Flexible solar panels

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nature lover

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Hello friends, I have a conversion van with a very odd shaped fiberglass roof. I am not sure that I trust putting gutter mounts with high posts To mount panels.  Wind under panels could “lift off” when driving fast?  So I am considering gluing flexible panels to the roof that would conform to the shape of the fiberglass. I think I read somewhere that they work better if you have air passing under the panel.  I can’t remember where I read that. And there’s so much on solar on this site and on YouTube that I’m having a hard time finding someone who dealt with this problem. So someone please give me advice, tell me if it is OK to glue flexible panels to the roof. I know if that panel wears out it’s hard to get off. But at my age and with my health and the age of the van I will probably not outlive the panels.  sometimes I think I know a lot about solar from what I’ve read other times the more I read I get more confused.  I am using 150 watt portable panel now and it doesn’t seem to be charging enough and a pain in the butt to keep moving it with the sun. Thanks for any help that comes my way.
 
I've use gutter mount racks to mount 300-400 watt panels up to multiple panels totaling over 1000 watts. No one has called me to say that they have loosen up or flown off. I have also mounted directly to the top or built custom mounts to accommodate for the odd curves. One person ran into a building, smashing a panel and tweaking her custom rack. We took it down, straightened the rack out and installed a new panel in 3 hours.

Flex panels have a lot of disadvantages with heat build up, output and longevity. The last set I pulled up the heat created by them was melting the eternalbond tape used to hold them down.
 
Vehicle steel gutters are surprisingly strong. Contractors put hundreds of pounds of ladders up there on them.i would only use flexible panels if you had no other choice, or maybe gotten them for free.
 
Flexible panels are garbage. I would not expect more than 5 years from them (any brand) and the only advantage they would have on your roof (forming to the contours of the roof) would make them overheat and drop their output sharply.

As has been said, mount them once the right way with proper mounts and sealant and you will most likely never have a problem for 20 years.
 
I used coroplast under my flexible panels on my contoured roof for an air gap.

I would worry about rigid panels getting ripped off by a tree branch (or?) and they would have to be mounted pretty high in my case. YMMV
 
PlethoraOfGuns said:
Vehicle steel gutters are surprisingly strong. Contractors put hundreds of pounds of ladders up there on them.i would only use flexible panels if you had no other choice, or maybe gotten them for free.

I had an 89 Jeep Cherokee Pioneer with 4 Yakima Rack Bars on it. I once loaded around a half ton of wet floor joist, 2 x 10's,  on those four gutter racks. It held great for more than 30 miles on a mountain road. No creaking sounds or nothing. Those a very strong points near the location where roll protection for the vehicle body occurs. I have gutters on my Ford 2006 E-350 Super Duty van. I'm using them to hold tarps for shade. Somebody made a very cool video on how to make your own gutter clamps out of ABS or PVC pipes.  It's a very slick and cheap way of doing this. I'll look for the link to that video if anyone is interested.
 
B and C said:
I used coroplast under my flexible panels on my contoured roof for an air gap.

I would worry about rigid panels getting ripped off by a tree branch (or?) and they would have to be mounted pretty high in my case.  YMMV

That is a good idea!  That solves the air gap problem, but you still have an inferior product that costs 2-3x more and doesn't last anywhere near as long.

Any tree branch that can rip a rigid solar panel from a mount in a roof gutter will 100% destroy a flexible solar panel, too.
 
I also used industrial strength velcro to "glue" the panels down around the perimeter but still leaving openings for airflow. The velcro is about the same thickness of the coroplast as a bonus. Panels can be replaced pretty easily if push came to shove and they hug the roof.
 
I have flexible solar panels on my kurbmaster they have been there for at least 10 years, still working good, no issues with heat, glued directly to alluminium roof.
 
B and C said:
I used coroplast under my flexible panels on my contoured roof for an air gap.

I would worry about rigid panels getting ripped off by a tree branch (or?) and they would have to be mounted pretty high in my case.  YMMV

These were replacements for your original set of flex panels. How did you have them glued down and why did they need to be replaced?
 
jimindenver said:
These were replacements for your original set of flex panels. How did you have them glued down and why did they need to be replaced?
Industrial strength Velcro around the edges.  The Velcro never let loose and was hard to remove, ask Maki.  The original pair had one connector box that was not glued to the one panel very well and while sitting in my backyard for two years must have come loose in this south Texas heat.  The rocking back and forth in the wind on the drive to Q broke one of the copper buss (thin copper) bars that went from the diode/wire junction box and broke right at the panel.  Non-repairable.  I gave the other panel to Jacque to use as a portable.  I also carry two more in my basement.  I have to bend them a little bit to get them in and out.  They are still going strong,  Rigid panels would never fit in there unless they were less wattage.  Comes in real handy when I park in the shade and winter in Q.  I run a series parallel setup.

I turned the new panels 90 degrees from the old ones to keep the wires parallel with the side of the van so the wind doesn't buffet them so much while driving.  The new panels have a different diode/wire box that appears to be better.

I do love my ultra low solar panel profile though.  You really have to look to tell I have panels up there.
 
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