Adding Solar Panels to a 2026 Navion 24R Roof

[HRYSER]

I consider adding more solar panels to the roof of the 2026 Navion 24R.

Should I use soft panels glued to the fiberglass roof? Any heat concerns?

Or should I use hard-framed panels screwed to the fiberglass roof? Any concerns running screws into the roof?

Looking forward to hearing back from you.

 

[creativepart]

The factory panels are Xantrex brand flat panels and stuck to the roof. I believe they are “peel and stick” but not positive. And if you purchase the Generator Delete option the two additional panels are also flat panels. So, the factory must prefer this route. Also, weight is very much an issue with rigid panels and their mounts.

Personally I would stick with flat panel if I was adding solar panels to my roof.

(And… fiberglass roof? That not really an accurate description of your roof’s construction.)

 

[HRYSER]

Hi Creativeparts. Thanks again for your analysis and hints. I truly appreciate your very helpful responses you provide to this Winnebago crowd.

Just to make sure I understand you right, by "flat panels", you referring to the flexible, glued-on solar panels. Is that correct?

My apology for misnaming the roof's material. May I ask you what material the roof is made of?

Thanks again and best regards

 

[creativepart]

Yes, by flat panels I mean flexible non-rigid panels without frames.

Your roof uses a sandwich design with thin interior Luan paneling, on top of a thick layer of high-density polystyrene block foam, with an external layer of a seamless exterior FRP skin. That's a thin flexible solid plastic sheet that has had fiberglass strands mixed into the plastic during manufacturing. While it's strong in the lateral dimension it is weak in sheer strength. Making it easy to tear.

All of these pieces glued together make a for stronger whole than any of the parts individually. The key to making this work is proper gluing and no water intrusion, which as you can imagine isn't always the case. There are no roof trusses under the structure, it's gets its strength only from the layered construction. This is why Winnebago strongly advises twice a year roof inspections.

There are RVs with real fiberglass roofs but that's different, it's a gel-coat solid fiberglass structure like a Corvette or a boat. And, according to Winnebago's promo dept the new $300.000 Arka expedition RV has a solid fiberglass roof.

 

[HRYSER]

Thank you kindly for the detailed information. The construction is amazingly complex!

I have read in an other post that these flat panels can reach a temperature of about 160F in full sunshine. Isn't this heat exposure damaging to the complex roof composition?

Would you know by chance what adhesive Winnebago used to install these panels?

 

[creativepart]

Thank you kindly for the detailed information. The construction is amazingly complex!

I have read in an other post that these flat panels can reach a temperature of about 160F in full sunshine. Isn't this heat exposure damaging to the complex roof composition?

Would you know by chance what adhesive Winnebago used to install these panels?

One has to assume this is not an issue for the roof or they would not been doing this for all these namey years. And, as for adhesive? I read on the Xantrex website that the panels are peel and stick. I have no idea if that is all that's used.

 

[HRYSER]

Thank you again for your input. I assume Xantrex would provide some input to this question.

 

[Gkiesel]

Keep researching this issue. Some folks on the view/navion fb page have had damage to the filon roof from flexible panels. They claim the lack of air circulation under the panels leads to delamination of the roof. Hence they recommend rigid panels with an air gap underneath.

 

[fanrgs]

The factory flexible panels on our 2020 Navion are screwed to the roof, then the screws are covered with a thick layer of self-leveling sealant. I was concerned about holes in the filon too, so used 3M marine adhesive to add two more panels. A year or so later, one of those panels blew off the roof in Texas when hit by a very strong tail wind. So, I bit the bullet when I replaced that panel by screwing both of my added panels to the roof, then covered the holes/screws with Dicor-like sealant.

I haven't seen any heat roof damage from the flex panels in the 5 years we have had the 24V. And, with the low CCC that all the Sprinter Class C's have, the weight of framed glass panels would reduce it even further. You would be replacing 10lb. 200w panels, with 25lb. 200w panels. But, if you don't already have them, some of that added weight could be offset by replacing the 75lb. AGM house batteries with 35lb. LiFePO4 batteries.

 

[SoxFan]

2027T with generator and 2 panels from the factory. While the generator replacement has 4 panels, 3 across and 1 centered to the rear of the 3. When you get 2 panels they seem to center them. That allows adding the 1 to the rear the other 2 are centered so there isn’t room to add the other so it has to go forward to the driver side. This isn’t the best location as a low sun angle leaves the panel in the shade of the AC.

This was done by Winnebago.

It’s crazy that they don’t offer the 4 panels as a separate option.