Installing Flexible Solar Panels on a Fiberglass Roof

Flexible-roof-001

Here the flexible panels are after we finished mounting them. You can see the roof vent in the center. There is a curve at the front of the van where the roof angles down. The panels are flexible so they conform to it.

I  believe high-top conversion vans are about the ideal vehicle to live in. They are abundantly available and often at very reasonable prices; they offer a lot of room and the extra height makes them much more comfortable. They have slightly less stealth than other vans, but the difference is very small; so little in fact I don’t think it is an issue. They may also have slightly reduced mpg, but often the difference is very minor. My girlfriend, Terry, lives in a high-top Chevy conversion van and has been stealth parking in Long Beach, CA for a long time. She has never had a problem with being hassled while sleeping. If you are careful any reasonably stealth van should have all the stealth you need. She also gets around 20 mpg on the highway, so the high-top has very little impact on her mpg.

Flexible-Roof

Here you get a better idea of how convoluted the roof is. The whole center area forward of the vent is higher than the rest of the roof and it all angles slightly down to the outside, making it hard to mount fixed solar panels.

She loves her van but it has one problem: the high-top makes it very difficult to mount a solar panel! The majority of fiberglass roofs have several convolutions and often things that stick out of the roof . Terry’s has a vent right in the middle of the roof, many curves, and a low area in the back for a luggage rack. Those things combine to make it impossible to find a space large enough to mount a solar panel. Actually it could be done by custom fabricating different sized feet and mounting the panel high enough in the air to clear the obstructions, but it would be ugly and noticeable, two things that are very bad for stealth and the extra height might cut her mpg. It would also mean drilling holes through the fiberglass roof and reinforcing the roof to be sure the bolts couldn’t pull through.

Terry-Solar-Me-drill

Here I am screwing down the sheet metal onto the plywood. You get an idea of the dip the roof took in the back for the luggage rack. The plywood filled it in and made it level.

We decided the easiest and most practical solution was to use flexible Unisolar Solar Panels. I have worked with them before and liked them and knew they would conform to the curve of her roof. They come in different sizes but we had to get the 68 watt panels because the others were all too long. I suggest most people will be happy with about 135 watts of panels so we bought two of them. They are only 16 inches wide so we could lay one on each side of the van with the roof vent between them. They are also self-sticking; you just peel off the protective backing and lay the glue down on the roof and they bond to it. My research showed that it was an extremely good glue that would not come off. In fact one of the biggest complaints about it was that it would never come off. So if she sold the van, there was no taking the panels off and moving it to the new van. We decided that was okay because she plans on keeping the van for a very long time.

Flexible-Back_use_Best

Here you see the panels at the back which are glued down to the sheet metal which is screwed into the plywood which is screwed into the roof to fill in the gap. A positive and negative wire comes off each panel and then goes into a hole into the van where it runs under the headrest to the solar controller. Notice lots of caulking around the holes.

We had one obstacle to overcome. The roof had a low-area in back where the roof racks were to hold cargo. I was sure that the solar panels were not flexible enough to conform to the nearly square drop of the roof. That would leave a gap between the panels and roof where water and dust could get in and my concern was that over a period of time the glue would slowly un-stick and as it did the flapping would eventually pull the whole panel off. I didn’t want to risk that so we decided to fill in the gap and make it level. We measured it and found out the drop was exactly 3/4 of an inch. So we decided to buy a sheet of plywood and cut it to fit and screw it into the roof. We knew the sun and weather would quickly destroy the plywood so we painted it white with several coats of good paint first. So once it dried we screwed it sown and used plenty of caulk to make sure water couldn’t get in through the screws.  I didn’t know how the glue would adhere to the painted wood, so we decided to put a piece of sheet metal on top of the wood using sheet-metal screws. The metal was a roll of flashing designed for roofs. All of this is readily available at any hardware store.

Terry-Solar-Unpeeling-001

Here we unpeeled the backing to glue the panel down. That’s Bryce holding the ladder, Don standing on the ladder, me in the back, and Brian on the right. We did this at the RTR and I was so busy I was getting overwhelmed. A huge thank you to them all for staying and seeing the project done after I was called away!!

