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Installing Solar Panels On A Camper Van (With Diagrams)

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Installing-Solar-Panels-On-A-Camper-Van

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:

  1. Securely attach solar panels to your van’s roof while minimizing risk of water leaks.
  2. 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!

This post is PART 7 of our 7-part DIY Solar Build Series. Check below to view the entire series.

Install Solar Panels to Camper Van Roof

How-To-Install-Solar-Panels-On-A-Camper-Van-Roof
Installing Two Solar Panels On Our Camper Van

In this section, we detail how to securely attach solar panels to your roof.

For Rigid Panels Only: This section is only intended for those that have rigid solar panels. For those with flexible panels, please refer to the YouTube video we link to at the bottom of this section.

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.

Digital Multimeter

Steps To Test Your Panels

  1. Place your panels under sunlight to begin electricity production.
  2. 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).
  3. Set your multimeter to read the appropriate voltage range.
    • Note: In most cases it should be set to 200 volts.
  4. 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.
  5. Compare the panel’s voltage reading to the panel’s theoretical voltage Pmax.
  6. 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.

Z-Brackets (with hardware)

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.

Z-Bracket Installation Tip: If you plan to install multiple solar panels side-by-side, consider staggering the placement of your Z-brackets so that they don't touch each other when the panels are placed on your roof.

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:

  1. Create a stronger bond to the roof than with only screws,
  2. 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.

VHB Tape

Very strong, double-sided tape for permanent bond to roof.

Butyl Tape

Prevents water leaks around drill holes. Also used in vent fan installations.

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.

Diagram of Mounting Bracket Feet When Installing Solar Panels
Underside of Z-bracket Foot

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

Installing Solar Panels On Our Camper Van
Taking A Break Just Before Screwing The Solar Panels Onto The Camper Van's 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.

Installation Tip: Make sure the red & black solar wires (attached to panels) are brought out from under the panels. You don't want any wires trapped under the panels after the VHB tape bonds the panels to the roof.

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.

Dicor Lap Sealant

* Note: To apply the lap sealant, you’ll need a caulking gun.

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!

What's Next?

After installing solar panels on your camper van roof, you’re ready to connect them to your batteries.

Connect Solar Panels To Electrical System

Solar System Installation Diagram - Overview
Solar Panel Installation Diagram

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

Two solar panels connected in parallel - Wiring Diagram
Two solar panels connected in parallel

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.

Series

Connecting solar panels in series means the voltages across the panels gets added together. But amps stays the same.

Parallel

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.

  1. You only plan to have a single solar panel,
  2. Your solar panels are wired in series,
  3. You will only have maximum two panels wired in parallel.
If you plan to wire 3 or more solar panels together in parallel, you will need to properly fuse your system.
 
So if you must go with 3 or more solar panels, we highly recommend you to connect your panels in series instead.
 
National Electric Code too dry? Give this handy solar fuse information PDF a try to better understand fuse requirements based on the National Electric Code

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:

  1. The ability to charge our batteries in partial shading environments was important to us, and
  2. 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.

Critical To Know: If your solar array is made of 3+ solar panels connected in parallel, you will need to added appropriate fuses to your solar system. This is required by National Electric Code.

We will add a separate post on solar fuses in late Aug, 2021.

Branch Connectors (2-to-1)

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

Connecting Panels To Solar Charge Controller - Wiring Diagram
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

Wire Stripper & Crimper

MC4 Assembly Tool

Red & Black 10awg Wire

MC4 Connectors

Take a strand of red wire & black wire (10-gauge each) and crimp the correct MC4 connectors onto each wire end.

You’ll need a wire crimper and an MC4 assembly tool to complete this step.

Next, connect each MC4 connector to the appropriate branch connector.

Installation Tip: It's important to get a good quality crimp around the 10awg wires or else the wires might slip off due to the constant vibrations while driving. Happened to us!

For an excellent video on how to crimp MC4 connectors onto 10-gauge wire ends, see the below video from LDSreliance.

Important! Only crimp MC4 connectors onto one end of the red and black wires. Leave the other end of the wires bare because they need to be threaded through the van's roof first.

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.

Solar Entry Gland

Steps To Complete
  1. Drill 0.5″ hole on your roof at the spot where you want to thread your wires through.
  2. Thread your two red & black solar wires through the solar entry gland.
  3. Thread the wires through a 0.5″ rubber grommet.
  4. Bring the red & black solar wires through the 0.5″ hole
  5. Cover the sharp hole edges with the rubber grommet
  6. Adhere the solar entry gland on top of the hole with the provided sealant.
  7. 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

Solar Charge Controller

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.

Victron Smartphone App For
Victron App To Monitor Solar Energy Harvesting Data

Step 3: From Charge Controller To House Batteries

Connecting Solar Charge Controller To Bus Bars - Wiring Diagram
Connecting solar charge controller to bus bars (and 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.

In Our Case: Since our Victron solar charge controller has a max amp rating of 30 amp, we installed a 30amp Circuit Breaker in between our charge controller and batteries.

Our 30amp Circuit Breaker

30amp Circuit Breaker

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.

Camper Van Solar System - Bus Bars
Positive & Negative Bus Bars

And voilà!

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.

Solar System Installation Diagram - Overview
Solar Panel to Camper Van Electrical System Installation Guide

To get more detail on our solar panel installation and with clickable pictures download our FREE Camper Van Electrical Installation PDF.

This post is PART 7 of our 7-part DIY Solar Build Series. Check below to view the entire series.

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