According to CycleDog, many house fires are attributed to battery charging systems. He's seen a cordless phone fly across the room when its battery blew, and a water-bottle battery burn up its charger. He writes, "Please be extremely careful when handling leaky batteries! Be wary when a battery seems to be getting warmer than usual while it charges. Your eyes, your skin, and your family are worth far more than a battery or a charger."