super overheated batteries
 

well i left my radio charging and went out for dinner then went to the mall. when i came back, my radio was melting:gasp:, no kidding literaly it was melting. i forgot to unplug the wall charger, but it was supposed to stop charging:neutral:. well i got the batteies out and tested the voltage and they were all above 1.2v. my question is can they still be used again?

here's the damage
http://i279.photobucket.com/albums/k...ho501x/001.jpg
http://i279.photobucket.com/albums/k...ho501x/002.jpg
http://i279.photobucket.com/albums/k...ho501x/003.jpg
some of the heatshrink came off of the AA batts
http://i279.photobucket.com/albums/k...ho501x/004.jpg

1.2v per cell is nominal... My guess is that their is a bad cell or their is a short in your pack.

What loading current did you use?

Those run of the mill cells don't like 1C charge rate from my experience. They heat up too fast and/or false peak when doing so. It seems they like a slower charge, so I usually charge at around 0.5C for a couple hours and they seem to like that a lot better. Also, I set the delta peak as low as possible (3mv/cell) - they just aren't as robust as normal R/C NiMHs.

Not that it is recommended, but if you must charge unattended, use the temp probe and set the temp shutoff value for something like 100*F. That way, if they aren't peaking right (from a possible bad cell), the charger will still shut off before you get melted parts.