How to Choose the Right Solar Panels for Overlanding
"Overlanding" is becoming an increasingly popular way to travel and explore the world. For the uninitiated: overlanding is a style of long-term, off-grid, remote camping in which the journey is the goal rather than the destination. Some people spend months or even years overlanding - the "vanlife" movement is an excellent example of an overlanding community.
You need lots of things to be completely self-sufficient while overlanding: water, a sturdy vehicle, and airtight food storage - but a solar system is one of the most crucial components of an overland setup. Solar panels are the primary power source for overlanders, and your overland solar system must be reliable.
Why Use Solar Power for Overlanding
When you travel and live in your van, all your electricity comes from batteries, which need to be charged by something. You can plug into "shore power" at campsites or RV parking lots when you're close to civilization.
But when you spend extended periods away from civilization, you'll need to find another power source to keep your battery bank topped up.
Enter solar panels. Every off-grid, long-term van life setup relies on solar in some form or another. Yes, you can charge your batteries off the motor, but solar becomes your primary power source when you spend days parked in a single location without moving.
Photovoltaic panels (your "charge source") absorb energy from the sun and store it in battery banks. A van setup usually has two battery banks: the factory starter battery, which starts the engine and powers the vehicle, and the auxiliary “house” battery bank, which powers all the other systems like the lights and fridge.
Types of Solar Panels: Rigid Glass, Silicon, and Thin-Film
Once you've calculated your energy needs, you'll want to consider what type of solar panels best fit your setup. These days there are many different kinds of solar panels: rigid solar panels, flexible panels, and even portable panels. All have different outputs and various pros and cons.
We will focus on rigid glass, silicon, and thin-film solar panels, all of which have their own characteristics, advantages, and disadvantages. Let's delve into the details of each type:
Rigid Glass Solar Panels
Rigid glass solar panels, commonly called crystalline silicon panels, are the most widely used type of rigid panel on the market.
They are made from silicon wafers, usually mono-crystalline or polycrystalline, and encased in a tempered glass cover with an aluminum frame.
The solar cells in mono-crystalline panels are made with a single silicon crystal. The crystals are shaved into the perfect shape to fit into the cell; therefore, more cells can fit into a panel, and there is no wasted space between cells.
On the other hand, polycrystalline cells use multiple silicon cells melted together. The shape of the silicon cell is less perfect, meaning there are gaps between solar cells, and the overall panel is less efficient than a mono-crystalline panel. Polycrystalline solar panels are typically less expensive than mono-crystalline panels.
Pros:
Efficiency: Crystalline silicon panels, especially mono-crystalline variants, offer high-efficiency rates, making them capable of generating significant amounts of electricity in a smaller space.
Proven Technology: The technology behind crystalline silicon panels is mature and well-established, with decades of research, development, and manufacturing refinement.
Cons:
Weight and Rigidity: The rigid structure and the use of glass make these panels relatively heavy and inflexible, limiting their application to flat or slightly sloped surfaces.
Aesthetics: The appearance of glass panels on your vehicle rooftops might not be aesthetically pleasing, especially if you have a smaller overlanding rig.
Installation Complexity: Mounting rigid glass panels may require a more robust mounting system due to their weight and structural requirements.
Manufacturing Energy: The production of rigid glass solar panels requires more energy than other solar panel technologies.
Thin-Film Solar Panels
Thin-film panels are made by depositing thin layers of photovoltaic material onto a substrate like glass, metal, or plastic. They have a flexible and lightweight design, allowing for more versatile installation options. XPLOR's Flex Si solar series modules are high-quality thin film panels.
Pros:
Versatility: Thin-film panels are flexible, lightweight, and can be applied to various surfaces, including curved and irregular shapes such as a tear-drop camper trailer or a curved vehicle roof.
Aesthetically Pleasing: Due to their low profile and ability to form to different shapes, thin film solar panels can often be installed to be nearly undetected, so they won't take away from the design lines of your vehicle. This is also helpful for people who want a setup that is more stealth-looking.
Cons:
Lower Efficiency: Thin-film panels generally have lower efficiency rates than crystalline panels, requiring more space to produce the same amount of electricity.
Space Requirement: Due to their lower efficiency, larger installation areas may be needed to achieve the desired energy output.
Thin-Film Solar Panels with CIGS Technology:
Thin-film solar panels manufactured with Copper-Indium-Gallium-Selenide (CIGS) technology are a specific type of thin-film solar technology.
XPLOR's Flex+ solar series is manufactured with CIGS technology and is the most rugged solar panel for overlanding on the market.
