Roof is pre wired with 8awg wire, to the basement area behind where the vacuum cleaner is mounted. To install solar PROPERLY, you will want to get your controller much closer to your battery bank. I extended the factory controller wires to the recessed area of the basement, drivers side, directly behind the wall from the battery box, then ran much heavier wire through the wall, to the batteries.
The advantage of off-grid solar is capturing power for use when you need it, vs just having it available when the sun is shining brightly. For that, you will need more than just the single factory battery.
Be Safe, and Everyone Goes a Home,
2014 RAM Laramie 2500 w/6.7L Cummins Diesel and Automated Safety Hitch
2016 377RLBH Jayco North Point
300W of Suntech Solar w/Rogue MPPT Controller & Xantrex 2000W PSW Inverter