Installing solar panels on a camper van or RV roof can feel like the most daunting task when building a van’s electrical system. There’s lots of wiring to take care of and drilling holes on your vehicle’s roof is stomach churning.
But in this solar panel installation post, we will guide you step-by-step to achieve the following:
- Securely attach solar panels to your van’s roof while minimizing risk of water leaks.
- Connecting your solar panels to your camper’s batteries to charge them.
Along the way, we’ll provide practical diagrams and recommend useful products to help with your own solar panel installation process.
So if you’re ready, let’s get started!
DIY Solar Build Series
Install Solar Panels to Camper Van Roof
In this section, we detail how to securely attach solar panels to your roof.
Step 1: Test Your Panels For Functionality
Realizing you have a defective solar panel AFTER securing it to your roof isn’t ideal. So make sure your panels are functional once you get them out of their shipping box.
To properly test your panels for functionality, it’s best to use a digital multimeter.
Steps To Test Your Panels
- Place your panels under sunlight to begin electricity production.
- Locate your panel’s ‘Pmax voltage’.
- You can find this on the instruction manual or even the product page on Amazon.
- Your panels should get a reading close to it’s Pmax under ideal situations (clear sunny day & pointed directly at the sun).
- Set your multimeter to read the appropriate voltage range.
- Note: In most cases it should be set to 200 volts.
- Attach the ends of the supplied red and black wires to the multimeter device and the other ends (the probes) to the solar panel’s wires.
- Note: Each panel will come with MC4 connectors attached to their supplied wires. So you’ll likely you’ll have to search for the metal conductors inside the MC4 connectors to touch the probes to.
- Compare the panel’s voltage reading to the panel’s theoretical voltage Pmax.
- The goal should not be to 100% match the Pmax voltage, but to get close. Real world data never quite matches data from a lab.
For more, HandToolsForFun has a good post on using a multimeter to test your panels.
Step 2: Attach Z-Brackets To Solar Panels
Attach Z-brackets to the aluminum frame of your solar panels. Unfortunately, most panels do not come supplied with the appropriate hardware to be installed on a camper van.
You’ll need to purchase one set of mounting brackets per solar panel you have.
To attach, simply affix the Z-brackets, using the small bolts (with washer and nut), to the existing holes on the solar panel’s aluminum frame.
Step 3: Adhere VHB & Butyl Tape To Z-Bracket Feet
When installing solar panels (with mounting Z-brackets), most people would simply place the bare Z-bracket feet right onto the van’s roof.
We are NOT going to do that, however, because we want to:
- Create a stronger bond to the roof than with only screws,
- Form a waterproof seal to prevent leaks
Therefore, in order to create a strong & waterproof bond between the solar panels and the camper van’s roof, we adhered a combination of VHB tape and butyl tape to the bottom of the Z-brackets.
Z-Bracket Feet Diagram
Below is a diagram we created to show how the underside of each Z-bracket foot should look. This is the side of the Z-bracket that will adhere to the vehicle’s roof.
For a super strong bond to the van’s roof, we placed 3M VHB Tape in the middle of each foot (red region).
For a water-tight seal, we placed Butyl Tape around the prefabricated screw holes on both ends of the Z-bracket (grey region).
This way, the butyl tape will act as a waterproof seal around the screw holes and the VHB tape in the middle will provide additional adherence while driving.
Step 4: Place Solar Panels On Camper Van Roof
The panels are now ready to be hoisted onto your van roof for installation.
Because both the VHB and Butyl Tape are on the Z-brackets, you’ll want to place the solar panels in the exact spot you want them located. Once you place the panels down, it will be difficult and messy to re-locate them again.
Step 5: Drill & Secure Solar Panels To Van Roof With Screws
The Z-brackets come supplied with screws.
Eight screws are supplied per pack, so two screws per mounting Z-bracket.
The screws are ‘self-tapping’, which means the screws should drill through your van’s sheet metal roof without the need to dril pilot holes first. But we drilled pilot holes anyway to make the process easier.
When you drill the screws through the roof, you’ll notice that the butyl tape compresses and begins to get squeezed out the sides of the Z-bracket feet. This is a good sign and tells you that a water-tight seal is being formed around the screw hole.
Step 6: Cover Z-Brackets With Lap Sealant
Once the panels were screwed down, we extruded Dicor Lap Sealant all over the Z-brackets for an additional layer of water-proof protection.
We really like this particular lap sealant because it’s quite liquid, which makes it easy to apply onto surfaces and easily smothers all the gaps and crevices to create a tight, waterproof seal.
Step 7: Let Everything Dry & Cure
As a last step, we covered our roof with a tarp for 48 hours to allow the VHB tape, Butyl Tape, and the Lap Sealant to fully cure.
Congratulations! You’re finished installing the solar panels to your van’s roof. Give yourself a quick pat on the back because that’s only the first half of the solar system installation process.
Solar Panel Installation Video: Similar Process
Vanessa and Adam’s YouTube channel is one of our favorite places for van build information. The quality of their build videos are some of the best we’ve seen.
Their solar panel installation process differs slightly from ours, but the idea is the same. It’s worth a watch.
Video starts at 9:45.
Extra: Installing Flexible Solar Panels On Van Roof
We don’t have flexible panels on our roof, but if we did, we would use the below video as our guide.
