I have a 24V Panasonic rotary hammer drill, model EY6813. It came with two 3.0 amp-hr NiMh batteries, both of which had a problem with one of the contacts almost welding itself to the contact in the drill, and also in the charger. I stopped using those batteries. Now, using an external 7.0 amp-hr NiCd, it's worked fine until recently. The drill began to intermittently shut-off, then quit working altogether. I then noticed that the battery, the wire running to the drill, and the contacts in the drill were hot (battery was very warm, the wires & contacts were VERY hot). Any ideas about the problems with the NiMh or NiCd? Could it be the drill and not the batteries? The hot batteries/wires occurred after minimal runtime, so I don't think its a matter of overdrawing the battery, but I'm just not sure. The vent holes on the drill are not blocked.