Restoring Cordless Drill NiCd batteries

[vcoleiro1]

Got a Bosch 12V Cordless drill the other day for nothing. Took it home and the battery would not charge at all. 0 Volts showing on the Multimeter .  I wondered if there was some way it could be restored to take charge again and did some googling.  

 

I found the video below which basically involved attaching a wire from the (-) terminal of another 24V battery I had to the (-) of the dead 12V battery.  You attach another wire to the (+) of the 24V battery and then make quick contacts with the (+) of the 12V battery for about 6 seconds.   After doing this you should notice the battery has a voltage again. IF its worked which it did for me first go, you should be able to charge the battery normally. 

 

Worked a treat for me, saved me about $40 for a new battery. Although be warned, there is risk I'd imagine. 

 

http://www.youtube.com/watch?v=yvpGp2CM-qk

 

[Wally]

From what I understand the NiCd Crystallises at the contacts.. All the voltage does is force those crystals to drop down. You're not going to get 100% back out of it due to the crystallisation but its good it holds charge at least! 

 

[vcoleiro1]

Seems to be holding a decent amount of charge for the moment, we'll see how it goes long term.

 

[Wally]

Yeah you'll be right until it crystallises again

 

[vcoleiro1]

I think it probably crystalized because it was left flat for a long time, so hopefully if I keep using it this time, it might be right.

 

[elwing]

I guess the most important point is to make sure it's a NiCd cell... I imagine doing the same with any Lithium Ion would be quite a bad idea...