Overlanding Solar Power Setups: How to Size and Build One
Updated September 2026.
Every overlander runs into the same problem sooner or later: a fridge, lights, and devices that need more power than a parked vehicle can give without draining the starter battery. Idling the engine burns fuel and makes noise in camp. A generator takes up space and needs its own fuel. For most rigs, solar is the quiet answer, as long as you size it honestly.
How a solar setup works
A 12V solar system has four parts:
- Panels turn sunlight into DC electricity.
- A charge controller sits between the panels and the battery and regulates charging so the battery isn't overcharged.
- A battery stores the energy. Solar doesn't run a fridge directly. The battery does, and the panels refill it.
- Loads are what you run. Fridges, lights, fans, and USB chargers run straight off 12V DC. An inverter, which converts DC to household AC, is only needed for AC appliances, and it wastes some energy doing the conversion.
A portable power station bundles the battery, charge controller, and outputs in one case.
How much solar you need
Work backward from what you run.
- List your daily loads in watt-hours. Watt-hours are watts multiplied by hours of use. The fridge is usually the biggest daily load, and its use depends on outside temperature, setpoint, and how often you open it. If you can, measure it for 24 hours with an inline DC meter.
- Size the battery. It should cover your daily load for as many days as you might go without sun or driving, with room to spare. Usable capacity depends on chemistry: lithium iron phosphate batteries can use most of their rated capacity, while lead-acid batteries last longer if you avoid draining them deeply.
- Size the panels to refill the battery. Multiply rated panel watts by the hours of strong sun you expect, then plan on noticeably less, because heat, dust, sun angle, and shade all cut into output. If solar harvest plus alternator charging covers your daily use, you're balanced.
Rigs that drive most days can get by with less solar because the alternator does much of the charging. Rigs that park for days at a time lean on solar and need more of it.
Solar options for overlanding
Portable panels
Folding panels set up anywhere and can be aimed at the sun and moved as it tracks across the sky. That means you can park the truck in the shade and put the panel in the sun, which matters in the desert. The trade-offs are setup time, a cable run to the vehicle, and security when you leave camp.
Roof-mounted panels
Fixed panels on a roof rack or canopy charge whenever the vehicle sits in the sun, including while you drive, with nothing to set up. Because they lie flat, they harvest less early and late in the day than an aimed panel, and they only charge when the vehicle itself is parked in the sun.
Charge controllers
The controller manages charging from panel to battery. MPPT controllers generally get more out of the same panel than simpler PWM controllers, especially in cold weather or when panel voltage runs well above battery voltage. For overlanding, look at combined units that include a DC-DC charger. They charge the house battery from the alternator while you drive and from solar in camp, so both charging sources run through one box. Controllers are rated by the current they can handle, so size yours to your panel array.
Portable power stations
A power station lets you plug a panel straight into a battery without wiring anything into the vehicle. The one we carry is the Dometic PLB15, a compact 15Ah LiFePO4 pack that stores up to 192 Wh at 12V and accepts solar input. It covers devices, lights, and short fridge stretches on day trips and weekends. Running a fridge for several days without driving takes a much larger battery.
Camp lighting
Small solar lanterns are fine as backups, but a rechargeable lantern topped up from the vehicle or a power station is more dependable. The Fenix CL27R charges over USB-C in about 2.5 hours and runs up to 285 hours on its lowest setting. Browse lighting and power for more.
Setting up your system
Choosing equipment
Buy panels, controllers, and cabling rated for outdoor use and vibration. Monocrystalline panels are the common choice for vehicles because they produce more power per square foot than polycrystalline panels. Flexible panels weigh less and fit curved surfaces, but mounted flat against a roof with no air gap they run hot, and heat lowers output.
Positioning panels
Put panels where they see open sky for as much of the day as possible. Shade on even a small part of a panel can cut its output sharply. Angle portable panels toward the sun and re-aim them a few times a day. A steeper tilt helps in winter, when the sun sits low.
Connecting and storing energy
Use cable sized for the current and the length of the run, fuse the positive side near the battery, and make sure every connection is tight. A loose or undersized connection wastes power as heat. Follow the maker's instructions for your controller and battery. If you're adding a second battery to the vehicle, our dual battery guide covers isolators, DC-DC chargers, and battery types. If fusing and wire gauge are new to you, have a qualified installer do the work.
Maintenance
Wipe dust off the panels regularly, which in Arizona means often. Check connectors, cable runs, and mounting hardware after rough trails. Watch your battery monitor over a few trips so you know what normal looks like, and look into it when harvest drops.
Getting more from the power you have
- Know your numbers. A battery monitor or your controller's app shows what goes in and out. Most people are surprised by which loads matter.
- Run heavy loads midday, when the panels are producing the most, so the battery isn't doing all the work.
- Cut the fridge's workload. Keep it out of direct sun, pre-chill food at home, keep it full, and open it less. Better insulation helps too: the Dometic CFX5 45 uses vacuum insulated panels and a variable-speed compressor to hold its setpoint with less run time. Browse all fridges and coolers.
- Keep a backup charging source. Driving with a DC-DC charger fills the gap on cloudy days.
Common questions
How much solar do I need for overlanding?
It depends on your daily load and how often you drive. Add up the watt-hours your fridge and devices use in a day, then size the panels so expected harvest plus alternator charging covers it with room to spare. A rig that drives every day needs less solar than one that parks for a week.
Can I run a 12V fridge off a solar panel?
Not directly. The fridge runs from a battery, and the panel recharges that battery through a charge controller. You can't skip the battery.
What can I run on a 400 watt solar system?
Panel wattage alone doesn't decide that. The battery does. In good sun, 400 watts of panels can keep a well-sized battery topped up for a 12V fridge, phones, laptops, cameras, radios, LED lights, and fans. Anything with a heating element, like a hair dryer or kettle, needs a large battery and an inverter no matter how many panels you have.