Battery charging and heat

[Skwerly]

How hot is the charger/battery pack supposed to get? i charged one battery pack and it didn't get mildly warm. i charged the second and i could barely touch the charger.

is that normal?

 

[Rolex]

We need to know what type of batteries, what mAH, what type of charger, is it air cooled, how close back to back did you charge, and at what rate.

 

[Skwerly]

the batteries were charged several hours apart. lemme get the specs, i didn't think of that.

first battery pack: 3300 six cell NIMH by "venom power"

second: 4500 NIMH six cell by "Hi-Energy"

Charger: vision peak2 run on wall current at 4 amps, both batteries. i have the choice between 1, 2 or 4 amps and since it defaulted at the 4 i just used that. have since switched it to 1 amp but haven't had to charge again.

if ya need more info i'll give hehe. i just don't really get why the second pack got so hot.

OH something occurred to me: i did NOT unplug the charger to reset it after the first pack... maybe i should have?

 

[Rolex]

I don't know if the reset would have made a difference. You might be having a problem with that battery.
Next time you charge, do it at the lowest setting. It will take longer, but you can monitor the results if it starts to overheat.
Some batteries get hotter than others during the charge cycle, Turnigy, for example, but that shouldn't over heat the charger.

 

[Skwerly]

okay thanks. i read the instructions for the charger and it said to "allow charger to cool between uses" so i assumed that meant it could get a bit warm, but this mutha was really hot haha.

 

[Rolex]

I guess that's it. Just don't charge big batts back to back.

 

[Metalhead Matt]

4 amps is too much for a 3300mah battery. 4000mah bat = 4 amps. 2500mah bat = 2.5 amps. 5000mah bat = 5 amps, ect... These are the highest rates you theoretically can charge at. Not all batteries are created equal, which means that some 3000 packs can deliver and receive more current than some 4000 packs, and so on. I'd do exactly what Rolex said to do, then charge at the 2 amp setting once you're confident that everything is ok. This will give you a little more pack life as well. I always run a fan on my chargers and batteries. But a fan can give you a false sense of security when it comes to battery temperature. I only use a fan on the batteries after I let them charge naturally and determine that the peak temp is within safe range(125 degrees).

 

[Skwerly]

ah! i did not know that. thanks man! that makes total sense. two amps seems like a great compromise, because the 1 amp seems to take forever haha. thanks!

 

[Metalhead Matt]

1 amp is no fun. Only for rx packs. Example: I got a lot of my rc equipment ripped off last year. All I was left to charge my 4200 Tenergy's with was a Traxxas power pack charger. 1 amp output, automatic 1 1/2 hour shut off. I had to start charging batteries at 5 A.M. to run at noon. And you know I forgot about that damn shut off feature way more than once.

 

[MotoGod]

4 amps is too much for a 3300mah battery. 4000mah bat = 4 amps. 2500mah bat = 2.5 amps. 5000mah bat = 5 amps, ect... These are the highest rates you theoretically can charge at. Not all batteries are created equal, which means that some 3000 packs can deliver and receive more current than some 4000 packs, and so on. I'd do exactly what Rolex said to do, then charge at the 2 amp setting once you're confident that everything is ok. This will give you a little more pack life as well. I always run a fan on my chargers and batteries. But a fan can give you a false sense of security when it comes to battery temperature. I only use a fan on the batteries after I let them charge naturally and determine that the peak temp is within safe range(125 degrees).

I wouldn't say 4 amps is too much for a 3300mah battery. The good rule of thumb is 1A per 1000mah so 3300mah would be 3.3A charge rate...but you should be able to safely charge a 3300mah all the way up to probably 4-5A without any damage. You just need to monitor it. Batteries tend to get warm/hot at the end of a charge/discharge cycle. The type of cells and who made them is really the factor here...some just get hotter than others.

I'm no electric expert, but I've managed to keep my packs alive awhile thus far....so if you are unsure what to do....just charge at a low A rating and wait longer ;-)

 

[Skwerly]

Excellent, thanks all! Oddly, the 3300 pack is the one that never gets even warm haha, it's the bigger pack! I'll check the connections and at least try it at the 2 amp for longer. Seems like the ticket.

 

[MR4X4KING]

when i bought my summit it came with 7 cell 3300 mah batteries and they tell you to charge them at 4 amps peak charger

 

[Metalhead Matt]

I've seen 4500mah bats on ebay that call for a 1.5 amp charge rate. You have to use better judgment when it comes to batteries. Mainly, watch the temps. You can charge 3000mah bats at 5 amps. But you better take em off the charger when they get warm, let em cool, and put them back on the charger until they're warm again, ect... Don't count on the charger to keep you and your batteries safe.