If you wish to be able to live in a campervan off-grid for short periods of time, or even fully off-grid, solar panels are the way to go.
When starting out with our campervan conversion project, we did some research into the diversity of possibilities that exist these days that would allow us live off-grid for prolonged periods of time whilst living on the road.
The two options that stood out to us where wind energy and solar energy.
Some in-depth research into wind energy showed us that it currently has not yet matured enough to be a cost-efficient and reliable source of energy for a campervan that is continually on the move.
As we plan to be on the road continuously with our campervan, a requisite of our energy system is that it has to be permanently fixed to the campervan and be operational at all times. During our research, we did not come across such a wind-turbine. If you however live off-grid in a fixed location, we do recommend you check them out as there are some great options out there!
Solar panels do offer this option. We therefore, like most other vanlifers, went with solar panels as our energy generators of choice.
Here we’d like to share a step-by-step guide to help you install your solar panels on the roof of your camper yourself.
Sizing your solar set-up
We have managed to install four 100-watt solar panels on the roof of our campervan.
These solar panels will in-turn be attached via a charge controller to our two leisure batteries (you can read more about charge controllers here).
In order to determine the minimal size of our solar set-up, we’ve looked up the average amount of sun-hours per day in Europe (which is the region where we will start our journey). We’ve settled on a rough estimate of about 4 sun hours per day. Which should be easily attainable for us as we do plan to follow the sun along a bit during the year.
We had previously estimated our power consumption when living full time in our campervan – click here for more information about this – which came down to about 930 watt hours.
One last important aspect to take into account are system losses. We were unable to find a generally accepted estimate for system losses. We did however, on multiple occasions, come across the number 30%. So we settled on a system loss of 30%.
System losses can result from for example dirt on your panel and losses due to the transportation of energy via the wires from one place to another in your electrical system.
To summarize, we have 4 sun hours on average, a 30% loss of energy, and a power consumption of 930 watt hours a day.
The minimal size of our solar panels is then:
930/4/0.7 = 333 watt
This value should then always be rounded up to meet your minimum requirement, which resulted in us opting for four 100-watt solar panels. We could have also gone with 350 watt, but due to the share amount of estimates that needs to be done, we rather oversize our system a little than come out too short.
Luckily, we could precisely fit 400 watts worth of solar panels on the roof of our campervan!
So, now that we’ve determined the size of our solar system, it is time to install the panels!
There are a wide variety of mounting options for solar panels available on the market. One has to take into account however, that installing solar panels on the roof of a van is a whole nother story than on a nicely flat roof of a regular camper.
Vans usually come with irregular roofs. Often, ridges run along the roof of the van, from front to back. These ridges often have different elevations, creating a difficult surface to work with.
We eventually went with Z shaped brackets. We opted for these because the contact area of the bracket with the van is very small. Additionally, they can be secured on just about any spot on the solar panels. This allowed us to secure the brackets nicely between all the ridges of the van on even surfaces.
The small space needed to secure each solar panel to the roof allowed us to fit four solar panels on our roof, while still being able to access every part of our roof for cleaning purposes, maintenance, and etcetera.
Z-brackets are thus quite versatile and great for mounting solar panels to the irregular roof of a van. They do however come with one downside. The solar panels cannot easily be detached from the roof, making it impossible to clean the area beneath the solar panels.
Installing the solar panels on the roof
Installing the solar panels on the roof is actually quite easy. Here is a short step-by-step list of how we’ve gone about it:
- Clean the roof of your van;
- Determine the locations of the solar panels on the roof;
- Determine and mark the locations of brackets on the solar panels;
- Drill holes in the solar panels (insert a small piece of wood in between the frame and the panel to prevent possible damage to your expensive solar panels);
- Fit the brackets on the solar panels by use of the included bolts and nuts;
- Attach the solar panels to the roof by use of the supplied self-drilling screws;
- Make the screw watertight by applying butyl kit (After we were done, we got a tip to put a small strip of rubber between the bracket and the roof of the van to prevent any water entering the van or any rambling on the roof whilst driving.);
Wiring in series vs parallel
Once all the solar panels have been installed on the roof, all that is left to do is wire them up. If you only have one solar panel it is quite easy, just connect the positive wire to the positive of your charge controller and the negative to the negative.
When connecting multiple solar panels however, there are two different options to wire them. You can either wire your solar panels in series or in parallel. Each of these options comes with its own set of advantages and disadvantages.
When wiring your panels in series you connect the positive terminal of your first solar panel to the negative terminal of your second solar panel and so forth. This should leave you with a negative wire from your first solar panel and a positive wire from your last connected solar panel.
If solar panels are wired in series, the amps stay the same, but the voltage is additive. So when you connect three 8 amp, 12 volt solar panels in serie, you end up with 8 amps and 36 volt.
Advantage: It results in an increased voltage. A higher voltage means a lower loss of energy in your system and thus a higher efficiency.
Disadvantage: All solar panels form one string to your charge controller. This means that when one of the solar panels is shaded or drops out, the entire system is affected.
When wiring your panels in parallel you connect all the minus terminals of each of your solar panels to each other and all the plus terminals to each other.
If solar panels are wired in parallel, the volts stay the same and the amperage is additive. So when you connect three 8 amp, 12 volt solar panels in parallel, you end up with 24 amps and 12 volt.
Advantage: Multiple pathways to the charge controller. Shade on one of the panels will not affect the output of the other panels.
Disadvantage: the amperage is additive. A higher amperage means thicker cables and thus higher costs, but also a lower efficiency of your system.
Keep in mind the difference in amperage and volts when wiring your solar panels either in series or parallel.
A charge controller is especially important when wiring your solar panels in series due to the fact that the voltage is added up. A charge controller is able to accept a higher voltage and in-turn converts this to the correct voltage of your leisure battery.
We wired our solar panel in parallel because the distance between our solar panels and the charge controller is minimal and therefore the loss in energy is, too. Additionally, we will often drive through and reside in forests and such. Wiring the solar panels in parallel will minimize the loss of energy due to shade.
Here are some blog posts that might be of interest to you if you’re up for some further reading on the subject at hand!
Did you like this blog post and want to read more? Click here to go to our main campervan conversion page! Here, you can find a neatly organized list of all blog posts related to our van conversion project.