How to Design and Install a Campervan Solar System – The Ultimate Guide 

Having a campervan solar system can help move you closer to the dream of being self-sustained and fully charged whenever you camp, vacation, or simply choose to live life “off the grid” for a while. And if you’ve never done any DIY work with solar panels, you might be apprehensive to dive in. But don’t worry, because Van Builder HQ, is here to help!

In today’s guide, we’re going to teach you how to design and install your very own campervan solar system, and even point you in the direction of some of the best solar panels for RV and campervan enthusiasts. So, let’s get started!

The benefits of having solar panels on your campervan

Before jumping into the primary benefits of adding solar panels to your campervan, it’s important to consider exactly what solar panels can and cannot do. Essentially, solar panels act as an additional power source to charge your batteries. In most campervans, sprinter vans, and Class B RVs, you’re going to be running power from the engine. This means that the engine’s alternator is not just providing power to the vehicle itself, but also diverting power to the “house” battery system for your van. In other words, you probably rely on your engine to power your lights, refrigerator, and any other electrical accessories you use. 

While your engine can do all of this, solar panels cannot. This is because you would need enormous panels to power everything in your van, even if you were only using lights. Most vans simply don’t have enough real estate to accommodate the panels needed to power your entire system. However, a campervan solar panel system can help provide power to your house battery system and work as an additional power source. In doing so, campervan solar panels help your electrical system run more efficiently and increase the life of your engine and house batteries. 

This is especially useful if you don’t plan on using your van for extended periods of time. For example, if you plan on keeping your van in storage or parked in your driveway for a few weeks or months, solar panels can provide a trickle charge, which ensures that your battery is “topped off” with power while it’s not in use. This means that you won’t have to go out and start your van’s engine every once in a while to avoid the battery being discharged; as long as the solar panels have access to light, they will passively keep the battery charged for you. 

Components of a campervan solar system 

Contrary to popular belief, solar systems are not all that complicated. They have a few essential components, and understanding how these components work can help you design and install your very own campervan solar system. In the sections below, you’ll learn more about how they work and how each component contributes to the operation of the entire system.

Solar panels 

The actual solar panels are the main components of your campervan solar system. They can come in various sizes, ranging from very small (50 to 100 watts) all the way up to very large (300 to 350 watts), and in some cases, even extra-large panels that go all the way up to 500 watts. 

When choosing solar panels, you’ll ideally want to use smaller panels and couple them together. Generally, it’s better to use more than one small panel because it ensures that you always have access to solar power. If you only have one big panel and you experience a technical problem, you’d have absolutely no solar power until it can be repaired. Alternatively, with many smaller panels, you can unplug and repair any that may be malfunctioning while still getting solar power from the rest. 

If you want to explore the main types of solar panels used in vans, Renogy.com is a great resource. That said, there are essentially two different kinds of solar panels for vans: monocrystalline and polycrystalline panels. These days, most people use monocrystalline solar panels, though you might be able to find polycrystalline options if that’s what you prefer. However, monocrystalline panels are considered more efficient because they’re made of pure silicon (which also makes them a little more expensive). 

Within these two categories, you also have a few different structures, namely rigid and flexible. As the name implies, a rigid panel is fixed in place on top of your campervan using an aluminum frame and glass top that are strong, resilient, and easy to clean. Alternatively, flexible panels are smaller, lighter, and can be adhered directly to the surface of your campervan. This may be preferable if you have a curved rooftop or if you simply want a really quick and easy installation. 

Choosing the right campervan solar panel

When choosing the right campervan solar panel for you, there are a few different factors you’ll want to consider. In addition to the applications mentioned above, you’ll need to think about the overall efficiency of your panels. One thing that can really reduce solar panel efficiency is heat. A rigid solar panel has space between the roof of your van and the panel, which allows airflow that can help keep the panels cool and efficient. Unfortunately, flexible designs adhere directly to the metal of your van, which can make them heat up much faster.

You also need to think about size. Tiny 10-watt panels will only be enough to keep your battery topped off while your van is not in use. And while you should try to get as much power and efficiency as possible from your van’s solar panels, you’ll need to remember that it’s mathematically impossible to run your entire system from the panels alone. There’s simply not enough space on an average-sized van to install enough solar panels. In fact, you would probably need the surface area of five vans to fit enough solar panels to power just one van. 

