I've got my bat pack equipped. I've held it and right clicked multiple times. I had a fully charged chainsaw and mining drill. They both used up their charge and then stopped working. My mining drill disappeared after this happened once, I built a new one, recharged it, and used it till it was almost gone. I didn't want to loose another one at this point!
My pack does show that it had a tiny bit of charge used up, but I don't know how that occurred. Any solutions?