Mounting Solar Panel to Roof Rack (Under Rack + Slideout)

You can install solar panels underneath your roof rack in a few ways. This allows you to generate all the power you need while maximizing your cargo potential.

This solution might not be for everyone, but it’s an excellent option for people looking to get that much more energy into their van. 

It’s surprisingly easy to mount a solar panel underneath your roof rack. All you need to do is measure ahead to ensure that everything will fit in place and follow the manufacturer’s instructions for both the solar panel and the roof rack.

We’ve also got a few tips and tricks for DIY alternatives to mounting a solar panel underneath a roof rack. 

Van life is all about independence, and it’ll blow your mind how free you can feel when you start generating energy for your van without compromising storage.

Can I Mount a Solar Panel Under a Roof Rack?

Yes, you can mount a solar panel under the roof rack of your van. However, there are a few considerations you’re going to need to make before you start this project.

Mounting a solar panel underneath your roof rack has some unique challenges that more traditional mounting setups don’t have to consider.

Getting the Power You Need

The first and most important thing you need to consider is your power needs.

Mounting a solar panel underneath your roof rack means intentionally limiting some of the sunlight that will make it down to your solar panel. This is going to cut into your overall power gain.

For some people living a 24/7 van life, this might be too much power loss to tolerate.

Other van owners who use a lot of electricity might also find that the amount of power they lose isn’t worth having solar panels underneath the roof rack.

The last power-related thing to consider is that certain solar panels lose efficiency dramatically when in partial shade.

Monocrystalline solar panels see their overall energy generation drop off considerably when they don’t have access to full sunlight.  

See also: Mounting Solar Panels: A Complete Beginner’s Guide to Installation

Solar Panel Durability 

Another consideration to make is solar panel durability.

Solar panels are designed to stand up to pretty much anything the weather can throw at them. They are, after all, designed to be outside all day and night and in tough weather conditions.

However, solar panels aren’t designed to double as a roof rack. There’s always a chance that a stray tent pole or a sudden shift in your roof rack’s load could seriously damage your solar panels.

Your Roof Rack

It would be best to consider the roof rack you’ll be mounting your solar panels under and what load is typically on your roof.

If you’re kayaking and your roof rack is almost always loaded up with gear that will stop light from getting to the solar panels, you might not see much gain from installing solar panels underneath your roof rack.

Your roof rack supports also needed to be mounted far enough apart for you to install solar panels underneath them. You might only be able to get a small solar panel underneath your roof rack.

This could still be worthwhile as it will offset the charging of many electronic devices and save your battery from that much use.

Here are some mounting options that will make the following steps easier;

We bet you’re ready to work installing solar panels underneath the roof rack. Here’s how you can do it. 

How to Mount a Solar Panel Under a Roof Rack

You’ll be glad to know that mounting a solar panel underneath your roof rack is actually pretty easy. The trick of this comes down to an old carpenter’s rule that we’re going to adapt for van life: “measure twice, cut once.”

Here’s how you can mount a solar panel underneath your roof rack.

  1. Your first step is going to be to measure everything. You want to know how much surface area you’re working with on your roof, the space between your roof rack’s mounting, and the size of the solar panels.
  2. Next, you’re going to dry-fit everything. Make sure that the solar panel mounting fits underneath the roof rack, and that they both fit on your roof. Don’t settle for less here. A minor fit problem in your driveway can become a major hazard when doing 70 mph on the highway. 
  3. Mark any holes you need to drill with a sharpie marker while you are dry fitting the solar panel and the roof rack. Don’t forget the holes in the solar panel’s cabling! It would be tough to drill those holes once everything is in place. 
  4. Mount your solar panel first by bolting the solar panel mounts onto the roof. 
  5. If you want some extra security, clean the solar panel mounting brackets and the roof with rubbing alcohol, let them dry, and glue them together with adhesive, such as Loctite, in addition to bolting them down. 
  6. Run the cables for your solar panel into your van. 
  7. Install any waterproofing you’ll be using for the solar panel. This includes any waterproof gaskets you’ll be using for the solar panel’s cabling.
  8. Fit the roof rack over the solar panel. Make sure to have a friend help you to avoid damaging the panel. 
  9. Bolt the roof rack down into the holes we drilled in step 3. 
  10. Examine the solar panel and roof rack to make sure everything fits just how you want it to. 
  11. Run a bead of caulk around where the solar panel and roof rack mounting brackets meet the van. This will go a long way to preventing leaks.
  12. Let the adhesive and caulk fully cure based on their manufacturer’s instructions. This is typically no longer than a few days. 

