Hot AA Batteries when charging

[TomPierce]

If this is not the correct forum, please advise.

I just bought some Energizer NiMH 2500 mah AA batteries and charger - although the package says 'batteries will become warm when charging' I think these got too hot.

I measured the temp using a Radio Shack temp probe and found the temp to be 110 F (in context, 120 F is probably about as hot as you can stand to hold in your hand)

Does anyone know the acceptable temp range for charging these batteries? The Material Safety Data Sheet on the Energizer site does not contain any info, and I don't know where else to look. I'm concerned that I may have fried a brand new set of batteries or have a defective charger.

Thanks,

Tom

[Thenethiel]

Is it the 15 minutes charger, with the small fan built in? If so, I have the same one, and yes the batteries get quite hot, that's pretty much inescapable when you're shoving that much energy into something that fast, but I've used it quite a bit, incluiding with some older Rayovac 1700 MaH's, and have had no problems.

[fetching]

same here, my batteries get pretty hot too. no problems for past two years.

[Harry Settle]

The quick chargers shorten the life of your batteries, due to the heat. If you want them to last longer use standard chargers.

[RobbTC]

I have a fast/slow charger and always charge it slow and they still get hot to the touch. I'd imagine they'd be even hotter if it was done fast.

[gasrocks]

DPreview has a great article on battery chargers/charging. Thomas Distributing is your best source for chargers/batteries. Read what they say about what temperatures are ok. Yours doesn't sound bad at all.

[felix21685]

the slower the charge the better the battery can absorb it. but they cost like 20 bucks for 8 with a charger so i wouldnt worry about it

[MarkH]

Fast charging = hot batteries = shorter battery life

BUT

Who cares? Why does anyone let this bother them? If my batteries need to be replaced every 2 years then so what? Lets face it - cameras and lenses are expensive, but AA batteries are dirt cheap.

Personally I'd rather charge my batteries quickly and replace them every 2 years than charge them over 16 hours and have them last for 4 or 5 years. I've got much more expensive gear to care about than my AAs.

[Salleke]

Fast charging = hot batteries = shorter battery life

BUT

Who cares? Why does anyone let this bother them? If my batteries need to be replaced every 2 years then so what? Lets face it - cameras and lenses are expensive, but AA batteries are dirt cheap.

Personally I'd rather charge my batteries quickly and replace them every 2 years than charge them over 16 hours and have them last for 4 or 5 years. I've got much more expensive gear to care about than my AAs.

If you charge your batteries in a fast 15 minuts charger every time they won't last for two year. I wonder if they last for one year!
You are right when you say that charging over 16 hours is annoing but NI-Mh batteries can be charged in 2 hours and that is a reasonable time and will give you the longer 2 years life time for the batteries. Depending on your maximum charging and discharging cycles to of course.
One other point to consider is our life environment. Batteries are a big problem for the world we live in, and disposing of batteries is a very expensive task in all the country's in the world. Every little bits helps. And if everyone helps a liitle bit then we and our childrens can still make nice and beautyfull pictures now and in the future.

[mdude85]

Um, yes, this is kind of hot. First make sure your charger is set to accept NiMH batteries -- some have an option to switch between NiMH and Cadmium, and some just accept Cadmium.

I just use a standard charger for the energizer batteries. It seems to do a full charge in maybe 6 or 8 hours, and if you charge them before you go to bed, they're done by the time you wake up. I have no reason to care, then, how long charging takes, especially since many chargers can fit four batteries, which is enough to use your second set of charged ones for the entire time that it is taking for the first (dead) set to charge. Why do I need to have a 15-minute charger if I don't need to use the batteries once the charging is done?

[MOSS]

I'm using a slow charger now. It's really killing me sometime.

I would like to buy a new faster charger for my NiMH and NiCd batteries. Would you recommand some good chargers?

Or just tell me what charger r you using (fast)? Do you thing it is good?

Thanks a lot!

[TomPierce]

The whole problem is that I was using a slow charger and they were still getting hot.

Since I posted this, I did some research with a friend of mine who is into R/C aircraft, and I found 2 recommendations


1. The normal battery charge is c/10. So your 2500mah battery should be charged at 250 ma, and your 1800 mah at 180ma. Chargers are usually marked with the output ma.

2. The fancy (read: expensive) chargers usually have a temp cutoff sensor to prevent overcharging - the usual setting is 135F (!!!)

As far as the quick charge chargers - they should only be used with the batteries designed for quick charge (quick charge batteries have slightly different chemistry than 'normal' charge batteries.

TomPierce