Just thought you would like to know - I tried the battery charger on another battery - outside in a metal bucket. It worked just fine. Battery came up to full charge and the charger switched modes to "maintain" and signaled the tone that indicates the charge complete. I now believe the exploded NiMH battery was defective to start with. I will still continue to charge my batteries outside or in the garage (away from flamables) and in a metal container. Am I overly cautious? Perhaps, but having had this happen makes one think twice about things.