I didn't mount mine on the roof, but that might happen in the future. Just got into solar this last winter out at Quartzsite and only have 1 140w panel. When I get more panels they might go up on the roof. But IMO there's just to much loss flat on the roof for 1 panel, and due to physical problems I can't get up there to tilt them. So my answer, for now, was to build a mount and mount it on the rear of the TT. That allows me to tilt it to face the sun or disconnect the mount and use it as a stand on the ground. 1- 140w panel will charge my 4 gp24 batteries by around 1-2pm. That allows us to watch sat tv, or whatever, till we go to bed. I still run our EU3000si for 1-1.5 hrs at night before 10pm to top the batteries because I use a CPAP. For charging I use a PD9260 converter.