Stephen Rajeckas – Pro Energy Advice

Most roofs are straight. They might be level or angled, but usually there is a flat surface on which you can fix a set of solar panels. But now and then you will run across a roof that is curved. This is especially true with vans and recreational vehicles that are designed to be aerodynamic. The flat shape of the panels doesn't fit the curves of the roof, which can make installing panels a bit of a puzzle. You can install solar panels on a curved roof. You might need to improvise a bit, but it is possible to devise a set of brackets and other supports that allow you to firmly seat your solar panels on a curved roof. The biggest challenge will be making sure the support structure is solid. This article will talk about your options when you are dealing with a curved roof. There are creative ways to set up supports, and flexible solar strips can bend to fit a curve. Since this comes up so often with campers, vans, and other RVs we will talk a little bit about the different materials used in RVs, and some of the challenges involved with integrating solar panels into your RV's electrical systems. The Challenge With Placing Solar Panels On Curved Roofs Curved roofs can be a challenge. Solar panels are rectangular, with flat sides that don't fit on curved surfaces. There are essentially two ways to deal with this problem. The first is to set up a rack that you can bolt your panels into. The second is to use flexible solar cells that you can bend to fit the curvature of your roof. Though special mounting brackets might not be elegant, they are often the better approach in terms of efficient power generation. Trying to fit solar cells around curves means some will be oriented in different directions. That means different cells will receive different levels of sunlight. The curve might even put some cells in the shadow. Solar panels work better when all cells get the same level of exposure to the sun and put out the same level of power. You may be better off with flat panels pointing in the same direction. Some specialized buildings do have curved roofs. And there are some extreme examples where solar power won't be practical. A grain silo might have a hemispherical top where the curve is too extreme and the overall area is too small. But curved roofs can be dealt with. Here's one example from India, where solar panels were set up on a manufacturing plant with a curved roof. Mounting Solar Panels on Your RV Most of the time the curved roof problem comes up on recreational vehicles. Solar power is an excellent option for RVers, especially those who like to drive into the backcountry, avoiding crowded campgrounds that provide lighting and power. Without access to the grid, these adventurers need their own power source. Solar works very well for many of them. Unlike gas-powered generators, solar power is quiet and environmentally friendly. But the roof of an RV is different from the roof of a home. The roof of an RV will almost always have an aerodynamic shape for travel at highway speeds. That means there will be curves that RVers need to work around. Because they have less room to work with and lower power needs, RV owners will frequently use smaller panels than they would use on the roof of a house: 100 to 200-watt panels instead of the 300-watt panels frequently used on residences. Smaller panels make installation easier as well. What To Do If Your Roof Is Made of Rubber You will almost always need to create some sort of rack or brackets to mount your panels on, but how you fix the whole thing to the roof will depend on the material your RV's roof is made of. If the roof is made of rubber, you will need to bolt the assembly down in the wood or metal frame underneath the rubber. The rubber itself will not be strong enough to carry the panels' weight and will be put to even greater stress when you take the RV out on the road. Highway driving will subject your rig to the equivalent of 60-80 mph winds for hours at a time. This would be comparable to a strong tropical storm or a Category I hurricane every long trip. The force could eventually tear the rubber off of your roof. A proper rigging will involve driving screws or bolts through the rubber. You will want to use a durable rubber-based sealant to prevent water from leaking into the roof. What To Do If Your Roof Is Made of Fiberglass Fiberglass is a tougher material, and you may be able to fix the entire assembly to a fiberglass roof using adhesives. Many RV owners have gotten good results with two-sided Very High Bond (VHB) tape. Either way, you will probably need to install brackets to hold the actual panels steady. There really are no standardized mounting kits, so you will need to use your do-it-yourself skills and improvise a bit. But the rig doesn't need to be very complicated. Here's an example of how one RVer tackled the problem with some aluminum and VHB tape. Flexible Solar Cells: An Alternative To Panels Another option is using thin solar cells. Because these cells come in flexible sheets, they can be bent around all but the tightest curves. These tend to be more expensive, and because your solar cells will be oriented in different directions they may not be as efficient once installed. The technology behind these cells is a bit newer, so the cells might not be as reliable as regular solar panels. On the plus side, the thin solar cells are lighter and their lower profile means they create less wind resistance. You may be able to use adhesives to fix them onto any roof material -- fiberglass, metal, or rubber. Since your thin solar cells create less wind resistance, your gas mileage will remain pretty close to what it was before installing panels. If you aren't confident in your do-it-yourself carpentry skills, this is another option to consider. Power On The Side: Portable Solar Cells While putting solar cells on your RV roof might be handy and save space, if you travel much in hot climates you might want to consider purchasing portable solar cells. You can set these up in a sunny spot while parking your RV in the cool shade. Post-Installation Necessities Whatever type of solar cell you choose, and however you decide to mount it, you should be able to run the wires through roof air vents or the refrigerator vent. (If your RV has a fridge.) You will also want to invest in a charge controller, batteries to store electricity for nighttime use, and an inverter to convert the DC power your solar cells produce into AC power that your appliances can use. Final Thoughts Solar panels can be adapted to all but the most sharply curved roof shapes. Mounting rigid solar panels may require some creativity in terms of mounting, but if that fails there is still the option of using thin, flexible solar cells. This should be especially good news for RV owners, who are most likely to have to deal with curved roofs and benefit from having quiet, environmentally friendly solar power for their long trips far from civilization.