question

knownot avatar image
knownot asked

using swollen lipo batteries

I know the surgeon general recommends against it but I got a deal on some us2000 that had been allowed to sit discharged for some time. Cell voltage had dropped to about 1.2. I gently recharged them (c/20) to about 3.2 then hooked them up to the easysolar to finish them off. Early indications look good - no crazy self discharge, some capacity even though only half charged. Anyone else here used swollen lipo's? One pack I may no be able to put the cover back on due to the swelling - although it behaved similar to the other less swollen ones.

Pylontech
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2 Answers
wkirby avatar image
wkirby answered ·

Once the cells have been deeply discharged they will be permanently damaged. The swelling indicates severe damage and they will be almost useless because the separator is damaged.
A better option is to remove the cells and have them re-cycled and then strip the rest of the unit down for spare parts and scrap metal.

Using damaged components is kind of like driving around in a car with partially inflated tyres with no treads remaining. It will drive, but it will be dangerous and unpredictable.

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marekp avatar image marekp commented ·
@WKirby

Why scrap the boxes when you can use them after replacing just the cells. Case and internal BMS has value.

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knownot avatar image knownot commented ·
@WKirby @MarekP So I have 3 us2000 that were connected to the same failed inverter (I think fully discharged) then left for a year. In each module the 3 cell packs are very similar. One all look normal, one all slightly swelled, one all very swelled. All 9 cell packs behaved similarly electrically. For my own interest I'll bring these packs back to working voltage (supervised) and test their capacity. I know the usual outcome should be that all these batteries have very low capacity(ie. useless), but I doubt it is the case here. I'll post my findings.
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kevgermany answered ·

Hope your insurance will cover the fire this is likely to cause.

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