krw wrote:

On Sun, 04 Jan 2009 18:50:49 -0500, Jamie
t wrote:

Allodoxaphobia wrote:

On Sun, 04 Jan 2009 14:22:09 -0500, Jamie wrote:

I have a fire storm B&D and Crapsman drills , I do use them
alot but I do not charge the packs when done. I just throw them
in a little frig I have in the shop.


So -- when you need to use a drill, its battery is both cold _AND_
discharged.

I wonder why no one else has ever come up with this Grand Idea?
I don't know, I do know that I learned that trick from my
grandmother. She used to store the dry cells in the frig..

In case anyone hasn't told you, NiCds and NHMs aren't dry cells. These
cells don't benefit from storing cold, but are damaged by high
temperatures. Your idea of draining them before storage is almost
right. NiCds and NMHs should be stored discharged, but there is no
need to discharge them; they'll do that themselves, just fine, and you
won't risk reverse charging a cell. Discharging multi-cell NiCds
damages more batteries than anything else. Over-charging is second.

I agree that many people are too keen on discharging their packs until every
last bit of charge has been removed, at which point one of the cells will
be reverse charged and damaged.

If you store them fully charged and let them self-discharge, the rate of
self-discharge is likely to be different between different cells in the
pack, meaning that after storage there will be a wide variation in the
state of charge between the different cells. Then if the pack is
subsequently fast-charged, one of the cells may get overcharged.

I would aim to get the pack nearly flat, but not so flat that any of the
cells is at any risk of being reverse charged, before storing the pack for
a long period.

Chris