Originally Posted by MarsMan
Nice choice... I stand corrected. My panel is 200W and not 250W. I forgot I wanted a 250 and could not find the real estate to install. I contatcted Coachmen and asked for the roof structure drawings for my 24J. I was able to use selftapping screws to hold down one edge of the panel. I also dicored the crap out of it. The other edge I used expanding screwed (used in drywall and again dicored the crap out of it. On the leading edge I placed a deflector (small plastic tube) to keep wind from flowing under the panel and causing some lift.30,000 miles and several days in high headwinds and higher speed, all is good. I ran the wire down thru the fridge vent and under my kitchen counter. Put a cut off switch in line between the panel and the controller. The controller was mounted near my step where my batteries are located. Ran heavy gauge wire to the batteries. Also installed Trik--L- Start to keep things charged on the Benz side when she is not in use or boon docking/parked for extended time. Check your Coach batteries monthly to make sure acid not cooking off. After 1 year of continous use, levels remain at the proper levels. PM me if you have other questions.... I may not be able to answer all. I have had extensive experience with my Prism and its "quirks"
Thank you for sharing your installation method – I think I will follow your plan.
Wind load variables are are major concern to me. Given the cube shape of these Class-C units, I suspect most of the air and turbulence is pushed over the top of the coach roof creating a small area of stable, but negative pressure on the roof. The idea of simply (only) gluing a panel directly to a (fabric) roof membrane without other mechanical attachment terrifies me. Such installation would stress the roof membrane to substrate adhesion, damage the membrane, and eventually come loose. I will also ask Coachmen for drawings. It is my understanding that the Prism roof is constructed with 3/8 inch plywood covered by a TPO membrane. If so, that would make installation much easier as wood screws and adhesive would probably secure the panels ... although rubber well-nuts might be better.
I am also a bit confused regarding the factory wiring relationship between the coach and chassis batteries. Do you know how these are connected together? It seems that since the vehicle alternator system also charges the coach batteries, that a solar charger connected to the coach batteries would also charge the chassis battery. Is there a disconnect-solenoid between them?