warning recharging classic ni-cd battery packs

[Don Shepherd]

I have always recharged my HP-65 rechargeable battery packs overnight when the LED's start to flicker. The battery pack was due to expire after 3 years, which would be next month. I thought I would check on the recharge after a couple of hours and I am glad I did. The back of the 65 was very hot, and part of the battery cover had melted. I removed the pack and it was hot.

Fortunately, the calc still appears to be working fine.

I'm not going to use rechargeable cells anymore, just regular AAA's in a small case designed to hold them.

So beware of recharging ni-cd batteries if they are about to expire.