The "memory effect" is mostly a myth for NiCds. What happens is that the
voltage is depressed
for much of the discharge curve, but the amp-hour capacity is not affected. But
many devices
assume a higher voltage, and the depressed voltage is not enough for them.
Also, NiMh may have higher capacity than NiCd, but NiCd can discharge faster.
NiCd supports
faster recycle times.
But NiCd has cadmium, a poisonous heavy metal, so switching is good for the
environment.
tOM
On Saturday, August 26, 2006 at 14:22,
Chuck Norcutt <olympus@xxxxxxxxxx> wrote:
> It could be that the NiMH are old and tired but it may also be that you
> don't understand the oddities of NiMH batteries. While they pack a lot
> more power than an alkaline or NiCad cell they also have a very high
> self-discharge rate. Just sitting on the shelf doing nothing they lose
> about 3% of their charge *per day*. Let them sit around for a week or
> two and they begin to look like weaklings.
>
> If it's been more than a few days since you've used them it's always a
> good idea to top them up. Topping up was a no-no for NiCad cells
> because of their "memory effect" but is a necessity for NiMH.
>
> The memory effect on NiCad cells is that if you only drain them to, say,
> half power then they come to "remember" that half power setting as the
> zero power setting. The more frequently you top them up the less
> capacity you get from them. Resolving the problem requires multiple
> full dicharge cycles to reset the "memory". NiMH do not suffer from
> this problem but they're happy to use up the power all by themselves.
>
> Chuck Norcutt
>
>
> Candace Lemarr wrote:
>
> > The thing is...the NiMH battery is not giving me much life at
> > all...perhaps they are tired and I need new ones.
-- Quidquid latine dictum sit altum viditur --
,__@ tOM Trottier
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</ </ This world, after all our science and sciences, is still
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