How to repair NiCad battery packs

[techmike]

I just learned this trick, you all probably know it already. When my NiCad battery packs "go bad", get weak, won't hold a charge ect, I used to take them apart and replace the bad cells. But there is a much easier way. Evidently, some kind of crystal filaments grow in the batteries and short out the individual cells. One then needs to "zap" the battery.

1. Charge the bad pack overnight.

2. If you have a DC welder, determine which end is positive and negative.

3. Contact the negative side of the welder to the negative contact on the battery.

4. Momentarily contact the positive side of the welder to the positive side of the battery.

5. Repeat 5 or 6 times.

6. Put the battery back in the charger - it should now fast charge and operate normally.

My welder is A/C, so I made up some jumper wires and took them into work today, I used a 36 volt 200 amp fork lift battery and brought 2 battery packs back to life.

It's like magic! The voltage zap burns out the filaments.

TM

Use standard safety equipment and goggles.

[rodent.22]

yeah I ordered a dvd on e-bay for a buck that explains this whole scenario, pretty good info....

[imschur]

I had not heard this before

[Longitude Zero]

Me either.  I sure WOULD NOT try this with LiPo's.

[techmike]

It works on the NiCads - I brought a 5 year old dead one back to life - performs like a new battery. Did the other two tonight, raised 'em both from about 14.2 volts to 16.5. I also will let some one else experiment with other batteries...

TM :thumb: