Instructions and Tips for Installing Solar Cells on a Campervan

Solar panels offer the simplest and most sustainable solution for autonomously charging a campervan's auxiliary battery on the go. The battery is continuously charged without your intervention, allowing you to use your appliances on the road without starting the engine daily or connecting to shore power.

The idea of tackling the electrics might seem a bit daunting and require some courage for some, but in fact, the work is quite simple and can be done yourself without much effort.

The electrical system in a campervan typically has a voltage of 12V, which is not enough to produce a dangerous current through a healthy person. Of course, certain things still need to be considered to prevent damage to components.

If you don't feel comfortable with it, it's always better to consult a professional in case of doubt.

Vanstudio has compiled the necessary materials, steps, and some helpful tips for you here.

What needs to be considered in advance?

When choosing the right solar panels, the size and power of the solar panels are paramount. This typically ranges between 50 and 200W, and of course, multiple solar modules can be connected in series if more power is needed. There is also a distinction between mono- and polycrystalline modules, which refers to the structure of the solar cell. Simply put, monocrystalline solar cells are more efficient, meaning they provide more power for the same size, which justifies their higher price.

A charge controller must now be connected between the solar modules and the auxiliary battery, which protects and correctly charges the battery.

The selection of the right charge controller depends on the module's power, max. solar module voltage, battery capacity, and charging current. We generally rely on advanced MPPT charge controllers from the Ective brand, as these operate more efficiently than outdated PWM charge controllers. We are happy to assist you in selecting the right charge controller; please contact us here.

Finally, suitable cables are needed to connect the solar module, charge controller, and battery.

 

Before purchasing the materials, the vehicle's roof should be measured carefully. It is important that solar cells are not shaded, not even partially, to ensure they deliver the desired performance. Therefore, solar cells should not be mounted near satellite dishes, pop-up roof hatches, or similar, if no loss of performance is desired.

The solar panel cable must find its way into the vehicle's interior somewhere. The planned position of the charge controller inside the vehicle should be considered, and the shortest possible route chosen. With the help of a roof feed-through, cables can be easily routed inside, and the roof remains sealed.

In addition to the position of the solar cells on the roof, the question of fastening naturally arises. Rigid modules are usually installed, and these require some air between the vehicle roof and the module. Often, the modules are screwed onto a roof rack, which has the advantage that they are easy to remove again. Alternatively, there are mounting kits that are screwed to the solar cell and glued to the vehicle roof.

 

Required Materials & Tools:

- Cleaning agent

- Cordless drill & drill bits

- Solar modules

- Mounts for solar modules

- Body adhesive

- Charge controller

- Cables & adapters

- Cable ties

- Roof feed-through

- Sealant

(Protective equipment: Gloves & respiratory protection when using cleaning agents, if applicable)

 

Step 1: Preparation and Planning

Check if the desired solar cells really fit on your roof and how best to arrange them. Mark (with some tape) the position of the roof feed-through and the brackets, if you are using any.

Note that a solar cell is best positioned in the direction of travel to offer as little resistance as possible while driving.

 

Step 2: Cleaning the Roof

Clean the roof thoroughly, paying special attention to the position of the roof feed-through and the brackets, if you are using any.

The basic rule for all surfaces to be glued is: Clean, grease-free, dry.

Step 3: Attaching the Solar Modules

With mounting kit:

The mounts are fastened to the solar module frame with self-tapping screws. Make sure that the solar module is not damaged during screwing. You can usually screw directly into an aluminum frame, but never into the solar cell itself.

Position the solar module with the bracket on the roof and glue it according to the adhesive manufacturer's instructions.

To save yourself the unnecessary and challenging search for cables under the mounted module, it is worthwhile to secure them beforehand with tape so that they are easily accessible after installation.

The adhesive needs a certain amount of time to cure; here too, the manufacturer's instructions must be followed. The vehicle should not be moved during this period.

 

With roof rack:

Solar modules can be attached to a variety of roof racks in different ways.

Instead of self-tapping screws, it is advisable to drill holes in the module frame and attach them to brackets. With sliding struts, the solar panel can also be mounted recessed so that it does not protrude beyond the roof rack. This reduces air resistance while driving and thus also driving noise somewhat. It also looks nicer.

 

Step 4: The Roof Feed-Through

Now for the exciting part: a hole needs to go into the roof.

A hole is now drilled into the vehicle roof with a drill bit of the appropriate size. Contrary to what might be intuitively chosen, it is advisable to drill the hole on a raised area. Most vans have corrugated roofs to increase stability. Water can collect in the valleys, which is why we recommend mounting the roof feed-through on one of the ridges. The drilled hole should be deburred and in any case treated with sealant, as the sheet metal at this point is now unprotected and could otherwise start to rust.

The roof feed-through is fastened according to the manufacturer's instructions. Usually glued, in rare cases screwed with a suitable seal. Here too, the adhesive manufacturer's instructions must be followed.

Again, ensure that the surface is thoroughly cleaned beforehand and that the roof feed-through is well sealed at the end.

Cables can now be safely routed into the vehicle interior through the roof feed-through.

Alternatives:

Depending on the vehicle, there are alternatives for cable routing that do not require drilling into the vehicle.

- Some customers have reported to us that they routed the cable into the vehicle interior under the tailgate of their VW T6. Top left under the tailgate, there is a factory-sealed cable feed-through for the power supply of the third brake light, lock, and so on, which can also be used for a solar cable. Although we have not yet tested this version ourselves, it seems to us to be a good solution if you do not want to drill into the vehicle.

- From the author's own experience: In the VW T5, the cable can also be beautifully routed in one of the side joints of the windshield into the engine compartment. From the engine compartment, there are already cable feed-throughs to the driver's cab, left below the steering wheel. This also avoids drilling into the vehicle roof.

 

Step 5: Wiring

Laying cables is relatively easy, but a few basic rules, besides choosing the right cable, should be observed:

1. Do not lay cables under tension to avoid stressing the connectors at the ends and to prevent accidental loosening.

2. Protect cables from mechanical impact, meaning do not lay them over sharp edges and ensure that the cable is not subjected to constant movement. Both will fatigue the material and ultimately lead to cable damage. Cable ties help in many places.

3. Protect cables from heat, especially in the engine compartment, this point is relevant.

4. Bonus tip: Always allow enough cable at the connection points of both sides (approx. 30-50cm) so that the connection is easy to attach. Few things are more annoying than a cable that is too short and constantly slips away when connecting.

 

Before all cables are connected, the solar cells should be completely shaded to avoid potential damage. Simply use the cardboard packaging they came in.

Starting from the solar module, the cable is fed through the roof feed-through into the vehicle's interior. Our solar modules almost exclusively use MC4 connectors, which are standardized plug connectors that simplify installation. Another advantage is that MC4 connectors are protected against moisture and dust (usually IP67), and can therefore withstand the increased load on a vehicle roof. Nevertheless, it is advisable to secure the connections laterally under a solar module or, for example, under a roof rack with a cable tie to prevent unnecessary slipping and to provide additional protection to the plug connection.

The connections on charge controllers differ depending on the manufacturer. Some also use MC4 here, but most have simple clamp or screw terminals for the cables.

Two cables run from the charge controller to the battery. There are a variety of terminals for different batteries; a conventional cable with a lug terminal is usually the simplest and safest connection to the battery.

After all cables are connected, each plug connection should be checked again to ensure the cables are seated. If this is the case, the solar cells can be exposed to the sun for the first time. With a suitable monitor, you can now immediately see if everything is working as desired.

 

You have successfully installed solar modules on the roof of your campervan. Your campervan is now equipped with a clean energy source that provides independent power supply.