Having a source of electrical power when you are off the grid can really elevate your backcountry game. A portable solar system can provide electricity for your adventures for extended periods of time by collecting, storing, and using solar-generated energy.
This can allow you to power and recharge cameras, computers, lights, heaters, and small electronic appliances, including small heaters and portable refrigerators.
Here, we will provide an introduction to overland solar systems, exploring the different types and their uses, and offering some basic guidance for setting up your own system.
What is an overland solar system?
Overlanding, by definition, is self-supported adventure travel, and electrical power is often part of that equation.
At its simplest, you can use the same electronics devices such as flashlights and lanterns that you’d use for car camping or backpacking. But one of the advantages of exploring in a vehicle is that you can extend your ability to power electronics.
This means powering a greater variety of devices, including built-in lighting, water pumps for sinks and showers, and portable fridge freezers. It also means being able to potentially power devices indefinitely, using charging sources — with solar power being a major one.
In a separate article, I provided a general introduction to overland electrical systems. In this article, I’ll focus specifically on systems that use solar panels as a charging source.
While in the past, most overlanding enthusiasts relied on their vehicle’s engine to charge auxiliary batteries, recent advances in photovoltaic (aka solar) technology have spurred widespread adoption of solar among overlanders, RVers, and conversion van enthusiasts.
At its essence, a solar system involves three components:
- Solar panels to gather and convert sunlight into electricity
- Batteries that store the electrical energy in an electrochemical substance
- A means to draw from the battery to power lights, fridges, water pumps, laptops, and other devices.
Beyond those basic functions, solar systems used for vehicle-based exploration can take a number of different forms. We’ll give an overview of the two common types of systems in the next section.
Types of Overland Solar Systems
Broadly speaking, there are two types of solar systems used in overlanding vehicles and trailers: “built-in” systems and portable solar systems (commonly referred to as “portable solar generators”). I’ll go into both of these types of systems in greater depth below, but first I’ll give a quick overview of how I distinguish them.
Built-in solar systems have been around the longest and are the types of systems installed into commercially built RVs and camper trailers. They are also the DIY systems installed by RVers, conversion van owners, and overlanding enthusiasts. In these systems, the various components–solar panels, batteries, charge controllers, inverters, etc – are purchased separately and hard wired together in the vehicle or trailer.
Portable solar generators center around portable power stations where many of the components mentioned above are integrated into a pre-built box. Manufactured by companies such as Goal Zero, Jackery, Bluetti, Suaoki, and Anker, portable power stations greatly simplify the processes of setting up a solar system. These boxes include the battery, charge controller, and inverter, so all you need to do is get a solar panel that’s compatible with the station.
Next, we’ll take a deeper dive into each type of system and provide some general guidance on setting up a system that suits your needs. There will be some duplication of information between the sections on each type of system, as many of the concepts are relevant for both.
Portable Solar Generators
We’ll talk about portable solar generators first, as they are the most straightforward and are the best choice for many people.
In recent times, a whole industry has emerged to take the pain out of building an overland solar system. A number of companies produce relatively turn-key solutions for storing and using solar energy off the grid. For many people, these are replacing other options, such as dual battery systems, built-in DIY solar systems, and gas-powered generators.
If you are just looking for a quick recommendation, here is a versatile, quality option from Jackery for a overland solar system that will fit most people’s needs (through charging in your vehicle and/or the panel, you could run a small overlanding fridge on long trips):
Jackery Explorer 500 Portable Power Station
Jackery SolarSaga 60W Solar Panel
It’s worth noting that you don’t absolutely need a power station to use solar panels. Many of the newer portable panels now have USB plugs so you can plug electronic devices directly into them. However, if you are planning to spend any serious amount of time off the grid, having a power station for longer-term storage can be a real game-changer.
Below, we’ll look in more depth at the two components of a solar generator: solars panel and power station.
Portable Solar Panels
The panels, also known as photovoltaic panels, capture energy from sunlight and convert it into electricity. Portable solar panels have gotten much lighter, more efficient, and easier to store and carry in recent times. Newer panels also come with outputs for USBs and other types of power cords that allow you to plug electronics directly into a panel and power both AC an DC devices.
The power output of solar panels is rated according to the amount of direct current (DC) energy it generates per hour, measured in watts, under optimal conditions. A popular size of portable solar panel used for RVing and overlanding generates 100 watts. In a sunny place like Southern California, a 100-watt panel might produce 450 watt-hours of power on average, while it might only produce 280 watt-hours per day in a cloudier locale such as the U.S. Midwest.
Portable Power Stations
If you aren’t going to use all of the energy during the day, why not store the power for later? That’s where the power stations come in. Portable solar power stations center around a rechargeable lithium-ion battery that stores and then distributes the energy collected by the solar panel.
These can also typically be charged by plugging them into a home wall socket or by your vehicle’s electrical system. You can charge the power station before your trip, then recharge it while you’re driving or using your solar panel when you’re in camp.
