charging gp3300 NiMh battery - gets hot!

[rellentlessUK]

I have a GP3300 battery pack and a protech 3 amp delta peak charger.

The battery always gets very hot when charging! (almost too hot to hold if squeezed in palm of hand) Surely the charger is meant to detect when its charged and prevent this? If the battery gets hot i assume its overcharging?? Will i almost certainly have damaged it and if so to what extent?

Is this charger junk or just not the right one for this battery? Could the charger be faulty? Would charging the battery while not fully discharged make a difference in terms of the heat?

What mains charger would people recommend that doesn't cost a fortune?!

thanks

Mark

 

[Çh®i§tiªñ]

Can you adjust the charging rates and voltage ?

 

[rellentlessUK]

nope, rates are set

 

[Candyman]

NiMH batts usually stay pretty cool if you charge them properly. I have had a few experiences just like yours. Rushing a pack to the fridge quick to cool it down... In my experience, they're charging too fast. For 3300 mAH, I would think that 3A would be fine. That's what I would have predicted for a charge rate. It seems odd that they're getting that hot. But it's not good. You would probably be better off with an adjustable rate charger. Knock the rate to 2 or 2.5A and see if that's better. I use an MRC
Super Brain 959. It's rather cheap, but works well enough. That's just one of many possiblities. But there are a number of delta peak chargers that are now very affordable..

 

[FastEddy]

Candymans post is right on the money.
When charging, heat = lost power. When a battery is being charged properly, it should never get more than slightly warm to the touch. The slower you can charge it the better off you are.
-Ed

 

[Wardo]

Originally posted by Candyman
NiMH batts usually stay pretty cool if you charge them properly. I have had a few experiences just like yours. Rushing a pack to the fridge quick to cool it down... In my experience, they're charging too fast. For 3300 mAH, I would think that 3A would be fine. That's what I would have predicted for a charge rate. It seems odd that they're getting that hot. But it's not good. You would probably be better off with an adjustable rate charger. Knock the rate to 2 or 2.5A and see if that's better. I use an MRC
Super Brain 959. It's rather cheap, but works well enough. That's just one of many possiblities. But there are a number of delta peak chargers that are now very affordable..

I charge packs on a piece of aluminum with a fan mounted to it to push air across the packs. I also have this old Hotshot products battery heat sink I use and don't have much problem. Rushing them to the fridge might not be the best idea, condensation biulds in the cells doing that.

If this is charging at 3 amps, I'm thinking he's not charging too fast. I think the charger you are using is not cutting the charge off at a low enough voltage drop. If the charger drops the charge at .05-.08 voltage drop and you are only charging at 3amps, you will overcharge the pack. 3 amps isn't a hard enough charge to get the voltage up high enough for a .05-.08 drop and not do this.

I charge at 4 amps with a .03 drop cutoff. Charging at 3 amps would make my method have a .02-.03 drop cutoff.

Next time you charge, hook a volt meter to the pack also. Double check that you're charging at 3 amps and watch the voltage while charging and note when the pack starts to get some heat in it and what the voltage is doing. If it is getting warm and the voltage has dropped more then .03 remove it from your charger, your charger isn't correctly setup for charging NiMH packs.

 

[cox049]

Hi all:thumbup:

I just got a super brain 959. My charging needs are:
The 8 AA x cell pack for the TX (JR-XS3), I'm using 8 2000mAh nimh.

Also the RX pack is a 5 cell 2000mAh nimh.

What settings, rate or whatever do I have to use for each?

Thank you Very Much