Tutorial: Installation of the Roof Fan and Solar Panels (Step by Step)

How to install a roof fan and solar panels on your converted van: Complete guide

Introduction: Transform your Sprinter van into a converted van by installing a roof fan and solar panels.
In this guide, we explain step by step what you need to successfully complete this essential project for your van's layout.

Note that this mounting method is universal. You can find here our fans in stock and here all our sealants and promotional items.

Necessary materials

• 40 x 40 fan for converted vans
• 200W solar panels
• Aluminum roof rails
• Bolts, nuts, and rivets
• Tools: drill, jigsaw, screwdriver, etc.

Installation steps

Choosing the fan

We chose to use the model 40x40 with 3 speeds, which is mid-range. A popular choice is the Carbest Vanvent, which is high-end with interesting features including hot air extraction and rain detection.

The 40x40 fan has three speeds, a reversible direction allowing it to suck in or expel air, and a built-in thermostat for automatic activation based on the set temperature. It offers all the basic features needed at a price about a third lower than high-end models, perfect for our installation.

Marking and cutting

The fan comes with a foam protection that we can use to position the cut on the roof and mark the cutting lines.

Some first-generation Sprinter vans had a section on the roof, adjacent to the sliding door, where an original fan or passenger air conditioning unit is mounted. This can be a perfect place to mount the fan without interfering with the ribs or other structural elements.

Additionally, we will install sliding windows towards the back of the van, so placing the fan here allows for sufficient distance to achieve good air circulation when the windows are open at the back.

After marking with a marker, we removed the template and applied painter's tape along the perimeter to avoid scratches caused by the jigsaw's foot when cutting the hole.

Cutting the sheet metal

Using a step drill, we drilled a ½" hole near each corner so that the jigsaw could pivot from side to side. We used a fine-toothed metal blade to cut the square with a jigsaw. Cutting sheet metal with a jigsaw is very noisy, so make sure to have hearing protection.

PRO TIP: To minimize cleanup inside the van, we taped a large garbage bag under our cutting line to catch the metal shavings.

Before removing the painter's protective tape, we sprayed semi-gloss white anti-rust paint to seal the bare metal edges. Once the paint was dry, we removed the tape and cleaned the perimeter with a simple cloth.

Making the frame

We then cut 2x4cm wooden boards and drilled holes to create a frame for the fan. This frame will be mounted under the fan from the inside, essentially sandwiching the roof wall between the two. It provides additional material for the fan's mounting screws to hold as well as support for the finishing trim once the ceiling panels are installed.

Sealing and installing the fan

We used Sika 521UV sealant. Another popular sealant choice is Sikaflex 522.

After applying the sealant, we positioned the fan ensuring to give it a side-to-side movement so that the sealant could spread.

The hinged part is oriented towards the front of the vehicle. This is important because the fan is a perfect square and can fit in any direction. You want the opening to face away from the direction of travel (i.e., forward), as the opposite direction will create a parachute effect and tear off the cover when driving on the highway if left open.

Securing the fan

While one person holds the wooden frame underneath, inside the van, another must apply a few self-tapping metal screws into the wood. We used standard length screws.

Final sealing

Once all the screws are in place, we taped the perimeter of the fan and generously applied exterior window sealant around the holes and voids. The goal here is to reduce any chance of leaks.
To finish the installation of the fan, we removed the cellophane and enjoyed the result!.

Installation of roof rails and solar panels

Rather than using standard roof rails, we used low-profile aluminum profiles 150cm long. Unlike newer models, the 2005 Sprinter does not have original mounting locations. Therefore, we used three M8 riveted nuts to secure each of the rails. Using a drill bit, we drilled a hole large enough for the threaded rivet to fit perfectly.

Installation of threaded rivets

There is no need to buy a special tool for threaded rivets; you can use a bolt with a different thread than the rivet, a few nuts larger than the bolt (we used M10 nuts), and a few washers.

Once all the pieces are threaded together, simply insert the assembly into the hole and tighten the bolt using the impact drill while holding it straight with the nuts using the wrench. As you tighten gradually, you will start to feel the compression of the rivet.

Once the tightening resistance increases again, you can simply loosen the bolt and the rivet will stay in place. Make sure not to over-tighten the bolt, as this could damage the rivnut's flanges once compressed and it would be difficult to remove it.

Securing the solar panels

Using 4cm aluminum bar profiles, we cut them to length to have four pieces 2 feet long that we can attach to the short sides of the panels. We made oblong holes on the mounting sides on the rails by measuring two equidistant points, drilling holes slightly larger than an M8 bolt, cutting the material between the two holes with a jigsaw, and smoothing the edges. It is not absolutely necessary to make slots in the holes, but we thought it would give a little more adjustment possibility during mounting.

Since the length of the angle aluminum is shorter than the width of the panels, we just centered it roughly and transferred the hole locations with a marker. Using the same drill bit as before, we used our hand drill to drill the holes we had marked on the solar panels.

We ensured that the holes were aligned by placing the rivets through the aluminum angle and into the solar panels before securing. Then, we secured the rivets using the riveting tool.

If you have never used a riveting tool before, it takes a few pumps on the handle before there is enough tension to deform the tail of the mandrel, which is the piece that sticks out and goes into the tool.

We secured the rest of the brackets with rivets and achieved a fairly solid mounting solution.

Cleaning rust before final solar installation

Before we could finish installing the roof rails and panels, we had to treat all the surface rust on the roof. There are seams where the body sections overlap and are spot-welded together, which is a major water leak issue on some vans. Additionally, for our van, it seemed that someone had gone through something with low clearance and scraped the paint in some places. So we used a wire wheel to remove the rust from the surface and sprayed a coat of rust inhibitor.

We applied a bead of the same sealant used during the fan mounting, Bostik 70-03, on the seams and smoothed it with our finger. Since the sealant can be painted, a nice coat of fresh paint should give it a relatively OEM look.

Mounting the rails

Once we positioned the rails over the riveted nut locations, we slid the channel nuts that will be used to mount the solar panels before tightening the rail mounting bolts.

We used a large diameter fender washer for the mounting bolts to ensure we have enough surface area to provide good clamping force and blue Loctite on the threads to ensure the bolt does not loosen due to vibrations on the road.

Once the rails were secured to the roof, we placed the panels on top aligning the oblong holes on the brackets with the channel nuts. We used a parallel cable harness adapter to connect the two solar panels and routed the output connectors between the two panels.

Mounting and solar panels

As the mounting bolts were a bit short, we used a magnet to hold the channel nuts high enough for the bolts to catch a few threads. We also used blue Loctite on these bolts and tightened them with an impact.

Installation of the cable gland

We chose to place the electrical area towards the middle of the loading area, so placing the cable gland between the two solar panels was the best location for our installation. We used a 1.25" metal hole saw, cleaned the edges with a file, and sprayed the raw metal edges with paint.

Sealing and mounting the cable gland

We installed MC4 connectors on a 12-gauge wire to connect to the parallel harness and passed the wires through the cable gland. We will go into more detail about the electrical setup in another article!

To seal the contact surface, we generously used silicone sealant along the flange and used self-tapping metal screws to secure it to the roof.

Admire the work!

And there you go! The installation was a bit laborious but in the end, it's a valuable investment.

If you liked the project, don't forget to share it. Comments and feedback are always welcome.