Beyond the battery, turnkey solar power stations incorporate two devices: a solar charge controller and an inverter. The controller (also known as a regulator) manages the voltage and/or current to keep the battery from overcharging. The inverter converts the direct current (DC) coming out of the solar cell into alternating current (AC), which is the kind that comes out of your wall sockets at home.
This allows you to use electrical devices designed for AC power. We recommend you look for power stations that produce “pure sine wave” AC, as this form of current is what most AC power devices are designed to operate with.
The most important characteristic of solar power stations is their storage capacity, which is rated in watt-hours. A 500-watt-hour power station can deliver somewhere in the range of 500-watt-hours of energy on a single charge. We’ll get into more about what you might be able to power with that amount of energy below. But to give you a sense, a fully charged 500-watt power station could power a 60-watt portable refrigerator for around 35 hours on a single charge.
Often, manufacturers will also provide the charging times for power stations, which vary depending on whether you are charging it from a home wall plug, your car’s electrical system, or a solar panel. It may be stating the obvious, but larger-capacity batteries take longer to charge than smaller ones.
Built-In Overland Solar Systems
At some point, you may decide that you’ve outgrown your pre-built portable power station, or you may want to jump straight to installing a built-in system. Built-in solar systems for overlanding are typically larger capacity than the portable systems we discussed above.
They can range in complexity, from lightweight systems built into an off-road vehicle to large systems with multiple solar panels and batteries installed in overlanding trailers and conversion vans.
A simple built in solar system will include a few basic components:
As backcountry adventure enthusiasts, we’re lucky to live in the age of solar power. There are numerous small, lightweight panels on the market nowadays, from portable panels that can be easily folded up and stowed in your vehicle to panels with hard frames that can be mounted on the top of a vehicle or even a roof-top tent.
Battery technology has also come a long way in recent years with newer lead acid technologies emerging as well as lithium-ion batteries. We went through a pretty in-depth dive in our article on overland electronics, so we won’t duplicate it here.
Solar Charge Controller
Solar charge controllers prevent the solar panel from overcharging batteries and prevent the batteries from losing energy through the panels when the sun goes down.
An inverter is a device that modulates the power produced by the battery (DC) so that it can be used for a variety of applications (AC or DC). Inverters typically serve as the outlet that you plug various electronic devices into, whether it’s house lights, a portable fridge, radios, or personal electronic devices such as smartphones and laptops.
Wire & Fuses
Your system will need wiring to connect the solar panels, battery, and inverter together into an integrated system. In some cases, these wires and connectors will come with the devices. You’ll also need fuses and possible other safety devices to protect the system in the case of power surges.
One of the nice things about installing a built-in system is that you can install control switches/dials to conveniently turn things on and off or adjust them. For instance, instead of having to unpack a headlamp or lantern, you can just flip on a built-in light. This allows the battery to be stowed away, out of the way, but still be accessed and controlled via the dials and switches.
Hybrid Solar Systems
I just want to drop a quick note here to say that, while I’m covering built-in and portable systems as separate entities here, they aren’t necessarily mutually exclusive. It’s possible to have a built-in battery that’s hard-wired to various devices and power it with a portable solar panel that gets stowed away when on the road. Conversely, you could have a portable power station and power it with a permanently fixed solar panel.
Choosing an Overland Solar System
At first blush, choosing an overland solar system seems like a daunting task. Below, I’ll offer some guidance to help make the process easier.
Do you even need solar power?
If you will only camp for two or three days at a time and/or only need to power small electrical devices, you may not need solar panels.
I have a portable power bank that easily gets my family through several days of camping, keeping smartphones, lights, radios and even a laptop charged. I charge it at home before trips and can recharge it while driving from my engine. While I have a folding solar panel that I can use with it, I rarely need it on short trips.
Reasons you might need a solar system:
- You plan to be off the grid for long periods of time with limited opportunity to recharge from your vehicle engine.
- You plan to power larger devices such as fridges or water pumps that require consistent and/or significant electrical power (see below for more on this).
What devices will you power?
Among the first things you’ll want to figure out is to consider how you plan to use the system. The chart below will give you an idea of roughly how long you might expect fully charged portable power stations of various capacities to power different devices. Batteries of similar capacity in built-in systems would offer similar run times.
To determine how long your charged battery could power a larger device, like an overlanding fridge, multiply the capacity of your battery by 0.85 and then divide that by the power required by your device.
Power station capacity x 0.85/device power requirement
The 0.85 multiplier reflects the fact that no system is completely efficient and some power will be lost as energy is transferred through the system to your devices.
Oftentimes, the manufacture of a device may give energy usage in amps and not watts. To convert amps to watts, so you are comparing apples to apples (watts to watts), the formula is watts = amps x volts. So for a 12-volt device that draws 10 amps per hour, you get watts = 12 x 10, which gives you an energy usage of 120 watts per hour.
