Battery capacity question

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Arkansasoffgrid
Arkansasoffgrid Solar Expert Posts: 117 ✭✭
in Off Grid Solar & Battery Systems #1
Was offered several batteries from a data storage UPS facility. They are sealed, 12v, and the only data that I can find is 280w/cell/1.67v/15min.
Initial current 28A max
3yrs old, never cycled, but removed from svc 3 months ago due to facility closure. What's the best way to test them, to be sure I am not just hauling off junk?
8-420AH US Battery L-16s, Midnite Classic 150cc, Whiz Bang Jr, Magnum MS4448PAE inverter/charger,  4590w Canadian Solar panels. Honda EU2000i generator.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    Re: Battery capacity question

    Sounds something like ~140 AH per cell. (280 WH/Cell divided by 2 volts).

    So--discharge them by 50% (~70 AH) at a C/8 (leisurely rate; 140 AH / 8 Hour rate =) or 17.5 amp rate and and them recharge them--See how they behave.

    In general, batteries designed for float service may not deep cycle very well... If you only need them to cycle by 15-25% from full--Then do that instead--They will probably last longer.

    Cycle them down to 20% state of charge--They may only do that 10 times before they croak (even if they are good batteries).

    Difficult to tell without data sheets.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #3
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    Re: Battery capacity question

    The closest I could guess is that these are HRL-12280W agm's.

    Some of the data sheets for the CSB brand show about 400-500 cycles down to 50% DOD. It looks like they were meant for, yep, super fast discharge ups service, but I suppose if they were perfectly cared for, you *might* be doing ok - maybe if you got them at no cost. Hard to tell if you are going to pay more for recycling them yourself.

    For me, they would have to be delivered to my door free of charge, wrapped with ribbon, and a guarantee of free return pickup if they didn't work out. :)
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  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    #4
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    Re: Battery capacity question

    Yea, theres a guy on the midnite forum, who went through several (literally) sets of such things, before relenting and buying a proper pack. Only do it want the aggravation/learning.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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