Battery recuperation

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lazza
lazza Solar Expert Posts: 336 ✭✭✭
in Off Grid Solar & Battery Systems #1
HI Forum

I've recently seen some 1200Ah C100 batteries that have been left idle for a couple of years. They look new, and of course I know that it is a death sentence for any battery to be left discharged for any length of time. Each cell was giving between 1.1V and 1.4V.

I was just wondering if there are any methods for trying to revive batteries in such a state? Some kind of boost charge to displace the sulphation??

Any advice appreciated

Thanks
Larry

ps sorry for being off the forum for so long... been busy with installations and havent until now found anything mysterious.. all pretty run-of-the mill and no problems. must be getting better:)
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Battery recuperation

    No.

    Dead batteries are dead batteries and can't be brought back to life. They are scrap.
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #3
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    Re: Battery recuperation

    Had you gotten to them in time, it may have been possible, yet the likelyhood of being scrap is now very high.

    If the timeframe was much shorter, revival usually means a bench supply, and applying no more than .01C at low voltage. When the voltage starts rising a little bit, you apply a little more current, and many more hours of watching and waiting and repeating until it reaches a normal voltage upon which you can apply full current again.

    Basically a LOT of work to end up with questionable cells afterwards. Yep, scrap. :)
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  • lazza
    lazza Solar Expert Posts: 336 ✭✭✭
    #4
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    Re: Battery recuperation

    Well, the more i learn about batteries the more i think that's it's a kind of magic.

    Having revised the installation after putting a system that gives around 40A to the 1200Ah C100 batteries in a 24V system in an attempt by the owner to revive them.. well it appears they've recovered!

    6 of the 2V batteries had had some kind of charge in the last 2 years, and had been giving around 1.9V per cell before recovery. The other 6, which were the ones i referred to in post had been left for dead... with voltages as low as 1.1V, max 1.4V.

    But now, with them all in series after a month or two of a modest charge, they are all giving more or less equal voltages, for example, at 2.25V in flotation.... performing well and looking great. :p

    So, are battery fairies real? How do I invoke them in the future? Can the same trick be used to banish battery gremlins in less fortunate systems?
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #5
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    Re: Battery recuperation
    lazza wrote: »
    But now, with them all in series after a month or two of a modest charge, they are all giving more or less equal voltages, for example, at 2.25V in flotation.... performing well and looking great. :p

    I'm not too impressed with the voltage recovery... even a badly sulfated battery can have normal voltage. If they are performing well, that's what counts!

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    #6
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    Re: Battery recuperation
    lazza wrote: »
    Well, the more i learn about batteries the more i think that's it's a kind of magic.

    Having revised the installation after putting a system that gives around 40A to the 1200Ah C100 batteries in a 24V system in an attempt by the owner to revive them.. well it appears they've recovered!

    6 of the 2V batteries had had some kind of charge in the last 2 years, and had been giving around 1.9V per cell before recovery. The other 6, which were the ones i referred to in post had been left for dead... with voltages as low as 1.1V, max 1.4V.

    But now, with them all in series after a month or two of a modest charge, they are all giving more or less equal voltages, for example, at 2.25V in flotation.... performing well and looking great. :p

    So, are battery fairies real? How do I invoke them in the future? Can the same trick be used to banish battery gremlins in less fortunate systems?

    Wow I love hearing stories like this!

    How do you know they are performing well?
    Have you performed a discharge test?
    How do they perform under a sustained heavy load?

    If you could perform a discharge test applying a load of say C/5 or C/10 over an hour or two and publish the results I'd be very grateful to see it!

    D
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  • lazza
    lazza Solar Expert Posts: 336 ✭✭✭
    #7
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    Re: Battery recuperation

    HI, will do if I get the chance- would have to get permission of the owner. I know he has a fridge working and puts the microwave and toaster on with no problem. Not the same as a C5 discharge of course.

    Will keep you posted
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
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    Re: Battery recuperation
    lazza wrote: »
    HI, will do if I get the chance- would have to get permission of the owner. I know he has a fridge working and puts the microwave and toaster on with no problem. Not the same as a C5 discharge of course.

    Will keep you posted

    Especially not if done during the day while the PV is producing power.
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