Your Guide to RV Solar Panels: Components, Installation, and More

Which is more practical for your RV, a generator or solar panels?

Recreational vehicles with solar panels camping off-grid

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It's increasingly common to see solar panels on the roofs of recreational vehicles (RVs). While solar panels can't replace an internal combustion engine and turn your RV into an all-electric vehicle, they can allow you to run your lights and appliances cleanly rather than relying on a fossil-fueled generator.

Solar panels also give you the freedom to camp off-grid and in places that don't allow generators, rather than having to find a spot in a crowded campground with an available hook-up. And of course, with solar panels, you can reduce your carbon footprint.

Here, we discuss RV solar components and whether they are worth investing in for your next RV trip.

RV Solar Components

RV solar is not as simple as attaching solar panels to the roof and plugging in appliances. Here are the main components in an RV solar system.

Solar Panels

Panels can be flexible, portable, or rigid. Lightweight flexible panels are better suited when an RV roof is molded rather than flat, while portable panels can be placed anywhere on or off the vehicle, so they can capture sunlight even if the RV is parked in the shade. Rigid panels are much heavier, but they are also more durable and less expensive. Panels may generate 150 watts in flexible and portable panels and up to 250 to 300 watts in rigid panels.

Batteries

Most RVs have two batteries. A 12-volt lead-acid/AGM starting battery is used to start the engine, while a 12-volt RV "house" battery bank is used to run the DC-powered appliances, such as fans, lights, and water systems.

An AC/DC inverter can provide 120-volt power from a "shore power" hookup at an RV campground to power air conditioners, microwaves, and other energy-intensive appliances. In more modern RVs, older lead-acid RV battery banks have been replaced by lithium iron phosphate batteries charged by solar panels and the RV's engine alternator via DC/DC chargers. Together, these provide much more rapid charging and much longer-life battery banks, especially suited for off-grid use.

Some RV owners upgrade to lithium-ion batteries, which are lighter, more efficient, maintenance-free, can hold more energy, and have a longer lifetime. The downside is they cost significantly more.

Solar Charge Controller

A solar charge controller protects your battery by regulating the flow of electricity from solar panels to the battery. The controller matches the voltage output of the solar panels to the voltage capabilities of the battery or batteries.

Inverter 

Many RVs already have inverters that convert DC power from your 12-volt battery into 120-volt AC power used by your lights and other electrical equipment. More expensive inverters can produce more reliable and consistent power needed to run sensitive equipment like electronics or medical equipment.

Transfer Switch

A transfer switch allows you to switch the source of your power from the battery to shore power when parked in a campground, or to turn off a propane source when you are driving.

Solar vs. Generator: Which Is Better?

Generator in rv campground
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It's no surprise that solar panels are more environmentally friendly than fossil-fuel generators. Here are some other factors to consider:

  • Energy: Solar panels require adequate sun to charge your batteries, while generators require adequate fossil fuels.
  • Space: A generator and its fuel take up a significant amount of interior storage space. Solar panels are limited by the amount of roof space.
  • Flammability: Fuels for generators (usually diesel, gasoline, or propane) are flammable. Some states prohibit the use of propane generators while driving.
  • Maintenance: Generators need regular maintenance and can leave sulfate residues in batteries. With no moving parts, solar panels need little maintenance other than dust and debris removal.
  • Power Speed: Generators provide instant power. Solar power is slower.
  • Costs: Solar panels usually cost more to install than a generator, but once installed, the sunshine is free and infinitely renewable.
  • Noise: Running a generator at night in a crowded campground will not win you any friends. Absolutely quiet solar panels, however, do not generate anything at night.
  • Emissions: Generators emit greenhouse gases, carbon monoxide, and particulate matter, while solar panels are emissions-free. The manufacture of solar panels is not carbon-free, but neither is the manufacture of generators or the fossil fuels that run them.

Installing Solar Panels on Your RV

Installing solar panels on an RV is no more complicated than installing them on the roof of a home.

Treehugger Tip

If you are uncomfortable or inexperienced in working with electrical systems, hire a professional, such as a professional RV converting company.

When you're ready to purchase and prepare for installation, remember to:

  • Calculate how many panels you will need. Identify the power requirements of your appliances and how many hours per day you use them.
  • Consider what equipment your RV already has. A number of RVs for sale on the market already come solar-equipped or solar-ready. For safety and efficiency, be sure that your RV has heavy-gauge wiring adequate to supply the full amount of power from your panels to your batteries.
  • Buy everything at once. Each component of your RV solar system needs to be compatible with each other. RV solar panel kits are more expensive than buying each component separately, but their components are already compatible.

Installing an RV solar system consists of upfront costs that can be expensive. But these costs may save you money in electricity and fuel costs, as well as camping fees. Solar panels will also reduce your greenhouse gas emissions. If you want to go completely emissions-free, consider a car-camping road-trip in an electric vehicle.

Frequently Asked Questions
  • How many solar panels do I need for an RV?

    Depending on the amount of sunshine you get and the amount of energy you use, a single 100-watt solar panel is likely to be able to keep a 12-volt DC battery charged. It is likely you'll want multiple higher-wattage panels and perhaps multiple batteries to give you more power for a longer period of time.

  • Are solar panels worth it for RVs?

    Depends on your usage. The larger upfront cost of solar panels, compared to a generator, pays itself off if you frequently rely on solar power off-grid. However, if you only park your RV in campgrounds with shore power, it's probably not worth your money and effort to invest in solar panels.

  • How much do solar panels for an RV cost?

    If your RV is not solar-ready, you may need more than a minimal 100-watt solar panel kit with mounting brackets and a solar charge controller, which can cost as little as $150. With a lithium-ion battery and multiple panels on your roof, the cost can be a few thousand dollars.