A couple of days ago hubs went to work, he had a battery and the arrow key on a chain in his pocket together, he had to change locks on a community mail box, pulled out the arrow key and it was HOT... he was like ...? Then touched the battery and it was SUPER HOT... pulled it out and it was leaking or something, he threw it in the snow bank to cool it off before it exploded. Moral of the story... don't put your battery in the same pocket with your keys as it WILL cause a current if metal touches both ends of the battery. Thankfully he wasn't hurt but he could have been. His response was that he was an idiot, he knows better!!