Help! I have the Phantom 2 Vision, 5200 battery and stock charger. I have only charged it once. The phone tells me that I have 86% battery left. I wanted to fully charge it for an upcoming trip, but when I plug the battery into the charger, non of the lights on the battery come on. The light on the charger does, but not the battery. Is this normal? Does it have to get down to a certain level before I can recharge?