We have a small 2014 15ft Trillium fiberglass camping trailer. Many time we will camp without an electrical hook up. is there snything wrong with just backing up close enough or even getting an 7point extention cable and plugging in my car to the trailer. Not hooling the trailer to the ball. And then letting the car run until I get 4 lights lit uo pn my charge indicator in the trailer. Would it charge better if I connected the ball to the hitch?