Community Forums

RVGlen · 10-23-2019, 11:30 AM

I'm planning on installing residential solar panels on my fiberglass roof and was going to use the 3M double sided tape to hold the brackets down. This is all new to me. I see some people using unistrut and found an advertisement for rocker feet brackets from AM Solar.

What's the best method to mount residential panels on a fiberglass roof? (hardware, tape or screws, etc.)

I'm looking at putting two across the back, side by side, and one in the front on the door side. I then may put a couple of smaller panels on the door side beside the A/Cs. I do not intend on tilting the panels.

vito.a · 10-23-2019, 03:07 PM

I used these aluminum mounting brackets with 3M VHB tape. On larger panels I'd recommend 6 brackets per panel.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I used this 3M 5952 VHB tape. Be careful, there are some non genuine VHB clones out there.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

In the end, I added two screws per bracket into the fiberglass roof and sealed the bracket edges and the top of each screw with Dicor.

You should also look at brackets from AM Solar. They are more expensive but excellent quality.
https://amsolar.com/rv-solar-panel-k...ng-accessories

RVGlen · 10-24-2019, 04:25 PM

So you wouldn't recommend using the unistruts?

vito.a · 10-24-2019, 10:32 PM

I'm not an expert. I spend some time researching and am now installing my own system.
I calculated the watts per square inch from various panels. The LG and Panasonic panels are generally recognized as the highest output panels, but I found 200W +25% bifacial panels had the same output per square inch and more if you get additional output from the bifacial aspect. And they are much easier to fit around obstacles than the larger commercial panels.
https://www.ebay.com/itm/200-25-Watt...72.m2749.l2649

Unistruts may work, but you will need to work around A/C units, roof vents, TV antennas and what ever else is on your roof. Additionally the roof on most 5th wheel trailers is raised up over the front area.
I'd cut out a piece of cardboard the size of the panels you intend using and get on the roof and get a feel for your layout.

RVGlen · 10-25-2019, 11:42 AM

Thank you!

I may not be able to put a residential panel on the front section of the roof. I know I can put two on the back. I had looked at bifacial though I was reading they needed to be mounted roughly four inches above the roof. I wasn't seeing any mounts that would raise it that high.

I was also thrown when I read about the 3M VHB tape saying, "Recommended to use 4 square inches of 5952 VHB tape for every 1 pound of load". So that lead me to think the unistrut bracket may be better. I don't know.

I can see me driving down the road with a panel flying off or a section of my roof with a panel flying off. I don't want to put holes in my roof on purpose.

Monaco Wolfy · 10-27-2019, 10:34 AM

Make your own brackets with 2 inch aluminum L metal. Home Depot has it. If done correctly it will put your panels surface 4" above the roof surface. Depending on how long you cut your lengths of metal, you can add as much tape as you want to hold them to the roof.