Mounting Flexible Solar Panels DIY Truck Camper

We are attaching solar panels to our truck camper with Velcro. Sounds crazy? Let me back up and explain.

Solar panels have become a common upgrade to RVs. They supplement the life of the RV batteries, enable extended camping away from hookups, and offer a renewable and safer alternative to propane and diesel power. That said, solar energy is a rapidly shifting game. Innovations in panel technology make systems more efficient and less expensive. These days, many solar panels may be replaced or augmented within a matter of years. Rather than gluing down a new panel every three years, we want to design a system to install and replace solar panels into our system easily. Sure, it means a lot more work and experimentation, but that’s our style at Roam Lab.

Flexible Solar Panel Challenges

Most flexible solar panels are attached with glue and a few screws. It’s fast and easy. But there are a few challenges that pop up as soon as we wander away from a quick and simple glue and screw solution.

Overheating and the Air Gap

Flexible panels are ideal for curved surfaces such as our Avion but they are known to overheat due to poor air circulation. On a very hot sunny day over the summer, we set our panels on an aluminum surface similar to our camper and found that they quickly reach nearly 140°F.

A common means of mitigating this problem is to add an air gap—a space between the solar panel and the roof to allow airflow and cool the panel. Our solution? Velcro! Sure, we put velcro on our shoes and bags to easily secure and release a temporary connection, but it can be so much more powerful. The Velcro we are talking about uses the molded nylon VELCRO® Brand High Technology Hook (HTH 757) “For heavy-duty applications with little to no cycling” designed for rough outdoor use. A little more on that later.

The Basics of Velcro

We have learned a lot about velcro in the process of this build. There are four main metrics to consider with velcro: cycle life, peel strength, shear strength, tension strength.

All together, we feel comfortable that the panels will be well supported by the velcro alone. But there is one more consideration that inspires some additional precautions.

Highway Conditions

An air gap can turn a solar panel into a wind sail. Cruising down a freeway at 65 mph could be disastrous with the potential lifting force of winds streaming over the camper’s body. So, while the velcro can easily hold the panels in place, we will also add a windbreak to prevent gusts from pulling the panels off the camper.

For this, we are installing an aluminum frame to protect the sides of each solar panel. It’s the final piece in our solar power mounting system. So, we are ready to start building.

Preparing for the Solar Panels

Aluminum Frame

Each panel will be pinned in place with an aluminum frame. In keeping with our original intention, we want this frame to hold the panels snuggly in place and allow the panels to be easily removed and replaced. We settle on a combination of extruded aluminum pieces. Three sides will be secured with a J-bar, which will wrap around the edge of the panel, while the final side will be secured with two angle bars bolted together to make a removable U-channel so that the panel can slip in place.

Tapping

Along with measuring and cutting the bars to size, we also have to tap the sections that will be removable. Using this tap, we can thread holes to receive a bolt. This way, we can make secure the removable sections of the railing with a stainless steel bolt.

Buck Riveting

With everything in place, we return to our trusty buck riveting arrangement. Each rail is buck riveted to the roof. But to minimize the number of holes used (since holes can lead to leaks), we combine this with UHB tape. We secure the rails with the high bond tape and then add a little insurance with some rivets.

Velcro

And now, the main event! With the frames in place, we can start applying the velcro.

Velcro is only so strong as its connection to the items it connects. Fortunately, the adhesive on the back of the velcro strips we are using is ideal for binding to anodized aluminum. So a scrub down with isopropyl alcohol as us ready to start applying the velcro.

We only need a relatively small amount of Velcro to connect the panels to the camper roof. We apply the velcro to the panels’ outer edges while leaving room for any offset for the aluminum rail. We make sure there aren’t any bubbles limiting the velcro and camper surface connection by using a roller to apply even pressure to the velcro. With the velcro strips carefully applied, we set them aside and move onto the final step before installing the panels.

Solar Panel Wiring

With all of this, it is easy to forget about the wiring of the solar panels. We avoid drilling holes in our camper as much as possible. So, we are routing all the wires through a junction box mounted on the camper roof. In the junction box, we connect all the wires to one 10AWG negative and one positive wire before traveling through the camper roof. This will minimize the potential for leaks into the camper. Once inside, the wires hook up the rest of the electrical system via the solar controller.

MC4 Connectors

We use many MC4 connectors so that each solar panel is easy to disconnect from the system. These are industry standard for outdoor solar connections. We connect each panel independently to the system with MC4 connectors to easily disconnect and reconnect the panel when necessary.

Protecting The Wires

All this means that many wires have yards to travel across the camper roof before reaching the junction box. These can be opportunities for branches and other overhead obstacles to rub against the camper roof and snag a cable, damaging the system. So we want to protect these wires as much as possible. Fortunately, we can integrate a lot of this protection with the aluminum frame. Along with snuggly holding the solar panels in place, the removable section also covers a channel for the cables. The wires connect to the solar panels, travel up through the covered aluminum rails, and then make the short hop from the rail to the junction box, relatively protected in the shadow of the roof hatch. (We are still settling on long term solutions for this final stretch of wire.

Installing the Solar Panels

With the velcro attached, aluminum rails riveted, and wires ready for connecting. It is key to have the panels in place before they engage with the velcro. So, we lightly tape a plastic sheet to the solar panel’s back to cover the velcro hooks. Once the panel is in place, we can gently pull out the plastic sheet and push down the panel to engage with the velcro firmly. Once it’s all together, we’ll have to carefully pull up the entire panel if we want to move it.

Next, we connect all the wires to the solar panels. We like to monitor the solar controller app to see increased wattage as each panel is connected. We have a few strategic points where we use zip ties to secure the wires and rout them into and out of the aluminum frame and junction box.

Now, we can screw the aluminum frame together to secure the panels and wires. We have to be very careful not to strip these threads as the bolts are stainless steel, but the frame is a much softer aluminum. So far, it is holding up well!

More to Come

With the panels installed, we are ready for a test drive. As much as we feel confident that we have dotted our “i”s and crossed our “t”s, it’s a hair raised experience. We stick to surface roads for this first trip, gradually working our way on to faster thoroughfares, maxing out at 55mph. When we are done, everything looks to still be in its place.

While we are pleased with the setup’s roadworthiness, we still have upcoming solar panels projects. With fall in full throttle, we aren’t worried about overheating the panels in the near future. Instead, we will be switching gears to some more weatherproofing and insulation work. But we do have upcoming plans to add more than just an air gap between the solar panels and the camper roof.