I want to do something like 400 watts solar, on the roof, 2000 watt inverter (maybe an all in one) and 200ah LiPo batteries. The camper has "pre-wired cables" in a wall rated for 30 amps. I would have to cut a hole to see what is there. The electric panel and converter are in another wall, but also near the back. The shore power is in the back. The battery in on a tray on the tongue, and I would like to put the new ones there. What if anything, should I use of the prewire? other advice?