Dead LiPo Battery Hack

[Kato]

Had a SuperB battery sitting on my desk basically being a paperweight for the past couple of years, took it out of the bike after I neglected it, and it went so flat that it would not accept a charge, should have binned it not sure why I didn't, anyhow this week, somebody told me that they had a little trick with LiPo batteries, and today I tried said trick.

I put a meter on the battery just out of curiosity, and it was showing 1.2 volt tried it on the charger nothing doing, so with a second good battery I connected the two together minus to minus plus to plus for 30 seconds (i'm advised never more than 35 seconds)

OK so put it back on the charger and the thing starts charging it's now full, so I'll monitor for the next couple of days but if it now holds its charge I'm very happy as that's just saved me £250 for a new one

[Kato]

And I can report that it deffinately works.

Have had the battery sitting on the bench now for two days, check it pretty much whenever I walk past and has been holding a steady 12.64 volts, in my book thats job done

[Davy]

Great when things like this happen bet you grinning from ear to ear.

[Nickj]

Why you need to start out with a parallel charge is because most smart chargers won't charge a LiPo if the base volts per cell is less than 3V. The reason is simply liability.
The cells internal resistance rises dramatically which means it can get very hot very quickly, hence the 30 seconds. Once you get to 3V then your smart charger will start to work again and let you charge the battery.
The caveats are that you may be left with a cell or two that can be unstable in terms of discharge. That is the cell can drop charge really quickly and get very hot. In the packs I use I'll be able to see the signs that indicate a cell is problematic, slight swelling, small surface blister but in a sealed cell system that's all hidden.
Battery packs recovered like this (I do have a few) are generally viewed with a fair bit of suspicion and definitely NOT used where there might be a heavy discharge rate. They'll hold charge just fine but it's when they start to get that hard discharge that things can suddenly go very pear shaped very quickly.
I wouldn't use any of the recovered LiPo's I have in say my RC heli, there's too many delicate and expensive parts depending on a stable and flame free battery when I'm pulling 100+Amps from the cell pack .. I'd rather buy another than kill £1000 worth of toy