It happened on the kitchen table, without props on. I wanted to drain both Wifi extender and Phantom batteries, so I left both on. After Wifi extender died without any power left, the motors stopped, And there was still 15% more in the Phantom battery. I turned them back on and after 2 seconds they stop again. Is this normal? How come you can not fly the bird without Wifi extender on? I dont remember reading about it in the manual..