On Mon, 26 Nov 2007 17:40:39 -0800 (PST), Pokee wrote:
> I recently just bought some new Energizer Nimh rechargable batteries
> (2500 mAh) and I started charging them on the Nimh Panasonic BQ390
> charger that I already have. It's been about 4 hours and they still
> haven't fully charged (they should have by now - as my Panasonic
> batteries typically charge in about 3 hours - they are 1950 mAh). I
> started to get concerned, so I looked up this charger's specs, which
> state "for use only with Panasonic Nimh regchargable batteries".
> Ooops. They're not Panasonic. But I can't see that being too big of
> a problem.
It shouldn't be much of a problem, if any. If (as I assume) your
1,950 mAh batteries are several years old, they probably have much
less capacity than when they were new, and it wouldn't surprise me
if they now are equivalent to 1,500 mAh or less. If they are 1,500
and take 3 hours to charge, then they would have taken about 4 hours
to charge when they were at their peak capacity of 1,950 mAh. Your
new Energizer batteries would then need about 5 hours to fully
charge. If your Panasonic batteries actually now have less than
1,500 mAh of capacity, then 2,500 NiMH cells would require more than
5 hours to fully charge in the BQ390 charger. A simple way to tell
if the batteries are being fully charged is to feel them and note
the temperature when the charger shuts off. For most of the 4 or 5
hours that they're charging, they should only feel warm. When the
batteries approach full charge, they should get much hotter. If you
don't notice a significant increase in temperature during the last
15 minutes (approx.) of charging, then the charger is shutting down
prematurely. As it's already taking more than 4 hours, even if it
shuts down early, the batteries would probably be fairly close to
being fully charged anyway, so there wouldn't be a large benefit to
buying a newer charger, especially since batteries deteriorate with
age and use, so in a couple of months they'll probably have
capacities of 2,400 mAh or less.
It I had this case to consider, I'd get a newer charger only if I
had some of the newer 2,700 or 2,900 mAh NiMh cells, or if I had
some need for a faster charger. I actually have a several chargers.
One charges in as little as 30 minutes, but I typically use one of 3
other chargers, which take from 4 to about 8 hours to finish
charging.
> I also found out that this charger is good for up to 2450
> mAh batteries (these Energizers are 2500 mAh). Ooops again. Have I
> wrecked these rechargable batteries now? Do I need to go buy a new
> charger, or would this one likely charge them well without any issues?
Nope. No harm done, and as I said above, your old charger is
probably fine unless you'd like to get a faster charger. If you do
decide to get a new one, try to make sure that it's capable of
charging each cell individually. Some of the cheaper chargers only
charge NiMH cells in pairs, and while they'll probably work fine
initially, they won't do as good a job as the ones that charge each
cell individually if your batteries aren't new or if all of them
don't have about the same capacity. It's not too difficult to avoid
wrecking your batteries, and the main way is to charge them before
they go dead. Some cameras drain the batteries so slowly when
they're not used that batteries can safely remain in them for 6
months or longer. Other cameras can cause the batteries to go flat
with even as little as a month or two of non-use, and if that
happens, one or two of the NiMH cells in the camera will probably
suffer some damage, ranging from losing a small amount of capacity
to being unable to take a charge.
>> Stay informed about: Energizer E2 Rechargable Batteries for Camera 
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