I'm a newbie with three successful flights under my belt. No hitches at all. Until tonight where I was just flying about 100 feet up basically in circles recording scenery. The status indicator lights suddenly started flashing a slow red. Then back to green a few times, then slow red again. I know slow red means low battery but the phantoms battery was at 73% and the radio was fully charged. Made me really nervous to see all that red in the sky and brought her down. It's making me nervous. Any advise?