Batteries Lipo Ressurection

[bigone5500]

So I got this broken safety light from work. It has all kinds of jumbo LEDs inside that flash in a safety pattern. Somehow somebody took out some serious fury on it. The outer case was ransacked. The PCB was demolished. But the 1s 1300mAh lipo was in tact. I salvaged it and brought it home. When I checked the voltage it read millivolts. I guess some water must have gotten to the board and caused the cell to completely discharge. So I read online where you can set the charger to NiMh and charge it at 100mA to 3v then shut it off and charge normally. Initially the cell would not do anything on the charger but after charging on NiMh mode, the LiPo mode now works. So I set the charger to 1.3A rate and away it goes! So far it's at 42 minutes and has charged 685mA of current into the battery. It's at .4A charge rate currently and everything looks good. The cell shows no signs of puffing and isn't hot. Sure be nice to get a free lipo...for what it's worth...

 

[bigone5500]

Ok. Just after posting this thread, I checked the battery and felt of it to see if it was warm. It was not. However, I noticed that when I squeezed it a little, the charge current went up from .4A to .6A.

Does this mean the cell layers may be damaged?

 

[Smoggie]

If the battery has been down at almost zero volts for a good while then it's toast. You may well be able to get some charge into it but it wont be usable, even if you do get it to charge up fully it's internal resistance will be through the roof making it no use for RC motor applications. By all means give it a try though but I I'm pretty sure you wont have any luck.

Batteries that have not been quite so deeply discharged and/or havent been low for long have a decent chance of recovery.

 

[bigone5500]

I connected this battery to a small brushed quad motor with prop and run it for a couple minutes. The current draw was about 3A. I'm doing a 2C charge to see what happens.

 

[bigone5500]

The battery started out on 2400mA charge but quickly lowered to 1A. It's been charging for about 23 minutes now and 300mA of charge has went in. I'll connect it to something and see what the outcome will be...Maybe a small quad.

 

[Tony]

Connect it to a high amp draw motor. Break that sucker back in correctly! Of course you will not have to worry about that battery after the fact and you might want to do this test in a fireplace....