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Re: NiMh charging.

Subject: Re: NiMh charging.
From: Walter Knapp <>
Date: Sun, 10 Nov 2002 18:46:10 -0500
Stuart Fairbairn wrote:
> Walt there is a good graph of NiMH battery discharge at the MAHA website (
> Thomas Distributing) also on the next page is graph of Battery charge
> retention in storage.

There are a couple different ones lurking around in their site. I can't 
remember how I got to the various ones. They all look about the same.

I've found that the ones I have do slightly better than that curve. I 
expect the curve was done on one of the earlier generation batteries. 
One of the things they have been working on is extending the voltage 
curve. The result is that with the Portadisc by the time it drops off 
99% you are pretty much done.

I routinely recharge at the end of two months, if they have not been 
used by then. I find they retain charge much better than the rating. I 
normally will run the discharge cycle on the charger first as they still 
have most of a charge. Probably not necessary, at least with the NIMH. 
The Nicads I have left it is necessary. Though the Nicads drop charge 
much faster. I don't consider them good for more than a week.

Note if I'm about to go on one of my multi-day forays, I'll generally 
charge up everything that's over 2 weeks. It's not a big deal as I have 
chargers along and can charge everything faster than I use it off the 
Ranger's battery. I normally will charge each nights batteries the next 
day when traveling.

I worry over the specs when buying, after that I just pay attention to 
how the batteries do. Whatever it is I live with.

BTW, I keep the various sets of 4 AA's in small ziplock bags, the 9volt 
individually in the same size ziplock and have a slip of card stock in 
each bag with the last charge date on it. Otherwise I'd never know. Too 
many to just remember. I'm going to make some sets of 2 from the ones I 
just took from the Portadisc to run the MP2. Other than some maglights, 
it's all I have that uses them 2 at a time. They are giving away a 
little 2 AA holder I'll probably use for those as I got a bunch with the 
order.

Walt




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