Al Bundy wrote:
On Oct 9, 1:38 am, E Z Peaces wrote:
William Sommerwerck wrote:

A big killer of nickel cells is internal salts. They allow electrical
leakage so a cell won't hold a charge long and eventually can't be
charged at all. These deposits increase during trickle or C/10 charging
but apparently not with fast charging.

There are ways to burn off those salts. I suppose it might be done
with a well designed apparatus to gain a bit more life from a dead
cell, but not economically practical. For emergency purposes or as an
experiment, one can "tickle" the cell with a high voltage. I have even
used 120VAC from the wall socket. This is not for the feint of heart
and I would not advise even experimenting without proper eye and other
protection. A 12VDC battery applied to a 1.5VDC cell might be held
for about a second and no more.

In 1982, first time I saw self-discharge progress to a full short, I
zapped it with a capacitor charged to 170 V. It would take a charge
after that, but self-discharge was still high. I decided fixing shorted
NiCads wasn't worth much.