My understanding on this issue is the pre-wired set up is inadequate for a really efficient solar panel set up and that heavier gauge wire must be pulled regardless of the factory set up. But, i am certain someone with expertise will confirm this and offer some thoughts about how to get a solar power source which meets your needs.
Happy trails and Good Luck
Ms Tommie Fantine Lauer, Greensboro, NC
AIR #31871 WBCCI #4165 K4MTL