I do not ground the panels for the Rv whether attached on the roof or whether they are on a contraption on the ground away from the RV on longer wires.
The solar controller is not grounded to the RV frame either. Some are plastic so can't be chassis grounded, others are metal and can be. But some are "positive grounded " controllers, which confuses things.
Doesn't matter if they are "positive grounded" controllers or not, just don't ground them to the RV frame, and everything works great.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.