lithium batteries are no toys, they can be toxic if burning. Should have value somewhere. Inside a home though?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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