Solar Panel Roof Mounting

[Schrimscher]

Recently took delivery of 2018 Greyhawk 26Y and want to mount a 2 Ft. x 4 Ft. 100 watt solar panel on the roof. Hate to put holes in the fiberglass roof and considering 3M VHB (Very High Bond) double back cushioned adhesive tape. Screws and Dicor seems to be the usual method of attachment. Saw a couple U-Tube presentations using it and 3M has a great PR demo on it.
Anyone used the 3M method?
Paul

[MontanaBBQ]

If your fiberglass roof is like my 2016 Greyhawk, it has a pebbled texture. Additionally the thin fiberglass skin is not securely glued to the plywood underlayment. I recently installed some panels from AM Solar. They didn’t recommend the VHB tape on anything other than a smooth surface. I chose to use a combination of stainless screws, VHB tape and Dicor sealant on each mount. This is my third rv using this method.

Here is some DIY info from their website:

https://amsolar.com/diy-rv-solar-instructions/edmounts/

I’ve also read of people using some sort of expandable drywall type anchors, rubber well nuts, etc so there are certainly multiple ways to do it.

Good luck. -Doug

[kblast523]

Rather than poke a hole in the roof, I ALWAYS run power from the panels down through the fridge vent. In the two Jayco's and other off brand I've put solar on, the fridge was right next to the power converter. If you have to go through the roof, Wineguard makes a cable entry plate (P/N CE-2000) that will well cover and protect the cable and opening you have to make. The closer to the converter you get (AND do NOT forget the charge controller) the better the system will work. I generally go 200w on solar and add a house battery.

[Lathrop Bob]

My Melbourne came with solar pass through jacks. I got 120 watt flexible panels and attached them with that marine grade silicone adhesive. They work great and are so thin they aren't noticeable. My son did the same with his Melbourne. 480 watts is a good amount for small motor homes.

[MontanaBBQ]

https://www.jaycoowners.com/forums/f...els-53768.html

Add'l info in this thread

[Schrimscher]

Thanks Doug for your feedback and excellent link to Solar's website....great info. I noted that one of the videos did use 3M VHB with good results. My 100 watt Renolgy panel kit arrived yesterday and I has 3M 4950 VHB ordered. You have a great approach to mounting with 3M tape and fastermers which I think that's the way to go. Will check the texture of my roof and give Jayco a call to see how much glue they use when they put the fiberglass sheet on and their roof truss spacing to try and pick up a truss/rafter to attach to. Hope to get this done in the next couple weeks as weather and energy determine.
Thanks to everyone for your info. I'll keep you posted on the project.
Paul

[Schrimscher]

Finally got around to finish mounting the 100w solar panel on my 2018 Greyhawk 26Y. Found the roof was a pebbled texture like Montanna BBQ said so I used a combination of 3M tape ss screws and Dicor. Hated to drill the roof but didn;t trust only 3M tape on the pebbled texture over time. System is working good and glad I'm off the roof.
Paul

[ekdave]

Originally Posted by Schrimscher

Finally got around to finish mounting the 100w solar panel on my 2018 Greyhawk 26Y. Found the roof was a pebbled texture like Montanna BBQ said so I used a combination of 3M tape ss screws and Dicor. Hated to drill the roof but didn;t trust only 3M tape on the pebbled texture over time. System is working good and glad I'm off the roof.
Paul

Paul, what size screws did you use? My Renogy z-mounts came with what look like self-drilling wood screws about an inch long.

Dave

[Schrimscher]

Dave
I found some self-tapping 1 inch # 12 screws with a rubber washer under the head at Home Depot. There were some other choices, but went with this one. The ones from Renogy had a finer thread. The panel wire connectors matched up to the pre-wired plug-in on the roof, but limited the placement to between the vents, so I wasn't able to screw into the trusses. With the 3M tape, grommeted screws and plenty of Dicor it should stay in place with no leaks. Will check the Dicor each fall before our winter rains.
Paul

[JesseS]

Originally Posted by Schrimscher

Hated to drill the roof but didn;t trust only 3M tape on the pebbled texture over time. System is working good and glad I'm off the roof.
Paul

I will not drill into my fiberglass roof, so I used Marine 5200 vulcanizing adhesive to mount 'L' brackets to the roof for my 4 200 watt panels. Almost 3 years and still strong as ever. I had previously used the same adhesive on my last coach and after 7 years the brackets still had to be removed with a wire saw. This adhesive will cure under water, and has the feel of car tire rubber when cured, it is meant for hull pass-thru or deck adhesive on boats but works great for your RV.
*CAUTION* Once applied and cured this adhesive can NOT be removed without a LOT of work.