CIGS panels are made by depositing thin layers of copper, indium, gallium, and selenium onto a substrate, often glass or flexible materials. The CIGS material absorbs a wide spectrum of light, making them extremely efficient in converting sunlight into electricity.
These panels are flexible, strong, and lightweight, allowing for unconventional installation methods.
Pros:
Efficiency: CIGS thin-film panels have shown significant improvements in efficiency over traditional thin-film technologies, often rivaling polycrystalline panels and performing better than other thin-film variants.
Flexibility: CIGS panels can be manufactured on flexible substrates, allowing them to be integrated into various applications, including curved surfaces.
Higher Temperatures: CIGS panels have a higher temperature tolerance than crystalline silicon panels, making them more efficient in hot environments.
Low-Light Performance: CIGS panels perform better in low-light conditions, making them suitable for use under diffused sunlight and overcast conditions.
Aesthetics: Their flexibility and versatility make them suitable for integration into rooftops or various overlanding rigs without compromising the vehicle's visual appeal.
Sustainability: The manufacturing process for CIGS solar panels is more environmentally friendly than other types of panels.
Cons:
Manufacturing Complexity: The manufacturing process for CIGS panels is more complex than traditional crystalline panels, which can contribute to slightly higher production costs.
Cost: Due to the higher production costs, CIGS flexible solar panels are more expensive than traditional glass or other flexible panels.
Portable Solar Panels
Portable solar panels are lightweight, compact, and designed for easy transport. They often come with foldable designs, making them convenient for storage and transport in vehicles. Always ensure your portable panels can be easily connected to your overland vehicle's existing solar system or battery setup and that the wattage output is compatible with your battery setup.
Here are a few reasons you might want to add portable solar panels to your overlanding setup:
Mobility: Portable solar panels are designed for mobility, allowing you to set up a solar power system wherever you go, even in remote locations.
Supplementing Energy: While overland vehicles may have built-in solar systems, portable panels offer additional energy generation, especially if the vehicle is parked in a shaded area or needs extra power.
Scalability: Portable panels can be added to an existing solar setup to increase energy production, providing flexibility as your energy needs change.
Backup Charging: When paired with a portable power station to store electricity, portable panels can act as a backup power source in case your vehicle's solar system encounters issues
Customization: You can tailor your energy generation to your specific needs by deploying portable panels if you need to power additional equipment.
Factors to Consider Before Buying Solar Panels
Before choosing solar panels, make sure you have calculated your energy consumption, looked at the maximum power output of the panels, measured your available space, and considered panel weight. All overland solar systems are different due to the various needs of the overlander, vehicle type, and the primary environment they will be in.
Mounting Options
Most solar panels will be mounted on a roof rack. This provides the clearest view of the sky and allows for maximum output. A sturdy aluminum frame is recommended for rigid panels. If you have flexible panels, your options are a little more varied.
Many overland solar panel setups mix portable solar panel solutions and permanent, roof-mounted panels. Of course, you can get away with not having roof-mounted panels, but portable panels can become a pain to set up and take down all the time, and they generate no power when they're not set up.
Weather and Climate
Remember that the output rating you see on the panel refers to the panel's output under ideal conditions and direct sunlight. However, if you live or travel somewhere with less sun, you will see less power produced from your panels.
Even partially shaded panels output less power than panels in direct sunlight on a sunny day. How many sun hours do you average on the darkest month? Use that metric to calculate how much power you will likely get from your panels.
Another key factor to consider is the "temperature coefficient" of solar power. Solar panels work best on a sunny day, but they also lose some efficiency when that sun is accompanied by excessive heat. Generally, solar panels will begin to generate slightly less power once the temperature rises above 77°F.
Assessing Energy Requirements
So how exactly do you size your solar panels and determine how much energy you need? Let's take a quick look at the steps involved.
Calculate the Energy Consumption of Electronic Devices
Your daily energy usage is calculated in amp hours. Amp hours is the amount of current used times the number of hours used.
You can find the amount of current an appliance or system draws by checking the owner's manual, looking up specs online, or sometimes just looking at the device itself. You'll need to do this for all the 12V appliances you have (fridge, fans, etc.) and the 120V appliances (laptops, blenders, etc.)
Once you have the electrical current drawn by each, multiply that by the hours used to get the amp hours (there are online calculators that can do this for you).
Factor in Battery Capacity for Overnight Usage
Don't forget to think about overnight use. Daytime power is typically easy-peasy because the sun is out all day, constantly topping up your batteries as you draw from them.
If you leave things running overnight (the fridge, for example), you'll need to ensure your battery bank is large enough to store enough power to keep those systems running.
