Radically different sized RV solar. Plus solar projects.

Old & Slow wrote:
Still hung up with the wiring thing. Junction box has no +/- so guess the Mppt will take care of that?

Cheap controllers have no reverse polarity protection, it will go up in smoke if you mess up the wires. Do yourself a favor and get $3 multimeter from ebay, they are cr-p but they will tell the polarity. Hold the panel to the sun - aiming is not required, as long as it;s not facing the ground, meter tell where is +/-.