This means that size is vitally important. You’re essentially trying to cram as many panels onto your van’s roof as possible. This is because solar panels are not all that efficient by default. You’re really only reclaiming about 20-30% of the power that the panel is rated to produce. So if a panel is rated at 100 watts, it’s very unlikely that you would actually reclaim 100 watts from the panel, outside of extremely ideal circumstances (low temperature, direct sunlight, etc). This means that, if you’re sizing your system’s needs based on wattage, you’ll want to go back and recalculate to consider that you’ll only get a fraction of the total possible wattage a panel can provide. 

There are also factors outside of the actual panels you’ll want to think about before you make a purchase. For instance, if you want space on top of your van for a vent, air conditioner, or storage, you’ll need to plan around these elements. You may need to opt for one or two fewer panels or choose long, narrow panels that can be installed around your other rooftop components. You might see some very small differences (just one or two inches) between different panels available online, but when you’re working with such a small surface area, even just a few inches can determine whether or not your panels will fit. 

If you’re looking for specific brands to consider, ZampSolar.com provides some high-end options, though you will have to pay a bit more than most other providers on the market. On the other hand, Renogy.com has quality products that work well and won’t break the bank. 

Fixed vs. portable solar panels

For most people, fixed solar panels are the better option because you don’t have to worry about setting it up every time you need it. Once it’s installed, you can just set it and forget it. With portable solar panels, you’ll need to pull them out and set them up every time you need them. Storing and moving these panels around also increases the risk of cracking or damaging them. 

With portable solar panels, you’ll also need to find flat terrain, free of shade, that has access to direct sunlight. Since you’re only going to get about 5 hours of direct sunlight per day in any given location, this means that it can be pretty impractical to rely on portable panels regularly. In general, portable solar panels are best if you’re going to be in one location (like a campsite) for a few days or weeks at a time. They can also be good as a supplement to your fixed panels in certain situations.

How many solar panels are needed?

There’s no one right answer to this question, but you should try to have as many panels as you can comfortably fit on the roof of your van. If you’re just starting out, aim for 100 Watts per 100 Amp Hours of power in your battery system. This is just a general rule of thumb, but it’s a good start and an easy way to calculate your needs. 

And something that’s important to remember is that it’s generally best to install uniform panel sizes, regardless of how many you use. This is because, depending on how you wire your system, it may use a higher voltage or a higher current. If one panel has a higher amp potential, your system may or may not use it. But if you go with uniform panels that have the same outputs, you won’t have to worry about losing efficiency. 

Solar charge controller 

The second component of your campervan solar system is the charge controller. This is what takes the high voltage coming out of your solar panel and converts it to the voltage preferred for your battery. The type of battery you have — like a lead-acid battery, AGM, or lithium iron phosphate battery — will determine the unique charge profile and battery chemistry. The solar charge controller allows you to adjust the settings to the preferred charge profile and battery to maximize the power output. 

There are two different types of charge controllers: PWM and MPPT. A PWM (Pulse Width Modulation) controller is typically less expensive and less efficient. It’s a basic controller with no extra bells and whistles. However, since it’s been in use for years, the PWM is often the default controller that many people use. An MPPT (Maximum Power Point Tracking) controller is far more efficient, but it also costs more than PWM models. 

Fuse 

When it comes to dealing with the fuses of your solar system, you want to make safety a top priority. First, you’ll want to have an inline fuse on the positive line between the solar panels and the charge controller, as well as the positive line between the charge controller and the battery. You also want to have a dual or double pole breaker.

The double pole breaker is particularly important because, if you have a solar panel that fails or shorts out, it could backfeed on the negative line. The double pole breaker keeps the negative and positive lines separated so that this won’t happen. The breaker also makes it easier to turn the panels off to do maintenance or repairs. 

Wiring

You have to remember that there is no “off” switch on a solar panel; as long as it’s taking in light, it’s always putting out power. And in some cases, the voltage can get quite high. So, as a safety precaution, you should always make sure the terminals are covered before you try to do any wiring or maintenance. The simple solution is to put a piece of cardboard over the solar panel. This is the best way to turn it “off” by blocking access to light. 