Next we washed the roof extremely well with TSP a cleaner designed to cut grease and grime. After it was totally dry we stuck the panels on. We put the junction box at the back and started there. It was a very simple process. My good friend Brian and I worked together on it. We started peeling the backing and Brian went ahead peeling it back and holding the panel up so it wouldn’t stick at the wrong place. I actually laid down the panel and pressed it into place. The panels are 9 feet long so we had to be careful to keep them straight for two reasons: the area we had to mount it was narrow so we couldn’t miss it, and if it wasn’t straight it would leave a gap where water and dust could creep under. Keeping it straight was the only tricky part but we were able to do it by going slowly just being careful. Once that first one was attached we did the other one and it went easier.

Flexible-Solar-Batteries

Terry had already taken her front seat our to make more room so the batteries went there. I made a little tray to go over her new Full River AGM golf carts so she could use it for more storage.

The simplest way to get the power cords into the van was a hole so we drilled 4 small holes in the roof and caulked them good. We ran the wires under the headliner and out to where we mounted the solar controller. We bought an inexpensive SunForce solar controller from Amazon.com. I know several people who own this controller and they have proven reliable and very inexpensive. I like it because it has a digital display of the batteries voltage and I think being watchful of your batteries voltage is the best way to extend their life and save you some money. We put the controller on the divider between the  cab and living area so she can easily see it. I suggested she keep an eye on it and always keep it above 12.2–and even higher was better. That way her batteries would last a long time! And that is important when you buy AGM golf cart batteries because they are very expensive, $250 each for two. She bought Full River batteries because of their extremely long warranty. She had taken out her passenger seat for extra space, so we put the batteries in there. I had some scrap lumber so I built a little shelf to go above the batteries  to protect them and regain some storage space. I was careful to build it so she could remove the doghouse from here engine without having to move anything. I wanted a fuse between the solar contoller and the batteries to protect the expensive equipment from ground faults or spikes so I bought a 30 amp spade connector and holder at WalMart. I used butt connectors to put it in line on the positive wire from the controller to the battery.

Two last things we had to do before her solar panels were useful: we had to install an inverter and a 12 volt cigarrette lighter plug. I am a big fan of the Cobra 400 watt inverter so we bought one of those off of Amazon and picked up a simple cigarette lighter plug at WalMart. All the wiring for the whole system was 10 gauge because it  doesn’t carry much power. The only real electrical knowledge you have to have for this installation is how to strip and crimp a wire. If you have ever done that before, then this is a simple project. Everything is black-to-black, red-to-red wiring. All you need to do is cut the wires, strip off a little at the end, and crimp on a connector (usually ring connectors but a few butt connectors). Then you take the nut off the bolt and slip the ring over it and tighten the nut back on. Because it is 10 gauge wire go to walmart and buy an assortment of the yellow connectors. The bolts on the batteries are larger so you will need some 3/8 inch ring connectors for them. One of these days I will do a post with videos of how to strip and crimp wire. Once you are comfortable with that, the whole world of 12 volt wiring opens up to you because most of it is just red-to-red, black-to-black.



Bob
About

I've been a full-time VanDweller for 12 years and I love it. I hope to never live in a house again!

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40 comments on “Installing Flexible Solar Panels on a Fiberglass Roof
  1. Michelle(She) says:

    Will be saving this for the future Bob. Thanks for sharing this. Great information!!

  2. Stephen says:

    Nice job! Those flexi panels are still quite expensive in th UK, But the rigid type are really cheep now.We probably don’t get as much sun as you do,but I’ve fitted a 100 watt panel to my roof and it keeps the LB charged up.You can’t beat free electricity! Keep up the good work.

    Stephen.
    Stephen recently posted…Wildcamping.My Profile

    • Bob Bob says:

      You are so right Stephen, you can’t beat electricity! It’s amazing how dependent we have become on all our electrical devices. I can’t imagine a life without them!!
      Bob

  3. I like the flexible solar panels. On the top of my Ford van there are rain troughs and I didn’t consider filling them in until I read your post. I was thinking of just putting the solar panel over the trough but am afraid of wind damaging the leading edge since it would not be adhered to anything. Probably filling it in would be the best option.
    Thanks again Bob for some great info.

    Martin
    Martin Hamilton recently posted…Metabolic Surge [Podcast #002]My Profile

  4. Blars says:

    Unfortuanatly, some motorhomes (like mine) and products designed for them use black for postitive and white for negitive, so you need to wire black to red and white to black. AC wiring uses black for live, white for neutral, and green or bare for ground.

