Energizer 15 minute NIMH Charger Report

This may screw-up the fast-charge algorithm, which was undoubtedly designed with only the existing fan. (It is impressive that it has a built-in fan!)

Thus the reason for the fan, to cool your fingers :-).

If you do manage to dissect/figure out the charge algorithm, it'd be interesting. The "consumer" battery companies have always been half-assed about telling us techies things like battery charge rates, capacities, etc. Obviously they don't want to turn market differentiation into a simple single number, when they can have a rabbit banging a drum instead!

Tim.

Mine didn't get anywhere near that hot. They got warm, but not uncomfortably so. You didn't put on cells that were already charged, did you? That can confuse the charger and the the cells hot. I've seen it described before.

Does this site contain the info you're after?

Dave

It seems that advertisers don't want to provide ANY kind of usable information about their products. Most advertising is all about sizzle, and not a word about the steak.

I am pretty sure the fast charge will shorten the total use life by some degree. Just how much seems to lack exploration. However, given the low cost of NIMH batteries, the convenience will probably outweigh the shorter use life. If a set of NIMH batteries (4) costs $12, and slow charged can be recharged 500 times, and will take 150 pictures/charge, the cost per picture is $0.0016 per picture. If fast charging reduces this to only 200 charges, then the cost rises to $.004 per picture. It seems worth the money to me to have the extra speed. Those for whom the extra .24 cents/picture is excessive, can stick with the slower charger.

As I understand the mechanism, recharging from empty will probably not result in a higher maximum temp. Recharging from almost full will result in higher temps, however.

I concur 45c is on most Nimh data sheets. And can feel hot to some people.

Also fast charging , only charges the cell to 90-95% of capacity. So it sounds like the charger is working as designed.

Cheers

In article , Martin Riddle wrote in part:

I suspect somehow that somewhat hotter is not too bad if done for only

I have the Ray-O-Vac 15 minute charger and "IC3" cells that came with it and more of these same "IC3" cells. They get definitely hotter than 45 C. I just topped off a few cells just so that I coyuld read them with my recently-acquired "Raytek" remote thermometer, and got 58 C as a high reading in an ambient of 27 C. I expect that full charge from "empty" will heat up the cells a little more than this.

- Don Klipstein ( snipped-for-privacy@misty.com)

Did you read the site Ron? It's got all the technical specifications I've ever needed. Granted, this info isn't in their advertisements or on the consumer area of their website, but it is readily available.

Duracell NiMH:

Dave

Assessment of *hot* is very subjective indeed.

like the charger is working as designed.

Yup.

Graham

I'd be leery of any NiMH charger that got cells that hot. 45C is considered by most to be the upper terminating temp, at which temp you can certainlytouch them.

A fast charge unit that pumps that sort of current into cells should only be used with cells designed for high rates.

I suspect that the design trades cell cyle life for the "convenience" of superfast charging.

I was trying to illustrate that it probably doesn't matter unless one is REALLY strapped for cash, in which case buying a digital camera probably wasn't a good idea. In the one case, 10,000 pictures would cost 16 cents, in the other, 40 cents. Not many people would consider this significant.

The issue wasn't website information, but advertising, which often includes NOTHING of substance about the product (some ads don't even SHOW, or mention, their product!), just the company name.

I gave up on the quality of advertising somewhere as a child, when I realized toys weren't as big as the ads made them appear.

I focus my complaining on more influenceable things like traffic :o)

Dave

Paul,

the charger should recognize that and stop charging in time.

If not, it would have to carry a warning not to insert fully charged batteries.

Hans-Georg

Ron,

add to this that you may need fewer batteries, because you may only need one set for one device, rather than two (or two, rather than three).

In your theory, you would then have to discard them more often and replace them with new ones, but your 500/200 figures are purely speculative. We don't even know whether ultra-quick charging reduces the endurance of the cells at all.

Hans-Georg

Dave,

very good site, thanks!

Hans-Georg

Ron,

yes, I understand. It's one of those flat optimum decisions where it doesn't matter much how you decide.

Hans-Georg