Flexible solar panels often suffer damage from excess heat because these panels cannot easily dissipate the heat beneath them, unlike rigid panels.
But ‘RV With Tito’ seems to have found a solution to this problem. Enjoy!
After installing solar panels on your camper van roof, you’re ready to connect them to your batteries.
Connect Solar Panels To Electrical System
Once your solar panels are attached to your camper van’s roof, the next step is to connect the panels to your van’s electrical system.
Completing this step means you can begin charging y our batteries from the sun. Pretty cool!
Below, we detail, step-by-step, how to connect your solar panels to your batteries. This includes:
Step 1: Connecting Multiple Solar Panels Together
If you have multiple solar panels on your van’s roof, you will first need to connect them together.
Just like with batteries, you can connect the panels either in “series” or in “parallel”.
Connect Panels In Series or Parallel?
Whether to connect your panels in series or parallel is a sensitive topic for solar enthusiasts within the van life community. Each side has their ‘fool proof’ reasons as to why they’re right.
Let’s take a quick look.
Connecting solar panels in series means the voltages across the panels gets added together. But amps stays the same.
Connecting solar panels in parallel means the amps across the panels gets added together. But voltage stays the same.
Nate, at Explorist.Life, has a great post about the differences between series and parallel regarding solar panels and camper vans.
Do You Need Fuses For Your Solar Array?
Adding fuses to a solar array can be cumbersome and adds additional cost to your total system. But fuses are an important part of any electrical system to keep you, and your camper van, safe.
Luckily, according to National Electric Code, you do not need to fuse your solar panel system if you satisfy any one of the three situations below.
- You only plan to have a single solar panel,
- Your solar panels are wired in series,
- You will only have maximum two panels wired in parallel.
Our Solar Array Connection Choice
Although Nate from Explorist.Life is passionate about connecting his panels in series, we opted to connect our two solar panels in parallel. This was for two important reasons:
- The ability to charge our batteries in partial shading environments was important to us, and
- If you only connect two solar panels in parallel, you do not have to worry about additional fuses or calculating required wire gauge size.
- Tip: Make sure your two solar panels are below 200-watts each and use 10-gauge wire for your connections.
What You'll Need To Connect Your Panels In Parallel
Note: The following instructions are to connect two solar panels together in parallel.
The 2-to-1 branch connectors work great if you have two solar panels on your roof.
But if you have three, pick up a 3-1 branch connector instead.
How To Connect
We relied on these three tools to connect our solar panels to our camper van’s electrical system.
To connect solar panels in parallel, take all your black solar wires and combine them into the corresponding branch connector so that there is a single negative output line.
Do the same with your red solar wires so that there is only a single positive output line.
Step 2: Connecting Panels To Solar Charge Controller
After connecting both the positive & negative branch connectors to the solar panels, we now have a single positive connection point (red) and a single negative connection point (black).
Connect Positive & Negative Wires To Branch Connectors
What You'll Need
For an excellent video on how to crimp MC4 connectors onto 10-gauge wire ends, see the below video from LDSreliance.
Pass Red & Black Wires Through Roof Into Van
Now you have a single red line and a single black line on your van’s roof.
The next step is to bring these two wires through the roof and into the van.
To achieve this, we first passed the red & black solar wires through a solar entry gland.
Steps To Complete
- Drill 0.5″ hole on your roof at the spot where you want to thread your wires through.
- Thread your two red & black solar wires through the solar entry gland.
- Thread the wires through a 0.5″ rubber grommet.
- Bring the red & black solar wires through the 0.5″ hole
- Cover the sharp hole edges with the rubber grommet
- Adhere the solar entry gland on top of the hole with the provided sealant.
- Extrude Dicor lap sealant over entry gland edge.
Connect Solar Wires To Solar Charge Controller
Now that the positive & negative wires are inside the van you can now connect them to the solar charge controller. But first…
What You'll Need
Simply connect your red and black wires directly into a solar charge controller.
In our Victron charge controller, the input values are labled as “PV +” & “PV “.
Side Note: We really like our Victron Solar Charge Controller because it is Bluetooth enabled and you can download Victron’s smartphone app to help keep you on top of your daily solar energy harvesting.
Step 3: From Charge Controller To House Batteries
Installing a Circuit Breaker
In order to protect your solar charge controller from unexpected surges from your batteries, it’s a good idea to include a circuit breaker on the battery side of the charge controller.
Simply put, the amp rating of the circuit breaker you need should match the amp rating of your charge controller.
Connecting To The Batteries
After the circuit breaker, you’re finally ready to connect the red & black solar wires to your batteries. Now you can finally start charging!
In our situation, instead of connecting directly to our batteries, we connected our solar wires to our positive and negative bus bars. Because our bus bars are already connected to our batteries, which you can read about in our camper van electrical system setup, connecting our panels to these bus bars is equivalent to connecting straight to the batteries.
There you have it, you’re camper van solar panel installation is complete!
The End Result: Final Solar Installation Diagram
When you’re all finished, your camper van’s solar system should look something like the diagram below.
DIY Solar Build Series
We hope you enjoyed reading and found the information helpful to install solar panels on your own camper van. Below are several suggested posts for continued reading.