Came back from flying yesterday and one of the batteries in the case was happily showing two bars steady and one blinking. Ok, figured I bumped it. But it wouldn't stop. Just sat there blinking. Pushed the button, nothing changed. Put it in the charger. No change. Finally, I stuck it in the Phantom (which promptly started up) and then shut it down. It has subsequently accepted a charge and seems to be well behaved. It never got warm. It physically looks fine and is actually my newest battery - about six weeks old with perhaps ten flights. Just throwing it out there. These things need constant adult supervision.