Let’s say you have a portable refrigerator such as a Dometic, ARB, or Engel fridge, that requires 12 watts of electricity per day (the actual power draw will depend on your temperature settings, outside temperature, and other factors). Using the equation above, a 500 watt-hour battery could power the fridge for around 35 hours on a single charge.
Of course, if you have opportunities to recharge the power station with your vehicle or solar panel, you can run devices for longer, which is something we’ll get into in the next section.
How long will you use and recharge the system?
Once you know what you plan to power, you’ll need to consider how long and how often you’ll be using your overland solar setup. If you will only use it for weekend camping trips, you could most likely go with a lower capacity system than if you are prepping for a months-long overland trip.
Also, consider what opportunities you will have to recharge. If you will be driving frequently for long distances during your trip, you can recharge your batteries from your vehicle. If you plan to set up camp for long periods of time, you can use your solar panel to charge the batteries while in camp.
On the other hand, when traveling in an area where it’s cloudy and raining or snowing a lot, your opportunities to recharge with solar panels may be limited (also, low temperatures will impact your battery performance).
The manufacturer of your batteries (whether it’s a portable or built-in system) will provide information on how long it takes a unit to recharge, which will likely vary depending on whether you are plugged into an outlet in your house, your car, or using your solar panel. For instance, a 500-watt-hour battery might take 7-8 hours to fully charge when plugged into a wall outlet and 8-9 hours when plugged into a solar panel.
One thing to consider is that you can use your batteries to power devices while you are charging your batteries with a solar panel during the day. So you would only need to use the power station alone to power devices overnight when the sun is down.
Every situation is different but, generally speaking, if you plan to use less power, take shorter trips, or have frequent opportunities to recharge, a smaller system will suffice. If you will use more power, are going on longer trips, and/or have fewer opportunities to recharge, a larger system might be warranted.
If you want to make sure you have enough power for your needs and have the cargo capacity, err on the side of purchasing a larger system. A larger capacity system can capture energy from the sun more quickly, has greater storage capacity, can power a wider range of devices, and will require recharging less frequently.
This could be very appealing to people with heavier energy requirements and/or on longer trips. The trade-off is the higher cost of the system, greater weight, and the cargo space it takes up.
Portable solar system vs. Built-in solar system
Once you’ve concluded you need a solar system, you have to decide between one of the two types described above: a portable or built-in system (or some combination of both).
So how to decide between these two types of systems? The primary trade off with these types of systems is charging and storage capacity vs cost, especially when you get into building larger systems with more capacity. Another big difference is the level of research and technical knowledge it takes to set up the system.
Put simply, built-in systems tend to be less expensive than prebuilt portable systems per their power storing and generating capacity, but they are more complicated and time consuming to set up (and mistakes can add to the cost).
Here are a few things to consider:
- If you will mostly camp off grid for no more than a few days at a time and/or power only a few small devices, a portable solar system (or no solar system at all) may be the best choice. Building a smaller system from scratch may cost nearly as much as buying a small pre-built system.
- If you don’t have time or mechanical inclination to build a system from scratch and don’t want to pay someone to do it for you, a canned portable system may be your best choice.
- If you are planning to travel for long periods of time off-grid and/or want to power devices such as portable fridge freezers and water pumps, a larger built-in system may be more cost effective per unit of power capacity.
- If you want to move your system between different vehicles or from your vehicle to a cabin or other location, a portable system makes the most sense.
This is a fairly simplistic set of guidelines and won’t cover all situations, but it should give you some things to keep in mind as you make choices about your system.
Alternatives to Portable Solar Systems
It’s important to note that solar systems aren’t the only option. In fact, people have been building overland power systems for a long time, and these other setups still may be the best option for certain use cases.
If you go to any campground that allows RVs but doesn’t have electrical hookups, you encounter people using gas power generators. Typically, the generator is being used to recharge a battery system in the RV so it can power the various electrical devices throughout the night and day.
Gas-powered generators offer the advantage of being able to generate electricity when the sun doesn’t shine — at night or in cloudy conditions. The downsides are many – you need to bring fuel for the generator, which is cumbersome. Generators themselves tend to be bulky and heavy. And they are loud, which detracts greatly from the backcountry experience.
Because of the many downsides of gas generators, prior to the availability of small, efficient solar panels, many overlanding enthusiasts used dual-battery systems to leverage the power of their vehicle’s engine to generate and store electricity.
In this setup, a second automobile battery is added so that it charges as the vehicle’s engine runs. You can then draw on that battery to power electronics, without the risk of draining the primary vehicle battery. Dual battery setups are very space-efficient, as all that’s really needed is the battery and some wiring.
One major downside is that they can only charge when the vehicle is running. Installing one is not a trivial task and requires complex wiring harnesses. Also, as with built-in solar systems, dual battery systems that are hard-wired into the vehicle can’t be loaned out or carried away from the vehicle, which limits their versatility.