Think about what things you don't need to run overnight and try to turn them off if possible.
Selecting the Right Charge Controller
A charge controller regulates the amount of power added to the batteries at once to prevent the batteries from overcharging. Overcharging can lead to significant damage to your batteries.
Most 12V panels output up to 16 volts, but they only need around 14 volts to be fully charged. That's where a charge controller comes in.
PWM vs. MPPT charge controllers: Which One Suits Your Needs?
The two main types of charge controllers are PWM (Pulse Width Moderation) controllers and Maximum Power Point Tracking (MPPT) controllers.
MPPT converts any excess input from the panels into amperage, whereas PWM controllers "pull down" the voltage produced by the solar panels to match what the batteries can handle.
MPPT controllers are a newer technology that is able to harvest more power efficiently from the panels. However, that efficiency comes at a premium, and less expensive PWM controllers are usually fine for a smaller setup - especially in hot climates with lots of sun, where the extra power you get from MPPT controllers is not needed as much.
Batteries for Power Storage
The next part of your solar power system is the battery bank. There are several different types of batteries, and again, each comes with its pros and cons. Let's briefly discuss the various types and which might be best for your solar system.
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Lead acid batteries are the traditional and most commonly known type of auxiliary batteries. They've been around for a long time and are relatively inexpensive. They work by using lead plates immersed in an acid solution. They are quite robust but tend to be heavier, larger, and less efficient than newer battery technologies.
Lead acid batteries can't be discharged more than 50% without damaging the battery, so you have to plan your amp hours based on the knowledge that you can only use half if your battery capacity at a time.
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Gel batteries are a type of lead acid battery. The key difference is that the electrolyte (the acid solution) is mixed with a gelling agent to create a semi-solid substance. This design reduces the chance of acid leakage and makes the battery more suitable for off-road use. They're relatively maintenance-free and can be mounted in various positions, making them suitable for an overland solar setup on a vehicle that will experience rough terrain.
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AGM batteries are another variant of lead-acid batteries. Here, the electrolyte is absorbed by a fiberglass mat, which is placed between the lead plates. This design reduces the risk of acid leakage, improves battery efficiency, and allows for faster charging and discharging. AGM batteries are also more durable and can handle deeper discharges compared to traditional lead acid batteries.
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Lithium-ion batteries are a newer and more advanced technology. They use lithium ions to store and produce power. Lithium batteries are much lighter and smaller compared to lead acid batteries, which makes them great for overlanding where space and weight are important.
They also have a higher energy density, meaning they can store more power in a smaller package. A lithium-ion battery offers better efficiency and a longer lifespan compared to lead-acid batteries.
Wattage, Voltage, and Amp Hours: What Do They Mean for Overlanders?
Before you install solar power into your overland vehicle, make sure you understand the difference between watts, volts, and amp hours.
Volts describe the "pressure" of electricity (how forcefully it flows through the wire), while amps (or current) describe the amount of electricity. You need to measure both to understand how much power you are generating.
Watts describes the amount of work being done by the electricity at a given moment. Watts are calculated by multiplying volts and amps. Watt hours are the amount of work done by 1 Watt over 1 hour. For example, a 100 Watt light bulb left on for 10 hours will consume 1,000 Wh (or 1 kWh) of energy.
Amp hours are a measurement of charge. One amp hour describes how many amps flow over a one-hour period. For example, a 150 Ah battery would expel 150 amps in one hour or 150 Ah.
Evaluating Solar Panel Brands and Manufacturers
The best way to figure out which solar panel brand is best for you is to talk to other overlanders and find out what they are using. Visit online forums and ask questions. You'll find that most people are very eager to talk about their solar setups and happy to share information.
There are many excellent blogs out there, run by overlanders who make a living sharing their knowledge with new people. You can often email these people or through the contact form on their website to ask questions.
And, of course, reading customer reviews and researching the reputation of various solar panel companies goes a long way.
What Solar Panel is Right for You?
Solar power is a must-have for anyone considering long-term camping or overlanding. It is a highly sustainable, efficient form of power that will increase your range and lower your carbon footprint.
While the up-front cost of a decent solar system can be pricey, it is worth it in the long run, especially if you will be living in your van or RV full-time or overlanding for extended periods of time.
Before purchasing and installing a solar system for your vehicle, make sure you have calculated your daily energy needs, measured your available space, considered the climate of where you will be overlanding, and have a basic understanding of watts, amps, volts, and charge controllers.
If you have questions about what XPLOR solar panel is best for your overlanding vehicle, please feel free to reach out to us via our contact form.
