Good charging settings?

[ohmygahitscoby]

Hey everyone, I've been charging my NiMH packs and they've unusually have gotten hot while charging. I discharged them with my Tamiya NiCD Discharger (I don't think there is a problem using the NiCD discharger on NiMH packs =/) then I plug them in, and after a while they get hot. These are my settings:
3.0A Charging rate
Delta Peak 8mV/C
Trickle 100mA

Should I fix anything? It's a Piranha charger BTW. The packs get to around 140F.

 

[abadk9420]

Thats getting a little hot, are you letting your batteries cool down after you discharge them? you want your packs to be cooled down before you recharge them, how many mah are your batteries that your charging @ 3 amps?

 

[ohmygahitscoby]

They don't get hot when I'm discharging them, should they? Anyways, I'm charging a 4500 MaH and a 3800 MaH.

 

[abadk9420]

They don't get hot when I'm discharging them, should they? Anyways, I'm charging a 4500 MaH and a 3800 MaH.

It depends on how fast they are discharging, if they are discharging slowly then know they won't get hot, but if you discharge them quickly then they will tend to get hot, at any rate charging batteries of those mah at 3 amp should be fine, but you could try the next setting down and see if you get the same results, also you may want to watch the batteries closely when they are getting close to peaking and when you see the voltage start to drop pull them off the charger it could be that the charger is not turning off soon enough causing the batteries to get 140 degrees. you might also try lowering your delta peak so the charger will cut off sooner but the only problem with that is when you first start charging the battery it may false peak because some time when you first start charging the batteries the voltage drops a little before it starts going up.

 

[ohmygahitscoby]

What's weird is that I just charged the 4500MaH and it wasn't as hot. It used to get hot when it was only half-way charged, now it charged normally. I'm charging the other one (Of course, after the charger cooled down) to see how it does. So far it's half-way and it's doing fine.

 

[HeartBreak]

Typically, I set my Delta-peak to as low as the charger will go. My Novak Millenium will go to 4mV/C, and I've never had a pack get above room temperature.

 

[ohmygahitscoby]

alright, I'll try that. Thanks!