When setting up the wires and cables for your solar system, you’ll want to use MC4 (male and female) connector cables. MC branch adaptors also ensure that you can group multiple solar panels together. Naturally, your specific configuration may vary a little based on what you want to do. You can wire your panels as series or parallel circuits (depending on your specs and preferences), and then those wires will go directly into the charge controller. Finally, you’ll have the wires coming out of your charge controller — with one as the negative or grounding wire for your system and the other as the positive lead coming out. 

Battery monitor 

A battery monitor essentially tells you how much power is coming in and going out of your battery. It calculates this data by using what’s known as a “shunt.” A shunt is a device that works on the negative side of the system. It basically reads all of the power going into the battery, as well as the power being taken from it. 

A simple battery monitor with a shunt just functions like a calculator. It can only look at all of the power going in and out of your system (not just solar). However, you can opt for a more complex system that can tell you how much time until the battery is fully charged, how much solar is contributing to your battery power, and so on. Even if you just have a simple battery monitor and shunt, you may be able to see specific solar readings with an MPPT charge controller that is Bluetooth enabled. This way, you can connect your controller to your smartphone to see how much power is coming in from your solar panels.

How much does it cost to install solar panels on your van? 

The installation cost will vary substantially based on who does the work. If you want to do a DIY install, you can probably get it done whenever you have a free weekend, and this will essentially eliminate the labor costs. However, it’s still not easy to calculate professional labor costs, as there are a lot of different factors at play. For example, you may just need the panels added, or you may need wiring work done, too. Additionally, the cost could depend on the design of the system. Is it custom-made or prebuilt? In short, you may want to reach out to professionals to ask for a quote, as there are just too many variables to come up with a ballpark figure.

How to install a campervan solar system 

Once you’ve acquired the basic components of your system, chosen the right solar panels (including size, shape, and wattage), found the right charger controller, gotten the right cables and dual pole breaker for your system, and designed the battery bank to withstand the incoming power, you’re ready to start your install. 

Mount and wire the solar panels 

The first step is mounting and wiring the solar panels together. You can either mount the panels to the roof rack or you can bolt them directly to the roof of your van. It is usually better to mount them to the roof rack, even if you don’t plan on using the roof rack for its intended purpose. Why? Because you never know if and when you’ll need a roof rack for storage later on. Plus, most roof racks are standardized in width and length, making it easy to accommodate and mount solar panels with ease. You can also keep the wires against the rack with zip ties, making it easier to keep track of all of your cables and keep them safe from damage. 

Wire your battery

Once the panels have been mounted, you’ll need to wire them to the batteries using cables from the solar panel kit or comparable cables that you’ve purchased separately. 

Fuse the solar panels 

Once the wiring is done, you’ll need to fuse the solar panels. Remember to use an inline fuse from the solar panel to the charge controller and from the charge controller to the house battery. 

Wire solar panels to charge controller 

Then, you’ll want to wire the solar panels to the charge controller, ensuring that you’ve chosen the appropriate charging profile for the house battery. 

Connect charge controller to battery

Lastly, you’ll need to connect your charge controller to the house battery. Make sure that you have properly fused this connection and the positive & negative wires coming for the charge controller to the house battery are sufficiently sized to safely carry the charging current to the house battery.

FAQs 

How much solar power do you need for your van? 

There’s no fixed amount of solar power that you’ll need for your van. But generally, the more the better. It is good to aim for 100 – 200 Watts per 100 Amp Hours. This will help ensure that your solar system is working as a substantial source of additional power.

Which type of solar panel is best for a campervan?

Monocrystalline solar panels are generally the most efficient and cost-effective solar panels for campervans. However, most monocrystalline solar panels just absorb light on the top side. If you want to get even more power from your system, you might consider bifacial monocrystalline panels that absorb light on both sides. This will give you extra power from sunlight that reflects off the surface of your van. 

What solar panel size do you need?

There is no perfect size solar panel for vans. It all comes down to how much space you have. Most vans are going to be about 58 to 60 inches wide, so if you plan on using the entirety of your roof for solar panels, you can use these figures to begin calculating the best shapes and sizes to fit your needs. 

How to attach solar panels to the vehicle roof?

You can either mount your solar panels to your van’s roof rack or bolt them directly to the roof of your van. If you bought your solar panels as part of a kit, they will often come with specific brackets, instructions and tools to help you mount them correctly.