    • Bob Bob says:

      You are right Blars, but for the most part it is black and red from the solar panel to the batteries. In an RV it gets much more complicated and is no longer a simple project. Since I am so unfamiliar with RVs, I don’t pretend to know much about their wiring. But in a van it is simple and so I recommend it to people are even slightly handy.
      Bob

  5. Rolf Fritschi says:

    Hi Bob.
    I kept the height of my van (1999 Chevy 1500) under 6feet 1o inches so I can drive and park in undergroung garages. I spend most of my time in the cities and I didn’t want solar panels. I have a Group 31 AMG batterie directly wired to the alternator to run the fridge and the inside fans. My laptop and phone are charged by the house batterie.(Batteries are seperatet so they discharge each other)
    I’m enjoying all the info I get from your Websites and thank you for that.

    • Bob Bob says:

      Rolf, having a short van is a big plus in the cities. Sounds like you have evrythinge figured out and have a good life!! Thanks for your kind words!
      Bob

  6. Rastaman says:

    Hi Bob,still trying to decide on the van I want to build to travel in, was reluctant to look at high tops because I was afraid of poor mpg. So I am curious what van Terry has and the size motor. Btw most High tops a custom vans with the large windows, what did she do for privacy and insulation?

    • Bob Bob says:

      Rastaman, she has a 1992 GMC Vandura with the 350 V8 and she gets 20 mpg as long as she drives 55. I know that is hard to believe but she swears it is true and I know other people who say the same thing for their Chevy vans with the 350.

      She did what most people do for her windows and covered them with reflectix. The stuff works like magic to keep the summer heat out and actually works well to keep it warm in the winter. She also put limo tint on the windows for privacy. The two work together very well.

      Needless to say, she is very happy with her van!
      Bob

  7. CAE says:

    Hmm, I was thinking about putting these babies on my cabin top of my boat. That’s a lot more elegant than panels fixed to racks along the side. But I have to think about whether or not I’d be trying to step on them in order to get at something…..
    Great food for thought! Thanks.

    • Bob Bob says:

      CAE, they have a reputation for being extremely tough. I first saw one at the Big Tent RV show in Quartzsite where they had a booth set up. They were using one of their panels as a rug and they claimed they had been using it for years and after every show they took it out and plugged it in and it worked perfectly each time. Of course I have no way to know if it was true or if he was lying, but they might be perfect for your boat.
      Bob

  8. Patrick says:

    Hi Bob,
    What is your opinion GMC vs Ford Cargo van? I don’t know which one is better?

    Thanks

    • Bob Bob says:

      Patrick, I honestly think they are about the same. However, I have friends with the newer Chevy 5.3 liter V8 and it gets great gas mileage! Loaded light a cargo van can get 20 mpg on the freeway. If I had a choice it is what I would buy.
      Bob

  9. RV AJ says:

    I cant believe how much cleaner of an installation that is than the conventional panels. I bet its much better on fuel economy as well.
    RV AJ recently posted…Unique RV: New Meaning to Pop-Outs on a Travel TrailerMy Profile

    • Bob Bob says:

      RV AJ there is a lot to love about the flexible panels! A clean and easy installation is at the top of the list! To be honest, I seriously doubt if it would increase mpg, but anything is possible.

      I didn’t mention it but they are amorphous panels and they are supposed to produce more power in the shade and cloudy days than poly or mono-crystalline. If true that’s another big advantage.
      Bob

  10. Lois says:

    Nice post! Solar is on my to-do list for “some day.” My “rig” is a 1965 10′ vintage trailer so I don’t want to permanently install anything on it but I’m thinking there’s got to be a way I can get solar without it being permanent. Thanks for the info!
    Lois recently posted…Calling All Adventurers! Don’t Think That’s You? Read on…My Profile

  11. Bodhi says:

    Thank you for sharing all this information. This blog is far and away the MOST INFORMATIVE reading I do within my blogosphere. I had been reading everything I could about solar panels and how to utilize them correctly and only after reading your e-book did I sit up and say, “I can do this!” It was truly a “light bulb moment”. Thank you, again. Bodhi

    • Bob Bob says:

      Bodhi, those “light bulb” moments are main motivation in all my writing. It’s extremely encouraging for me to hear you had one after reading my book!! From the very beginning I had a two fold purpose: to inspire and educate about vandwelling. Hopefully, when everything falls together just right, the light goes on.

