how to install solar panels on an RV

How to Install Solar Panels on an RV: Beginner’s Guide

If you like to travel off the beaten path to enjoy quiet, untouched nature, you will not have frequent access to shore power at conventional RV campgrounds.

To be able to power your electronics while keeping your house battery charged, having a sufficiently large solar charging system is a must to stay self-sufficient with regards to energy consumption.

Learn how to install solar panels on an RV with this beginner friendly step by step guide, so that you will be off-grid ready for your next adventure. You will also find handy tips and answers to common questions that will make your DIY project more manageable. 

Portable vs Permanent Built-In Solar Systems

how to install solar panels on an RV
Photo: Voyagerix / Getty Images

Before we proceed with how to install solar panels on an RV, it’s important to take note of two different types of solar charging systems for RV, since their scope and complexity would be very different, and thus their installation process would also be worlds apart in terms of difficulty level.

Depending on the size of your system, you might or might not require professional help when installing solar panels on an RV.

Large Built-in Solar Systems

Unlike small solar battery chargers that are only powerful enough to charge an RV’s house battery, a large RV equipped with many power hungry appliances would require larger solar panel systems that are permanently built into the RV.

In addition to charging your RV battery, these systems can generate more power to serve as a primary power source and power up the electronics in your rig, including heaters, dehumidifiers, oven and vacuum cleaner or power RV air conditioners.

These systems come complete with solar panels, charge controllers and complicated wirings. They are quite sophisticated and thus not for the novice; you would likely require professional installation. 

Portable Solar Panels

Meanwhile, owners of smaller rigs with average power consumption might find portable solar panels sufficient and straightforward in terms of installation and usage. These all-in-one kits usually include everything you need for installation. 

Although not as powerful as built-in systems, these portable systems are larger in size than solar battery chargers and can still meet basic electrical needs of small to medium sized RVs, including powering the lights, charging personal devices and powering small electronics like coffee maker, electric kettle and WiFi router.

Depending on their wattage rating, you might be able to find a portable system like this that is powerful enough to operate more power-demanding appliances like a 12 volt fridge, a portable air conditioner or a portable dehumidifier. 

Easy installation also means that these portable solar panels can easily be uninstalled. There are even kits that are so lightweight you can carry around anywhere and designed to be strapped to a backpack for flexible camping applications.

Wiring Your Solar System: Parallel vs Series 

One absolutely crucial thing to decide before learning how to install solar panels on an RV is how you want to wire your RV solar panels. This depends on your house battery and power needs.

How the panels are wired together will determine the amperage output and the voltage of your system, how much power output you would get if a part of your system is in the shade, the type of wires you need and the type of charge controller required. 

In series

In essence, you connect the panels together to create one big panel, then connect this big panel to the charge controller. This setup is for when you need to double the voltage of the whole system while leaving the total amperage unchanged, which equals the amperage of a single panel. 

The major downside is that the power output of the whole system will be limited by the panel with the lowest output. This means if one panel is in the shade, all of the other panels will perform the same. 

Another downside is that while a series connection doubles the voltage, charge controllers are limited by voltage, so such a setup will require a higher voltage and thus more expensive charge controller.

In parallel

In this setup, each panel is wired into the charge controller separately, so you’re not creating one big panel but allowing each panel to operate on its own. This means if one panel is in the shade, the remaining panels will still achieve max power output.

This type of connection doubles the amperage and leaves the voltage unchanged. Higher amperage means that such a system will require higher gauge wiring, which are more bulky and more expensive. 

Series + parallel

If you want to create the most powerful solar system possible while avoiding the shortcomings of both a series connection and a parallel connection, a series-parallel setup would give you the best of both worlds.

Essentially, you have multiple series that you wire in parallel, thus you can achieve double the amperage as well as double the voltage, while limiting the size of your charge controller and using low gauge wires instead of the expensive high gauge wires. 

How to Install Solar Panels on an RV: A Step by Step Guide

General Safety Guidelines

Let’s learn the steps on how to install solar panels on an RV, but safety first:

  • Don’t sit or step on your panels
  • Only proceed with installation in good dry weather conditions
  • To prevent your panels becoming charged during installation, during the whole process, try to keep the panels covered with a cloth or keep them in the boxes that they came in
  • Once the panel is exposed to light, they will become charged, so avoid touching electrically active components, such as terminals.

