Zapping Laptop batteries

From: Gary Hildebrand <ghldbrd_at_ccp.com>
Date: Fri Nov 15 08:08:00 2002

Lawrence Walker wrote:
>
> This has come up before but I can't remember it being resolved.
> I often see suggestions for rejuvenating failed or dying laptop batteries using
> a hi-amp source to flash them and break down the built-up crystals.

What really happens is that minute 'hairs' grow from terminal to
terminal in the cell, effectively shorting it out. To remove them
requires a flash of current to 'burn' them out. Either a high current
source (10A or more) or a large capacitor discharged into the cell does
the job.

> Most mention breaking the pack apart before doing this individually on each
> cell. Is this because each cell might have different resistances ?

No, each cell has to be individually zapped if shorted. If the cell
isn't shorted, you don't zap it.

> Most of my LT batteries no longer work anyway so it would be no big loss if it totalled
> them. Sending a dozen or so batteries into a rebuild place is a costeffective
> non-option and replacing the individual cells would still be costly.

My experience has shown me that doing this only extends life for a very
short time, maybe a few months at best, when the symptoms return. By
then the battery pack has pretty much run its lifespan. If your nicad
pack has standard AA/C/D cells, rebuilding is a way around it, but most
packs now have odd-sized cells, so the cost skyrockets there.

If it were my laptop, I'd just spend the money for a new battery.

Gary Hildebrand
St. Joseph, MO
Received on Fri Nov 15 2002 - 08:08:00 GMT