Now you’ve got a roof that stores your gear and generates your power. What more could the modern van nomad ask for? 

Well, what about a slide-out solar panel? 

How to Mount a Slide-Out Solar Panel Under a Roof Rack

We’re not through yet. There’s an innovative way that you can mount a solar panel under a roof rack that dodges all the problems of having your solar panels in partial shade.

Here’s how you can mount a slide-out solar panel underneath your roof rack. 

  1. You’re going to need a sliding mount to start this DIY van project. Dunn and Watson make a sliding mount designed for 100 watt solar panels that is perfect for this job.  
  2. If you want to take an even more DIY approach, Dunn and Watson sell fridge slides designed for industrial fridges and freezers but make great DIY sliding mounts for solar panels. 
  3. The first step is to fit your solar panel to your DIY sliding mount. Make sure that any cables can reach back into your van even when the slide is fully extended. 
  4. Dry fit the sliding mount onto the roof of your van and mark any spots where you need to drill holes for the mounting brackets. 
  5. Now, get your roof rack and dry fit that as well. Ensure that the mounting holes for the roof rack and sliding mount don’t overlap. If you’ve already installed a roof rack, you’ll be able to clearly see where that lines up with your slide-out solar panel. 
  6. Drill holes for the roof rack and sliding mount brackets. Also drill any holes you’ll need to run cabling from your solar panel into your van. 
  7. You can use an adhesive like Loctite Marine PL Adhesive to increase the bond between your roof and your solar panels and roof rack, but it makes them much harder to remove later. 
  8. If you do use adhesive, clean any surfaces you are gluing with rubbing alcohol and let them dry before using the adhesive. Remember, if you glue to dirty surfaces together you’re actually just glueing dirt to dirt rather than bonding the roof and rack to each other. 
  9. Bolt the sliding mount for your solar panel onto the roof of your van. 
  10. Run the solar panel’s cables into your van.
  11. Seal the areas near the mounting brackets with caulk to prevent future leaks. 
  12. You can use rubber gaskets to seal the holes where your cables enter into your van. This is better than caulk or putty as it gives the cabling some extra slack in case it gets pulled around. 
  13. Fit your roof rack over your solar panel and bolt it in place. 
  14. Follow step 9 again, but seal the roof rack brackets this time. There will be no leaks in our van! Allow the caulk and adhesive to cure based on their manufacturer’s recommendations before you head out on the next adventure. 

Before heading out on your next adventure, test out this new solar panel setup.

The best time to find out that this solar panel setup doesn’t work for you is when you’re at home and parked in your driveway rather than when you’re camping 30 miles away from when you last had cell service. 

Alternatives to Mounting Solar Panels Under the Roof Rack

The simple solution to mounting a solar panel underneath your roof rack might be to try out one of the alternative options.

Here are a few alternative solar panel mounting techniques that can save you the hassle of trying to have a roof that doubles as gear storage and energy generation.

  1. Given that solar panels on vans are mostly used to offset the lack of charging while parked, you can always have solar panels stored on your roof rack that you take out once you’ve stopped at your next destination.
  2. Certain types of panel vans can support solar panels installed on the side. You can either change the angle at your van to catch the rising and setting sun or install your solar panels with a kickstand to pop them out once you are parked and catch more rays. 

ACOPOWER 500 Watts 12/24 Volts Polycrystalline Panel Solar RV Kits with 40A MPPT LCD Charge Controller/Mounting Brackets/Y Connectors/Solar Cables/Cable Entry housing

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Elliot has 20+ years of experience in renewable technology, from conservation to efficient living. His passion is to help others achieve independent off-grid living.

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