There have been questions before about how to connect a portable to the RV's battery
Not what the OP wants, but posting it to draw attention to the adapter for connecting the solar controller to the RV's 7-pin cord. (scroll down)It seems this adapter is also available with other portable kits these days. (not always the best way to do this if there is much voltage drop, but ok otherwise)
Some years ago when I first got solar, time2roll suggested using the 7-pin, and I tried it out with a DIY adapter using just two wires and it worked. (Limited by wire gauge vs length of course) So interesting to see "real ones" available now.
http://www.wegosolar.com/products.php?product=180W-Folding-Solar-Panel-Kit-
