In message , taz
writes
They tend to be "high temperature" versions (gets warm in emergency
lighting luminaires) so separator design has to be good. Dendritic
crystal growth through separators is the usual failure mode of Nicd's


--
Keith Lewis

Is that a white powdery substance. Or I'm I just
thinking of corrosion that forms on the aluminium
casing sometimes.
taz.


No its internal and causes tiny short circuits through the separator.
Eventually these raise the self-discharge rate to unmanageable
proportions ( but you will probably find that straight off charge you
still get sufficient capacity).

The cases are nickel plated steel
--
Keith Lewis