Do the eGo batteries give any warning or do they just die out of the blue one day? I've had mine for 2 months+ and it didn't charge overnight like it always has. It charged while I was awake no prob, so I don't know if I should express mail a new one right now or risk it. It's my only 510 batt, and it's an eGo-C upgrade passthrough, 650 mAh.