      Thanks for writing in!!
      Bob

  12. Romana S says:

    Very nice writ up Bob. I love your web site. So informative, and like mine, all free.
    I’ve considered using flrxible panels as I have a large roof space and the panels would have a lot lower drag than rigid ones. However there are a couple of factors which have stopped me. First is the cost. Flexible panels usually cost more than twice the price of a similar non flexible panel in Australia. I can buy a 64 watt Unisolar for $225 plus delivery. Yet for the same price I can buy a 200 watt rigid panel with delivery.
    The second is size. Typically a flexible panel would take up 2-3 times the size of a rigid one for the same power output. I figure in the space available, you could have easily mounted 2 x 200w panels, or possibly even more.
    I’m not saying these are bad. It is horses for courses. I still would love to have some of these, I just can’t justify the expenditure and size of them. Mind you on you GF’s van, they are a great option, giving useful power, minimizing drag and looking pretty good too. 🙂
    Cheers, and kind regards,
    Romana

    • Bob Bob says:

      Romana, that’s a very good assessment of some of the negatives and positives of flexible solar panels. Like everything in life, you have to take the good with the bad.

      Keep up the good work on your website!
      Bob

  13. OpenSpaceMan says:

    Bob_ I’ve been reading your blog and got your e-book a while ago and I appreciate your efforts. I traded in my jeep for a E250 extended cab last summer and put some honest time and money into insulation and pre-wiring it for a fridge and LED
    lites…I live in Wisconsin, but have lived on a houseboat on
    Lake Mead in Las Vegas and on a sailboat in the Florida Keys.
    I hope to make some progress this spring and be un-tethered
    by the end of summer and meet up with you some time next winter in AZ…Thanks again for your blog and useful info. Peace.

    • Bob Bob says:

      OpenSpaceman, thanks for buying the book, I hope it was useful. It sounds like you are well along the way to creating a new life for yourself. With your history of living on board boats you must have a lot of Nomad blood in you so this should be like coming home!

      I’m looking forward to meeting you next fall-winter. After Wisconsin, you are going to love the desert in the winter!
      Bob

  14. joey says:

    Hey Bob, just for clarity. That is me holding the ladder,not Bryce.

  15. Ken in Anaheim says:

    Hi Bob; thanks for the article/info. I’ve got a few questions for you;
    1)For the 68w panel, how large of a bundle is it when rolled up ?
    2) Do you know if repeated rolling/unrolling is harmful to the panels ?
    3)(Un-related) have you found a sliding side door or hinged to make much difference on a van ?
    4) (Un-related #2) Does your Dometic refer make ice ?
    Thanks……….BE WELL
    Ken

    • Bob Bob says:

      Hi Ken, 1) The Uniroyal flexible panels roll down to about 16 inches tall by 20 inches wide. 2) I have heard they are extremely durable! 3)I much prefer doors that open out rather than sliding doors. My van has sliding doors and they are okay, but barn doors are far better. 4) Nearly all of the 12 volt compressor fridges (including my Dometic) have a thermostat that you can set between 0 and 50 degrees. So it can be a freezer, or a fridge, but not both at the same time.
      Bob

  16. Bob Bob says:

    Jay, I think you are right, the ribs would become a real problem for the glue in the panels. I wouldn’t trust them without filling them in. You could do what I did and screw on flashing to the roof and attach the panels to the flashing so there wouldn’t be any gaps.

    On Terrys van, just the very front of the panels dips down and is visible from the ground. I think very few people will have any idea what it is and it won’t hurt her stealth. But on a dark blue van, I doubt if anyone would ever see it let alone make the leap that someone was living in the van.
    Bob

  17. Jay says:

    Thanks Bob! I’m afraid to make too many holes in the roof, but I suppose if I used short, self-tapping sheet metal screws and attached flashing to the roof, covered with the self-adhesive solar panels that have super-strong glue, it might make a good, water-tight seal. For added protection, I could put silicone around each of the screws before attaching the solar panels.

    If only the solar panels were a bit shorter so they wouldn’t come so close to the windshield. Otherwise my factory roof rack would hide them well. But, like we said, being a dark blue van should help camouflage the black solar panels. If I end up doing this, I need to save a bit, so it may not happend for a little while, but it’s definitely got me interested in this as a viable solar power option.

