Battery HOT while charging. Normal?

[photoguy2]

Hi, all, just a quick question. I just bought a lot of 6 NI-MH aftermarket (IMAX_EXPERT) batteries for the Jedi. I am trying to charge them in a NTN8831A Tri-Chem charger.

I know that the charger works fine (At lest with Ni-CD Jedi and Saber batteries). The issue is that the NI-MH batteries are getting VERY hot. Right now I actually have a band-aid on my finger with some burn gel from one of the charging contacts on the back of the battery. That was when I decided to stop charging them and ask here ;-)

They ARE charging, Right now I am listening to county fire/EMS on a MT2000 with one I already charged, and they were almost DOA, so I know they are charging, it just seems a bit strange they are this hot.

Is it normal for NI-MH batteries to get this hot?

Thanks
Matt
KJ6PNN

 

[jpc3]

John Creel, ENG/SNG Tech @ WRCB-TV3

I think this charger was designed for Motorola or Equivalent batteries that are Ni-CAD or Ni-MH. I believe the charging strategy for Lithium Ion batteries is different than Ni-CAD or Ni-MH. Hot batteries are usually the result of them being charged too quickly.

 

[K5MPH]

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This is a nicad charger only maybe

 

[mmckenna]

Those chargers are a Tri-chemistry charger and work fine for Ni-MH batteries. I used to run about 300 MTS2000s and we had a bunch of those and used Ni-MH batteries without issue.

What I'd suspect is more likely the issue is the battery itself. Looking at that brand on e-Bay, the price is really low, about a quarter of what I was paying for Ni-MH batteries from Motorola and other manufacturers. Based on that, I'd be more suspect of the battery itself. Poor contact design, internal wiring, cells, etc could all result in heating. Prices that low suggest that they've gone cheap somewhere.

Some battery warmth is normal when they are charging, but physically burning yourself is a very bad sign.

 

[photoguy2]

The plot thickens ;-).

On a whim I just tried the batteries in a aftermarket(empire wireless I think) Jedi only rapid charger. No heat buildup. They charged in the same amount of time too.

My recollection is that the OEM charger is a impres charger. Maybe that circuitry is causing that batteries to heat up?

Oh well, at least I can charge them in that charger. We will see what happens when I put them on the act I6 conditioning charger I have in the mail.

Matt
KJ6PNN

 

[mmckenna]

That isn't an Impres charger. Even if it was, they are not Impres batteries, so it wouldn't figure into this.

The difference in the chargers may have to do with the rates at which they charge. In other words, the amount of current sent to the battery may vary depending on the model of charger. Not all batteries can handle being quick charged like the Motorola charger you have will. Your other charger might charge at a slower rate/less current, resulting in less heat build up.

Either way, sounds like you have a solution.