On May 31, 10:33*am, "
wrote:
On Thu, 31 May 2012 07:59:10 -0700 (PDT), harry wrote:
On May 30, 10:47*pm, SMS wrote:
In 1972, Popular Electronics had an article about how to fix NiCad
batteries that had developed an internal short and would not take a
charge. Last week I had two Dewalt battery packs (6 batteries in each)
that wouldn't charge (charger gave the fast blink error). I hauled out
my high-current power supply and zapped each cell 20 times. The packs
both work fine now.

Note that you have to disassemble the battery pack to zap Ni-Cads
because you must zap each individual cell, not the entire pack at once..
Also this is not for NiMH cells or Li-Ion cells, only NiCad cells.

"Whiskers" of cadmium metal short the cells out.
Zapping them just blows the whiskers apart.

Since the whisker grew in the first place, it'll grow right back.

Sometimes works.

Sometimes. *For a short time. *Bottom line; replace the cells.

If you can keep the battery pack on a constant ;low charge, that will
usually prevent the wiskers from forming a real short, it apparantly
burns them off oas the just get to the shorting point. But if no
constant charging, then good luck.