You can do it one of two ways. You can install a deep cycle battery on the trailer and hook up the reel to it. Or you can run a pair of wires the length of your truck from the trucks battery and hook it up that way. I've done it both ways. Make sure that the wires at least 10 ga or better yet 8 ga. Have a plug at the rear of your truck so you can unhook the power wires when you drop the trailer.