Hi, I have a phantom 4, my rc controller used to charge my devices ( iphone and ipad) when connected and flying and now it has stopped doing that. I can still connect to the DJI GO APP but I am worried that I have a defective USB PORT. Once I connect my Iphone to the controller via usb port it says charging for a split second, then no longer charges. Has anyone had any problems like this? Any suggestions? Should I be worried or does the USB port on the controller not suppose to charge thed evice when connected.