Step 1: Mount Solar Panels on The Roof

  • Note: Rigid panels must be screwed onto the studs on your roof, while flexible solar panels for RV might be mounted with adhesive. You can also use both screws and adhesive for a more secure installation in case you often travel on rough terrains.
  • Lay out the panels on the roof to make sure everything fits and mark the locations with color tapes. Avoid locations in which an air conditioner, vent, or satellite dish might cast shade over the panels.
  • Attach the mounting hardware included in your solar kit to the solar panels frame. 
  • Put the panels in the marked positions and mark where you need to drill holes. Just like drilling holes on drywalls, you need to hit the studs on your roof for the most secure mounting. The studs are usually visible with a 2 to 3 inches wide gray line going width wise on your roof.
  • Drill small pilot holes into the studs. Fill the holes with a little dab of sealant to create a water-tight seal. Note that your roof membrane material will determine the type of adhesive required. If you’re not sure which type you need, check with your RV manufacturer first. 
  • Screw the panels in and remember to aim for the frame, not the panel itself to avoid accidentally shooting a stray screw into your panel. 
  • Tips: You might want to add an extra level of protection for a more secure installation by lining the bottom edges of each panel with butyl tape or where the panels touch the roof surface.
  • You’re basically done here. But you might want to add extra weatherproofing capability to the setup by applying a generous coat of protective sealant on top and around the mounting brackets to seal everything off.

Step 2: Wire The Solar Panels

  • In series: To wire solar panels in series, connect the positive terminal on the first panel to the negative terminal on the next, and so on. The remaining positive and negative wires on the ends of the array will then be connected to the charge controller.
  • In parallel: To wire solar panels in parallel, connect all of the positive terminals on each panel together and then do the same for the negative terminals. Connect the remaining positive terminals of the first panel in the array to the positive terminal of the charge controller using high gauge wire, then do the same for the last panel in the array separately. Then do the same for the negative terminals, also connect the first panel and last panel to the charger controller separately. 
  • In series + parallel: To make wiring simpler, think of a series-parallel setup as having multiple series that you wire in parallel. For instance, if you have four panels, you will want to wire two panels in series to form two duos first, then wire these two duos in parallel. That is connect the remaining positive terminal of one duo to the remaining positive terminal of the other, and do the same for the negative terminals. 
installing solar panels on an rv
Photo: Photosbyjam / Getty Images

Step 3: Run The Wirings

Now that the panels are fixed on the roof, you need to run the power cable from the solar panels down into the RV to the charge controller. There are a few options as run the wiring:

  • The most simple and thus most common method is to run the cable through the existing refrigerator vent. This way you won’t have to drill extra holes in your RV.
  • You will need to install the charge controller near the battery compartment. In case your refrigerator vent is located too far away from the battery compartment or located in a slide out, the best solution is to run the power cable through or beside the plumbing pipe.
  • If desired, you can always drill a hole where you need it. 
  • Tips: Try to drill near a cabinet or interior wall so you can hide the wire from sight. 
  • Tips: Remember to apply a generous amount of sealant around any holes you drill or use a weatherproof entry port.

Step 4: Connect The Charge Controlled

  • In this step, check the manual of your solar kit again. Some kits require that you connect the charge controller to the solar panel first, then connect the charge controller to the house battery. Meanwhile, some others recommend connecting the charge controller to the battery first.
  • In any case, mount the charge controller to the wall as close to your batteries as possible to minimize line loss, but away from heat and corrosive battery gasses. 
  • If needed, use a multimeter or voltmeter to test your wire polarity and mark them.
  • Then connect the charge controller with the power cables that you previously ran from the solar panels to inside the RV. Make the connections to your house battery or to the panels first depending on what the solar kit recommends.

Step 5: Connect The Inverter

The last step of how to install solar panels on an RV is optional. You only need to connect the inverter to convert your solar system’s DC power into residential AC power in case you need to use AC appliances like your microwave. 

  • Your inverter should be mounted near the batteries, again away from heat and corrosive battery gasses. 
  • Follow the instructions of your inverter.
  • Connect your inverter to your RV electrical system. Remember to connect the negative terminal of your inverter to the negative terminal of your house battery first, then the positive.

RV Solar System FAQs

How much does it cost to install solar panels on an RV?

