Mike Harrison explained :
Anyone any suggestions for getting longer life out of NiCd drill batteries.
Mine always seem to expire after a couple of years or is this normal life?
I
only use the drill every couple of weeks for perhaps 10 minutes work and
only recharge when its completely flat. When I've opened up a battery pack,
I usually find one or 2 of the 10 cells is really low on voltage, the
others being on about 1.2volts.

Geoff.

If a cell reads zero volts, it has probably dendrited - whiskers of metal
form and short the cell.
These can often be recovered by passing a very brief, heavy current (10-30
amps for a C-size cell
for a second or 2 max) through it.

The safest way is to charge up a high value capacitor (from a car
battery or similar), then discharge it across the cell to blow them
away. If you feel braver (and perhaps more foolhardy), splashing the
contacts across a car battery also works if you are quick. Make sure it
is positive to positive.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk