Installing flexible solar panels to roof

[Markz]

I am interested in installing a pair or flexible solar panels to the roof of our Boler.

I am also concerned about providing ventalation under the panel and the panels blowing off while traveling.

I was thinking about installing the panels on ribs that run front to back, parallel to the roof lines.

The panels are made from polycarbonate and I was thinking about making ribs out of polycarbonate as well. Gluing the ribs between the flexible panels and the roof via high strength marine epoxy.

My thought was to raise the panel off the roof 1/2". My fear is that they would catch do air and break off on the highway.

Any thoughts?

[Jim Bennett]

If you are not taking advantage of the semi-flexible panel by adhering it to the roof, why not go with a rigid panel?

[Markz]

Originally Posted by Jim Bennett

If you are not taking advantage of the semi-flexible panel by adhering it to the roof, why not go with a rigid panel?

Two reasons. First, I own two flexible panels already. Second, I prefer the aesthetics of panels that follow the lines of the roof.

[Mikmay]

Use high bond VHB tape and caulk around the front and sides with lap sealant and you’ll be good for years,

[k corbin]

Originally Posted by Markz

I am interested in installing a pair or flexible solar panels to the roof of our Boler.

I am also concerned about providing ventalation under the panel and the panels blowing off while traveling.

I was thinking about installing the panels on ribs that run front to back, parallel to the roof lines.

The panels are made from polycarbonate and I was thinking about making ribs out of polycarbonate as well. Gluing the ribs between the flexible panels and the roof via high strength marine epoxy.

My thought was to raise the panel off the roof 1/2". My fear is that they would catch do air and break off on the highway.

Any thoughts?

Your concern that they will catch air and break off is an accurate projection of what is going to happen. Stress from ongoing flexing in the wind equals material fatigue over time.

[Jim Bennett]

Originally Posted by Markz

Two reasons. First, I own two flexible panels already. Second, I prefer the aesthetics of panels that follow the lines of the roof.

I used semi-flexible panels for aesthetics too. I am just not understanding the whole raising them thing.

I wanted my system to be as indiscreet as possible, and cannot be seen from the ground unless you are well behind the trailer as the roof slopes to the rear.

I used Eternabond tape to hold them down, and an inspection last week showed that all was as good as new after 1 1/2 years.

[Markz]

What brand panels are you using?

I wanted to try raising them slightly to add airflow for panel longevity and to help keep the camper cooler.

Sent from my SM-G930V using Fiberglass RV mobile app

[Jim Bennett]

Originally Posted by Markz

What brand panels are you using?

I wanted to try raising them slightly to add airflow for panel longevity and to help keep the camper cooler.

Sent from my SM-G930V using Fiberglass RV mobile app

I am using Lensun panels. Really tough, you can walk on them. No have seen no reason to raise them, the heat has yet to be a problem even using them in Arizona, though this was in February. I can't possibly imagine they raise the temp inside the trailer, though I do have 7/8" of foam lining the walls for insulation.

[Eddie Longest]

Slim Potato Head and his Aliner clips of You Tube installed raised flexible panels
on his trailer. He has several clips on his installation but the clip on a failed panel might be of interest if considering flexible panels. His other solar clips describe why and how he installed and repaired his panels.

Eddie

https://www.bing.com/videos/search?q...B&&FORM=VRDGAR

[tractors1]

If you use a 3M VHB type tape, you can order the tape by thickness and eliminate the polycarb risers. For example, the primary tape I use with my products is part number RP-45 where the "45" indicates the overall thickness (0.045 inch) of the tape. Run the tape strips fore-and-aft and you'll have a flow path for cooling, particularly when traveling.

[Markz]

Originally Posted by tractors1

If you use a 3M VHB type tape, you can order the tape by thickness and eliminate the polycarb risers. For example, the primary tape I use with my products is part number RP-45 where the "45" indicates the overall thickness (0.045 inch) of the tape. Run the tape strips fore-and-aft and you'll have a flow path for cooling, particularly when traveling.

Do you think double-sided foam tape might work as well?

Sent from my SM-G930V using Fiberglass RV mobile app

[tractors1]

Originally Posted by Markz

Do you think double-sided foam tape might work as well?

Sent from my SM-G930V using Fiberglass RV mobile app

3M VHB tapes are double-sided foam tapes. AM Solar has been using it for many years. https://amsolar.com/rv-mounting-accessories/91m-vhb

[Jim Bennett]

Originally Posted by Eddie Longest

Slim Potato Head and his Aliner clips of You Tube installed raised flexible panels
on his trailer. He has several clips on his installation but the clip on a failed panel might be of interest if considering flexible panels. His other solar clips describe why and how he installed and repaired his panels.

Eddie

https://www.bing.com/videos/search?q...B&&FORM=VRDGAR

Those are the older technology semi-flexible panels.

[ZachO]

I wouldn't worry at all about panels on the roof increasing camper temperature. The temperature of the panels themselves, though, is really important, and any solar design always takes into account keeping the panels as cool as possible for best performance. Charging goes down with increased heat, so there's always some gap left for air flow.

But you can't argue with results. Jim's setup clearly works great for him, so it works!

[stude]

I have now talked to several solar dealers who also install them and 5 out of seven say leaving a gap for air movement is important to keep the area under cool. I use Rigid for this reason only, at one time the Flexible S. Panels were not that good but maybe now they are better.
Stude

[honda03842]

Originally Posted by Markz

I am interested in installing a pair or flexible solar panels to the roof of our Boler.

I am also concerned about providing ventalation under the panel and the panels blowing off while traveling.

I was thinking about installing the panels on ribs that run front to back, parallel to the roof lines.

The panels are made from polycarbonate and I was thinking about making ribs out of polycarbonate as well. Gluing the ribs between the flexible panels and the roof via high strength marine epoxy.

My thought was to raise the panel off the roof 1/2". My fear is that they would catch do air and break off on the highway.

Any thoughts?

I've had flexible panels bonded to my roof with Scotch Exterior double sided tape for about 7 years. I did not make an airspace between the panel and the roof. I ran the tape around the edge of the panel, stood it up on one edge and laid it down. Link to tape follows.

https://www.amazon.com/Scotch-Perman...+exterior+tape

We travel 7 months of the year through all kinds of climates on rough and smooth roads. Absolutely never a problem.

We also use it for holding items to the walls, counters, and dash of the car.

One nice part of the flexible panel is that it does little to disrupt the airflow across the top and weighs very little.

i did not caulk the edges of my panels.

As to heat issues, I haven't noticed any.

[gordon2]

[QUOTE=ZachO;708665]... Charging goes down with increased heat, so there's always some gap left for air flow.
.../QUOTE]

And decreases panel lifetime.

Panels normally have progressively lower output as they age. As I understand it, the hotter they are, the faster they age. So if you want the most bang for the buck, plan for air circulation under the panels. (But if you are going to get rid of them in under five years, it likely makes little difference).

[Raz]

[QUOTE=gordon2;708782]

Originally Posted by ZachO

... Charging goes down with increased heat, so there's always some gap left for air flow.
.../QUOTE]

And decreases panel lifetime.

Panels normally have progressively lower output as they age. As I understand it, the hotter they are, the faster they age. So if you want the most bang for the buck, plan for air circulation under the panels. (But if you are going to get rid of them in under five years, it likely makes little difference).

Good post. Solar panels are semiconductor. Heat changes their chemistry. Failure can be gradual or in the case of thermal runaway, instantaneous. No way to tell. I would guess you could monitor the health of a panel by yearly recording Voc and Isc. I would expect both to decline as the panel ages.

I have two concerns with using vhb tape. One is failure of the gel coat-fiberglass bond and the second is removal of the panel. I would expect the trailer to easily out last the panel. Someone is in for an interesting job.

[Markz]

There must be a method of effectively removing VHB from fiberglass?

[minke]

Originally Posted by Markz

There must be a method of effectively removing VHB from fiberglass?

I use a product called Steelie Dash Mount Kit Plus to hold my GPS and ham radio control head on my truck's dashboard. The steelie products ( Steelie Dash Mount Kit Plus ) use VHB tape. The instructions for installation and removal are at http://www.niteize.com/images/STCKP-Instructions.pdf . This is of course on a much smaller scale than support for a PV panel.

Before relying on VHB I would spend some time at the 3M website to learn everything I could. I would also have high expectations due to all the successes I've read about.