Solar panel install on motorhome roof

[Belle]

We are looking to install a small solar panel (+/- 20” x 30”) on the top of our 78 Argosy MH. Figured I'd post here since the topic also applies to Classics. For integrity reasons, we are not interested in any drilling in to the shell. This leaves the AC cover or the rear roof vent cover as attachment points. The current preference is the vent cover as this will provide some air deflection at freeway speeds. Has anyone made a similar install to the roof vent (or AC cover)?

[tevake]

Lester and others here have talked about using adhesives to attach panels to the roof successfully.
I'm not sure of the type, you could PM him, or stand by the details should show up soon.

Cheers Richard

[WayneG]

Check out my install on a 84 Excella 270
http://theouterlimits.ws/projects/airstream/solar/

[Boom Sounds]

I used a Baird panel stuck down with Sikaflex. Runs through fridge vent down inside of cavity (through trunking secured to wall) and then through grommets to the solar regulator. I don't think this interferes in any way with the rear of the fridge but wanted the leads secure and not flapping about. The edge of the top fridge vent is sharp, so I slotted the + and - leads through a small piece of garden hose to protect them at this point. This is invisible from ground level.


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[Belle]

Boom_Sounds: Where on the roof did you mount it?

[tevake]

Sorry I meant to type Lewster earlier.
An exceptional adhesive that I do know of is 3M 5200.
Messy to work with, but great bonding and very durable.

I think that Lewster uses some sort of double sided tape adhesive.

Cheers Richard

[Boom Sounds]

Belle - front of panel is just behind the air con or about a foot behind the fridge vent


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[Boom Sounds]

I used sikaflex 521


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[Belle]

Originally Posted by tevake

Sorry I meant to type Lewster earlier.
An exceptional adhesive that I do know of is 3M 5200.
Messy to work with, but great bonding and very durable.

I think that Lewster uses some sort of double sided tape adhesive.

Cheers Richard

Thanks Richard - I new you meant Lewster.

[lewster]

You rang???

3M VHB tape #4950 with a SikaFlex-221 covering over the mounting feet. Have not lost a panel in 15 years with this method. Yes, 3M 5200 is a good bonding agent as well but requires far too long to cure for the type of work that I do. The SikaFlex is comparable in strength to the 5200 and as it is a moisture cure single component polyurethane, will cure in a few hours in normal humidity. Here in FL, it goes off within an hour and is fully cured in 12.

I only use this on metal or smooth fiberglass RV roofing. if you have a textured fiberglass, EPDM rubber or other roofing substrate you still need to use screws as well.

[Boom Sounds]

That's right, I used the 3M tape and the sikaflex.....poor memory. Good point on the rubber coating, didn't think about that


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[Belle]

Ok then, 3M VHB tape #4950 with a SikaFlex-221 covering it is! Thanks for the help.

[WayneG]

I know most everyone will disagree, but I used VHB tape and screws.
Of course my MH is a 84 and has lots of other defects, so I am not afraid to drill holes in it, if it suits my needs.

My reasoning is that my front 2 panels are right after the curve of the Motorhome roof where they will get a lot of lift forces. Even though the VHB tape is awesome stuff for holding at normal temperatures, the aluminum roof baking in the sun can get close to the upper limits where VHB starts to loose strength. (Strength depends on which version of VHB you are using, see this pdf chart from 3M. Don't use the cheap stuff!)
http://multimedia.3m.com/mws/media/9...alty-tapes.pdf
For whatever reason, I cant link to the PDF, so you will have to copy & paste the link in your browser.

Rocker mounts with VHB tape and stainless screws into the skin and rib.

Panel mounted where the front curve of the cab ends.

[Boom Sounds]

I've gone for the 3m tape and sikaflex. It's on a slightly defective rubber roof, so I will keep and eye on that. It's just behind the air com unit, so protected in some respects. The Baird panel is flexible so hugs the curve in the roof. I'm going to stick some more sikaflex on thee front edge to stop potential lifting and also keep an eye on it.


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[Boom Sounds]

I went for this, taped with the 3m and glued with sikaflex. Invisible and hugs the curves.


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[Gregsch]

I went with VHB tape and sealant from AM Solar. Worked great and no new holes drilled in the skin.

[tevake]

So far we have discussed taping down flexible panels and caulking the edges.
And installing rigid panels with brackets with screws.

Has anyone found a good method to mount rigid panels using the tape without screws.
Why not just go with the well fitting flexible panels, you may ask?

First is the superior output and longevity of the rigid panels.
Second the mounting that allows air circulation around the panel which helps keep it cooler for better output.

I bring these considerations up for discussion and comparison with the use of flexible vs rigid panels.
Thanks for any input.

Cheers Richard

[Boom Sounds]

Good questions Richard. My weedy 150w panel will be outdated in a few years and will fail at some point. Will I be able to remove it and install another one? Uncharted territory. It seems to me the rigid panels have some clear benefits, as do the flexible. I guess one of the deciding factors is appearance. Personally, I would prefer not to have a rigid panel, but it's all as matter of choice.


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[tevake]

Clearly the flush mounted flexible panels fit the nicest.

I went thru a similar process 20 years ago when placing panels on the new pilot house we added to Tevake while in New Zealand.
I'm wondering if the performance and temperature tolerence for the Flexible panels has changed in the mean time.

We ended up making teak mounting trim for each end of the rigid panels that fit the curved shape of the roof. Once mounted they all but disappeared.

The four panels we carried covered all household needs till two or three totally cloudy days came along.

One big difference is that we never parked Tevake in the shade.��

Zoom in to see the panels just behind the blondie.

Cheers Richard

[trumpetguy]

I mounted five Renogy Monocrystaline 100 Watt panels using the Lewster method for mounting. 3 M tape to mount the bracket foot to the trailer, then smother the foot with Sikaflex. Just try to pull one off the trailer...you will hurt yourself.

I like the rigid panels. I have a flex panel I bought for experimenting. The cells can cup out becoming a trap for dirt, which reduces production.


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