Also when wiring the harness for the output, I used only 1 of the primary wires for my laptop and the single secondary for my screen. 1 ground wire on each of the outputs. I guess the other primary is not needed in my case and can just be covered up on the end. I also have a question for the input harness. I see that there is 2 12V battery and 2 grounds. Should I tie in both pairs to a single wire on the battery for both positive and negative or just use 1 of each and cover up the others at the end?