  18. Connie Qualey says:

    Bob, thank you so much for putting this out! I’d pretty much decided on these panels too, but had no idea how tough they were to apply! My van is a Chevy, and very similar to your friend’s. it’s 20 ft long, so I shouldn’t ( hopefully) have a problem with the length.
    I have a pre-installed BlueSky 2000E 25amp, 12V solar controller…but having a tough time finding out where the devil they put the connecting wires. Any thoughts on that would be appreciated, since I have no desire to rip the inside of my van apart! It’s a Sporty by the way, and there was a hint that it might be somewhere near the back doors. Haven’t found it yet! The only other logical place would appear to be the ceiling fan outlet.
    The only real question I have is whether I should be purchasing the connectors and 30 feet of solar wiring that Amazon has in their ” bought with” category, or just wait?
    Oh and whether it’s better to apply the panels in sun or shade? I live way up in the mountains so the sun and UV are both strong. Any thoughts suggestions would really be appreciated! And thanks again for showing yhis install! It came at exactly the right time.
    Connie

    • Bob Bob says:

      Hi Connie, it really isn’t that difficult to put them up. Terry’s van had the low spot for the roof rack we had to fill in, but that wasn’t hard, it just added another step. Peeling off the backing and placing the panel wasn’t hard either, we just had to be very careful to keep it straight. Otherwise it would have a high spot water and dirt could get under. Actually it was pretty easy. But you do want extra people for peeling the panel backing so it is easier to keep straight.

      I’m sorry, I have no clue where your wiring might be. Every conversion van company did something different and I have never seen two alike. Wire is fairly cheap, you might find it easier to just run new wire. The Unisolar panels use an older MC3 connector from the panel, so you probably want to get one from them since they are not common anymore. They have been replaced by the MC4 connector.

      I don’t really know about sun or shade, we did it on a sunny day but it was January in the desert and the sun wasn’t very strong. I would think you do not want to do it in the cold so if you are high in the mountains doing it now, I would do it on a sunny day.
      Bob

      • Connie Qualey says:

        Bless you for giving me the the courage! Lol, as always something new is intimidating! However I don’t have a lot of choice sice the woman who had it before me took out the propane! The fixtures are still there, but too rxpensive to do, and she hadn’t kept the tank or parts! It was a great deal however. I know this off- thread, but perhaps you’d be willing to offer some advice?
        Because of her ” adjustments, I have a portable heater ( though it’s well- insulated), and an a/c Starcool – that is missing the propane heating part! I’ve been considering removing it as I rarely use it as is, and could probably better use the space! Is there anything out there that would work for me in a small package, with only the electricity? No rush, as I’ll be saving for my next project after the panels! I’m also looking for a small single burner electric portable stove that’s not too hard on the power supply. I plan to look through what you have shown, just haven’t had time yet. And these questions are for anyone who might have a brilliant idea? I plan to live in my baby, so sooner the better! Thanks again. I know there has to be better stuff out there than I currently have, just a matter of finding the bits and pieces! Thanks in advance to you, and anyone else with helpful ideas. I’d like to find the book you mentioned too, so am hoping it’s here.

        • Bob Bob says:

          Connie, forgive me but I think I missed part of your story. I am assuming you bought a used Class B campervan without the propane system. I would think that adding the tanks back and running new plumbing shouldn’t be too expensive. However, it would be much cheaper and easier to just use a Coleman propane stove and Mr. Buddy portable heater. You could just use the little green bottles without a propane system, but you can also switch over to a bulk refillable bottle. All you need to do is buy a 20 lb bottle at Walmart for $30 and a “T” to run two appliances for $20 and two adapter hoses for $40, and that’s all you need to do to have a propane stove and heater. I do NOT recommend an electric stove, the draw will be too much. It is much better to just use a Coleman stove.

          I’m not very familiar with the Starcool, but I don’t think it is very practical for you. Removing it sounds like a good idea. if you are asking if there is any other Air Conditioning unit that will work off solar panels the answer is a firm NO. The only practical ways to run an air conditioner is from shore power like an RV park or off a generator. For most vandwellers it just isn’t practical to have air conditioning.

          It sounds like you are off to a great start and should have a great van home. Feel free to ask any questions you may have, but give me as much background information as you can!
          Bob

  19. Steve La Cour says:

    First time to read your site. I appreciate your advice and wisdom. I’m soon to be vandwelling as a way of life. I’m excited to begin this new lifestyle. I only need a gypsy minded female partner to share the rest of my life with. Thanks again

    • Bob Bob says:

      Steve I wish you the best in following your dream! You may or may not find your female partner, but don’t let that stand in your way, only when you’re happy being alone are you really ready to be with someone else.
      Bob

  20. Amy says:

    Hi Bob. Great job on the installation. How many years do you think it will be until you need to replace the panels? I bet you are having a great time living the van life. I dream of it too! I’m sure it has it ups and downs, but it sounds so free and fun. Do you have any photos of the inside of your van? Have a great day.

  21. James Wrick says:

    Hello, your article have such a unique content and i love to read it, this is very informative , thank you for sharing with us

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