Recently I negelected to unplug my kokam 3s2p (3000 maH) battery pack from the ESC (the switch was off, must've been the BEC) for ~10 hrs. When I realized what I had done, I unplugged it and checked the voltage it read 2.5 volts. I placed it in a pyrex dish with a lid outside and checked the voltage the next morning. The voltage was back up to 6.3 volts. There is no swelling, smell, or oozing. I am wondering if anyone has any info on how I may be able to save this pack. Is it worth trying to coax the pack back up to 9 volts by charging it at 0.1 C? Any help would be appreciated.

Thanks,


Matt

Your pack will probably be OK. Since the voltage was low but not totally flat, and for a short time, I'd recommend charging it at the 0.1C rate as you thought. Do it in a safe place and monitor it but do it soon. The longer the battery stays below the minimum of 3V per cell the greater the risk of permanent damage due to chemical reaction. You may find that it has lost some capacity but only testing will tell.

Also, since it is a 3s pack you need to check for cell imbalance between cells in series. Such a low discharge can cause the cells in series to discharge to different voltages. If your pack is assembled as a single shrink-wrapped unit then the only way to test for this will be to remove the shrink wrap so you can get to the individual cell connections to test the voltage with a volt meter. If the cells are imbalanced you will need to charge each group of paralleled cells separately to a maximum of 4.2V per paralleled set.