One single solar panel typically costs anywhere between $50 and $300, depending on the size, efficiency and construction quality of the panel. Meanwhile, most solar panels for RVs offer between 100 and 400 watts of power per a single panel, so how many panels you will need depends on how large your RV is, how many electronic appliances are onboard, and how many people are sharing them, which decides your average daily energy demand. 

An average small sized RV consumes about 120 watts to 200 watts of power. As a reference, you can generally expect to spend from $600 for the simplest solar panel set up for camper for small rigs with minimal power consumption all the way to $2,000 for a larger RV solar panels installation to meet higher power demand. 

How long do RV solar panels last?

The best selling RV solar panels on the market can come with a 10 years, 15 years or 20 years warranty, and these solidly constructed units can really last up to 20 years if handled properly. That said, the cheaper options on the market might not last as long, and might malfunction before the 10 years mark. 

How many 100W solar panels do I need to charge a 12 volt RV battery?

This depends on many factors, including the efficiency of your RV solar charging system, how much sunlight you typically get daily and the capacity of your RV battery. 

The capacity of your RV battery is measured by its Ampere Hour, which you can find on its nameplate. For instance, your 12 volt house battery is rated for 100AH, that is it can supply 100 amp-hour of power per day based on the standard 20 hours of available use. Divide 100 amp-hour by 20 hours, we get the amp rating of the battery, which is 5 amps.

You need to charge this battery at 12 volts and 5 amps, which means you need at least 12 volts x 5 amps = 60 watts worth of solar panels to properly charge this battery. The rule is to always go up to provide some safety cushion, as there might be times when some appliance is drawing power from the battery while you’re charging it, so you should get at least one 100W solar panel.

What will a 100W solar panel run?

A single 100 Watt solar panel can power several small devices, including LED lights, ceiling fans, cell phones and laptops, wifi router and other electronics with low power draw. 

How many solar panels do I need to run my RV fridge?

You will need to calculate your fridge’s daily power consumption, that is the number of amps it draws per hour. You can find this information on the nameplate ratings, which are typically somewhere on the inside of the refrigerator.  

On the nameplate ratings you will see the unit’s voltage and current demands. Most portable 12 volt RV refrigerators on the current market typically consume between 1 amp and 6 amps an hour when running, with 2.5 amps being the market average. For example, let’s say your fridge lists 120 volts and 5 amps. 

You will then multiply these two numbers to calculate your fridge’s power demand: 120 volts x 5 amps = 600 watts of power per hour.

A fridge is something you will need to keep powered all day all the time. Also consider the fact that 1) there will be days when there’s very little sunlight, 2) your solar system won’t be 100 percent efficient, or there’s always loss of energy produced somewhere, and 3) you would most likely need to power some other appliance at the same time.

Therefore, you would need a solar system capable of at least 600 watts, but remember to add a 20 percent safety cushion, so the minimum requirement would be 800 watts. 

Can I directly connect an electronic device to my solar charging system?

Always make sure you consult your owner’s manual first, but generally, in most cases you can, given that your RV solar system installation kit includes USB ports that allow you to connect it to devices like mobile phones and laptops for direct charging. 

Are all solar panels the same?

There are three types of solar panels, which differ in terms of power output. Their size and construction also allows for different setup with regards to installation:

Monocrystalline panels: This is the most advanced type and is capable of producing the highest power output. While the other two types of solar panels typically only produce power during about 5 to 6 hours of peak sun each day, monocrystalline panels even work in weak sunlight. This is thanks to the fact that each panel is made from one large single silicon crystal, hence the name “mono”. Monocrystalline solar panels are understandably the most expensive. The only downside is that these panels are quite bulky.

Polycrystalline panels: Instead of being made from a single silicon crystal like the monocrystalline type, polycrystalline panels are made from multiple silicon blocks. This construction allows them to produce less power than monocrystalline solar panels. That said, they are sufficient for most average camping requirements and they are more affordable. Another reason that makes them more common than monocrystalline systems is that these panels also take up less space on the roof, which allows for more flexible setups. 

Amorphous panels: These thin-film panels are made from silicon spread on a large bed. This construction makes them flexible and thus gives you a bit more options in terms of installation on curved roofs, although this is undermined by the fact that these panels are about three times larger than the other two types. This type of solar panels are still widely used though, since they are the cheapest.

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