At 12:16 PM 5/8/01 -0400, Olin Lathrop wrote:
> > I've built up a 12V stack of them that is theoretically 10 Amp-Hours.
> >
> > I find the voltage floating all over the place while these batteries are
> > charging, and I can't imagine finding the negative voltage slope after
> > watching the voltmeter wander up and down so much while charging with
>about
> > 2 amps.
>
>I think you are charging them with much to high current.  The fast charging
>current for NiMH batteries is usually about 1C, which is probably 1/2 amp
>for these batteries.  I also wouldn't charge them as a 12V stack.  Too many
>cells end up in series and variations between cells can cause problems since
>they are all getting the same current.
>
>By the way, I changed the topic to EE.  AD is not appropriate anymore.

4C is workable, if the cells are designed for it, and the charger is right.
But you're right, 1C is much safer, and without a controller, I'd be
nervous at that.

Also, I agree on the voltage limit. You don't see it discussed very often,
but notice how few applications use higher voltage NIMH or nicad stacks.


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