On Wed, 1 Aug 2012 06:38:54 -0700 (PDT), "hr(bob) "
wrote:

On Aug 1, 7:39*am, "John Grabowski" wrote:
Is it best to run an 18v battery completely dead before recharging??
Or should I recharge it when it's low but not completely dead? *This
would be one of those Black & Decker batteries for all their battery
operated tools.

*You should check the tool manual for charging. *It varies according to the
type of battery. *I bought a Porter Cable drill last year with NiCad
batteries which I had always thought needed to be run down before charging.
However according to the manual the batteries can be recharged at any time.

The old "memory" problems with nicads seem to have been alleviated and
now you don't have to completely discharge them before recharging.
However, if you have nicads that are more than 4 or so years old, they
might still have the memory problem.

There hasn't been a measurable "memory" problem in NiCds for thirty years. You
*don't* want to over-charge them or run a pack down to zero. Either will
damage them very quickly. Some have called these problems "memory effect" but
it's far different and irreversible (unlike the true "memory effect").