I'm traumatized about sticking a solar panel with adhesives. My boss asked me to install a pair of 100w on his Hymer. These were the only that would fit on his crowded roof. The only space available was in front next to the auto sat dish and had to be mounted side by side but in offset. He bought the panels and mounting hardware at a specialised dealer and they assured him that special adhesive they supplied was the way to go. I followed the instructions and degreased the fiberglass roof where the supports would go, 4 each corner and 2 on the sides. I sanded the fiberglass to remove the thin layer of sunburn, dirt and grime and stuck the panels on.
He went for a few trips but one day, while returning from a trip, he took the motorway. He was doing 120kph and heard a noise. Looking in the mirror he saw something. He stopped and had the panel hanging by the cables. Very lucky nobody was hurt except my pride, when he called me
. Had to buy a new panel, remove the other one's glued supports and use a more secure method. I used a piece of stainless sheet to make a base support. The front one was bent in a wedge shape to deflect the wind over the panels and the back just a strip. The original supports were screwed to the sheets with countersunk screws and lock nuts, these supports were then glued to the roof and someanchors and screws were added to be safe.
On my build I think I went over the top. Better safe than sorry