Re: Canon S3 or S5....?

On Thu, 2 Aug 2007 13:17:56 -0400, Neil Harrington wrote:

Li-Ion batteries also, as you note, held their charge longer, but
that's no longer true. The low self-discharge Eneloop type NiMH
cells hold their charge even longer than Li-Ion batteries, up to two
years.

I've read of the Eneloop cells but have never used 'em. They're more
expensive, aren't they?

Slightly, depending on where they're bought. Get 'em from Radio
Shack and they're far more expensive than Eneloops. I think that
several people have reported getting 4 of them for slightly more
than $10, which is a fair price. Their capacities are also lower,
2,000 to 2,100mAh per cell. For those that use their cameras for
flash units heavily enough to need to recharge the batteries at
least every week or two, higher capacity NiMH batteries are a better
choice. But if they often go a month or more between charges, then
the usable capacity of 2,000mAh Eneloops can be higher than that of
2,700mAh batteries.


I haven't used any chargers *that* fast and would tend to be
suspicious of what they do to battery life. Faster charging = more
heat which tends to kill batteries. My Maha C401FS chargers
have a fast (nominally "2 hour") rate and a slow ("5 hour") rate.

Faster charging doesn't necessarily produce more heat. It will,
most things being equal, but most things usually aren't. Check your
batteries while they're being charged and you'll see that in most
smart chargers they don't really get very hot until the very end of
the charge cycle. The really fast chargers are designed to keep the
cells as cool as possible. My Energizer 30 minute charger keeps the
AA cells space far from each other and is designed for better air
flow. It probably also does a better job of conducting heat away
from the cells. Others use a fan to cool the batteries. FWIW, the
little Sony smart charger that I use most often takes many more
hours to charge batteries than my RayOVac 60 minute charger. But
the batteries in the more massive, better built RayOVac charger
don't get nearly as hot as those in the Sony. And when the cells
get hot at the end of the charge cycle, they probably bake longer in
slower chargers such as the Sony. This probably does shorten the
battery life somewhat, but it can't be by very much, since as I've
said, I tend to use the Sony more than all of the others combined,
and the batteries charged in it have been used for several years
with no signs of drastically reduced capacities.


Often two or three cells in a set will fully charge (as shown
by the indicator lights) in a short time while the remaining
one or two may take hours.

Just a guess, but I'd think that these aren't really new
batteries, and that what you're seeing may the effect of some of the
batteries having lost much more of their charge due to having higher
self-discharge rates. But it's hard to say without analyzing
individual batteries, since the ones that charge quickly may be the
better ones because they don't have high self discharge rates, but
the ones that take longer to charge may also be the better cells if
it's due to the quicker charging batteries having lost a lot of
their original capacities. As you've said that the highest capacity
batteries you have are 2,400mAh, it appears that they're all beyond
adolescence, and it may be time to replace them with younger
2,700mAh cells or with the newer Eneloop types, unless they no
longer get much use.

.

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