Of all the different sections in a camper van electrical system, the most complicated part is the solar system. That is because this is the section that requires the most amount of calculations, correct product sizing, waterproofing considerations, and more. Unlike other areas of the electrical system, directly copying what you see in a solar diagram might not necessarily be appropriate for your needs.
Therefore, in this post we discuss the 9 most common solar installation mistakes we see in camper van conversions. This is an important post to read BEFORE building your solar system so that you can avoid many of the same errors we’ve seen with other camper vans.
If you’re ready, let’s get to it.
1. Not Enough Solar Power
One of the biggest mistakes van converters make when building a solar system is not installing a large enough solar system to adequately meet their energy demands. In other words, not enough WATTS.
Oftentimes, we see camper vans with only one or two 100W panels on their roofs. But in many cases, only having 100-200W of solar isn’t enough. This is especially true if you plan to travel outside the summer months or intend to use power-hungry electrical devices, like an induction cook top or water heater.
Solution: That’s why we recommend readers to use our solar calculator. When used in conjunction with our battery calculator, these services will help you to arrive at a solar wattage size that is suitable for your energy demands.
From the solar panels, to charge controller, to the batteries, and everything in-between, this eBook has you covered. 12+ pages of detailed diagrams, product recommendations, and links to additional resources.
2. Wrong Solar Wire Thickness (AWG)
One of the dangers about strictly copying a solar wiring diagram ‘product for product’ is that it potentially leads you to have undersized wires. This can be a serious fire hazard if a large solar array is pushing too much current (Amps) through too thin of a wire.
Solution: That’s why we recommend visitors to read our solar wire size guide. But read this only after you know how much solar watts you will install. Only then can we help recommend either 12 AWG, 10 AWG, or even 8 AWG wire for your solar system.
We love Ancor's 'marine grade' wires for solar installations. The insulation jackets are UV & salt water resistant (good for rooftop installations).
3. Wrong Solar Charge Controller Size
Just like with the wires, the size of the solar charge controller depends on how many watts your solar array can generate. The larger the wattage, the greater the Amp-rating the charge controller will need to be.
For example, Victron Energy sells charge controllers in the following sizes:
- 10A / 75V
- 20A / 100V
- 30A / 100V
- 50A / 100V
But how do you know which charge controller you need?
Solution: That’s why we recommend readers to read our solar charge controller size guide. Just be sure that you already know how many watts your solar array will have first.
4. Wrong Size Circuit Breakers
Circuit breakers are critical components that protect your solar wires from overheating and catching on fire. But installing just some random breaker isn’t good enough and may not necessarily make your van safer.
This circuit breaker protects the solar wire from overheating and is installed between the solar charge controller and the positive bus bar.
To calculate the correct circuit breaker amperage, you need to know what size solar wire you will be using. Once you know the wire gauge (AWG), you can determine your correct breaker size.
For more information how to do this, refer to our solar calculator. Once you input all the standard information relevant to your unique build, the calculator will recommend the correct sizes of all the various components you will need to build your solar system.
5. Not Using Marine Grade Solar Wires
For electrical wires inside a camper van, upgrading to high-quality ‘marine grade’ wires isn’t critical. But because a portion of the solar wires will be outside on the roof, and exposed to mother nature’s elements, we recommend going with marine grade cables.
What are “Marine Grade” wires? These are tinned pure copper wires that are encased in tough insulation that resists corrosion when exposed to UV light, salt water, oil, and more. The name “marine grade” means that these wires meet certain quality standards and are able to withstand the harsh open ocean environment.
Once you know what size solar wires you need, we recommend going with “Ancor” branded wires. These are the wires that we use in our own van and trust their quality.
6. Not Waterproofing The Solar Mounting Brackets
Surprisingly, we still come across some van conversions that do not do enough to waterproof the edges of the solar panel mounting brackets. Whether solar panels are screwed directly onto the roof or attached via a roof rack, there will still be some areas on the roof that water can penetrate through to the inside of the van.
That’s why we recommend doing an extremely thorough job in waterproofing the connection points to the roof. Because once you discover a water leak, there’s likely already too much water damage to fix quickly and easily.
When mounting the solar panels to the vehicle roof, we always recommend a combination of both Butyl Tape and Lap Sealant. This creates a two-layer protection barrier against water entry. For more information, read our solar panel mounting guide.
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7. Not Connecting Solar Panels In Parallel
One of the greatest benefits of wiring solar panels in series is it’s wiring simplicity. However, solar panels that are wired in parallel are more efficient at generating power when partially shaded. And when traveling in a van, the amount of time solar panels are spent partially shaded is longer than you might think.
However, due to the nature of solar wiring and safety, we recommend wiring panels in parallel ONLY IF you have two panels, and not more than two. This is because if you have more than two panels, you will need to install in-line fuses, which adds an additional layer of wiring complexity, cost, and risk.
Therefore, if you originally planned to install three 100W panels, consider getting two 150W panels. Or get two 200W panels instead of four 100W panels. This way, you can still have two solar panels and have them wired in parallel.
For more, read our series vs. parallel solar wiring post.
8. Not Using Rigid Solar Panels
This will probably get us hate mail, but we’re going to say it. We hate flexible solar panels and under virtually no van life situation would we ever consider using them. Compared to rigid solar panels, flexible panels are:
- More expensive per watt
- Less efficient at converting sunlight into power
- More prone to malfunctioning & breaking
- More prone to overheating
We understand the allure of flexible panels, such as requiring a less invasive installation process and having a thinner profile, which is better for stealth camping. But even after factoring in these benefits, flexible panels still aren’t worth the trouble. In our 4+ years on the road, we’ve already met a handful of van lifers who have already had to replace their broken flexible panels or who weren’t satisfied with their solar array’s lower power output.
Solution: Get rigid solar panels. Yes, they’re heavier and yes, they’re more visible. But having a steady and reliable power production solution is a critical part of any camper van’s build and not something to take risks with.
Download our FREE PDF to help build your van's electrical system; from batteries, to solar, to inverter, and more. 38+ pages of detailed diagrams, product recommendations, and links to additional resources.
9. Not Using The Newest & Most Efficient Solar Panels
As of this writing, the newest & most efficient solar panels are assembled with 9 bus bars connecting each of the solar cells. (Legacy panels only have 5 bus bars linking each cell.) What this means is that electricity can now flow more efficiently between the cells with less power loss. Also, the negative effects of micro-cracks that form in the solar cells over time have a reduced impact because of the existence of more bus bars.
Interested to learn more? Read our 9BB solar post.
We've spoken with BougeRV reps and came away impressed with their customer service. They also make great quality, highly efficient '9BB' solar panels. Consider installing a larger 200W panel instead of multiple smaller panels. But use our solar calculator first!
Solar panels assembled with 9 bus bars are called 9BB panels, and you can easily find them on Amazon. We recommend the 200W 9BB solar panels from BougeRV. Though this is a Chinese company, they provide high-quality panels and have dedicated English-speaking staff that attends to all US sales. We know this from experience and we’re impressed with BougeRV.
Enjoyed reading? For more useful build content, check out our van conversion guide.
Final Thoughts: Learn From Other’s Mistakes
While building a DIY solar system isn’t rocket science, you do need to be aware of a number of solar factors before starting the installation process. Staying on top of these issues not only ensures that you’ll have sufficient power to run all your electronics but also that your camper van remains safe from potential fire risks.
If you have any follow up questions, please don’t hesitate to send us an email.
Happy building!
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