On 8 Jul 2005 08:50:46 -0700, Andy wrote:
I was just looking through the Mar/Apr issue of Wood magazine, where
they did an article on myths of rechargable batteries. One thing they
said really confused me - they said that rechargable batteries should
NOT be discharged completely, and that you should recharge them as soon
as you feel your tool slowing down, because if a cell is totally
discharged it can switch polarity and ruin the whole battery (or
something like that).

True.

I'd always heard that with NiCad batteries, you
DO want to discharge them completely, so they don't develop a 'memory'
and accept less of a charge each cycle. Does anyone have a good
explanation for why one or the other is true, or firsthand experience
trying it both ways?

Well, it's not about incomplete discharge, it's about frequent discharge
to the same level of discharge.

Also, they said that NiMH batteries are really not superior, because
even though they can have larger amp-hour ratings, they don't last for
as many charge/discharge cycles. I'd also read elsewhere that NiMH
batteries don't develop a memory, which seems to me like it would make
them last longer.

Well, it depends.

Has anyone used both types side-by-side through the
whole life of a battery?

It depends on what you're using it for. A cellphone where you throw it
on the charger when it beeps, you probably want the nickel metal
hydride, because a NiCd will (if memory is real - cue debate on that
now) eventually consider anything below that point not to be there.

It's complicated. Basically, given a choice, I'll go with the Nickel
Metal Hydride, but often it's a case of "Here's what battery works with
this" and that's your choice.