ModMech
Platinum Member
Yes, NiCd batteries suffer from "early" deaths due to what is commonly called "wiskers".
Wiskers form when a NiCd is left in an uncharged state, the longer they are left that way the worse it is. You can refresh them by applying a *slightly* higher voltage (3v typical for a 1.2V cell) from a source with a good charge that can deliver a few amps safely. The higher voltage will allow current to flow and the high current will burn the wiskers out (much like a 12v light bulb in a 24v circuit).
If the pack is treated well afterwards by cycling from 10% SOC to 100% SOC and back and NOT left partially charged, you can get good life back. In my recent case, 3 of the 5 cells in my MAG were "bad", I shocked the pack from my 12v motorcycle battery using a 20A fuse to prevent anything bad from happening. I got two of the cells back but the third only lasted a week and it failed again and could not be brought back.
So, the method DOES WORK but is not a 100% fix for every situation. If you have multiple packs and can try one cell at a time your chances are very good. If you have no "extra" cells and are trying to get a pack back with multiple bad cells, your chances are not as good but it can work!
Good luck!
PS: DO NOT try this with NiMh or LiOn cells!!!!!!!!!!!!!
Wiskers form when a NiCd is left in an uncharged state, the longer they are left that way the worse it is. You can refresh them by applying a *slightly* higher voltage (3v typical for a 1.2V cell) from a source with a good charge that can deliver a few amps safely. The higher voltage will allow current to flow and the high current will burn the wiskers out (much like a 12v light bulb in a 24v circuit).
If the pack is treated well afterwards by cycling from 10% SOC to 100% SOC and back and NOT left partially charged, you can get good life back. In my recent case, 3 of the 5 cells in my MAG were "bad", I shocked the pack from my 12v motorcycle battery using a 20A fuse to prevent anything bad from happening. I got two of the cells back but the third only lasted a week and it failed again and could not be brought back.
So, the method DOES WORK but is not a 100% fix for every situation. If you have multiple packs and can try one cell at a time your chances are very good. If you have no "extra" cells and are trying to get a pack back with multiple bad cells, your chances are not as good but it can work!
Good luck!
PS: DO NOT try this with NiMh or LiOn cells!!!!!!!!!!!!!