Originally Posted by ItsJustMe
Heat is OK in moderation. Good smart chargers actually have a heat sensor to regulate this. My AA charger in fast mode will send NiMH AAs up to about 130*F; pretty warm but not really hot.
My NiMH battery pack has some kind of thermocell or something inline with the batteries. I think the packs at battteryspace.com have it too.
I use a smart charger from batteryspace.com after I fried my old one.