Determining the Right Solar Power System for Your RV

With the right solar setup, you can have all the comforts of home while exploring the great outdoors. But where do you start? Sizing and installing an RV solar system can seem daunting, especially for first-timers. When it comes to RV solar power, a little planning and forethought can go a long way towards a successful installation.

Conduct an Energy Audit to Assess Your Power Needs

The first step is figuring out how much power you actually need. To get an accurate idea, you’ll need to conduct an energy audit.

Make a List of All Your Appliances and Devices

Grab a notebook and walk through your RV, making note of every single electric item onboard. Jot down the appliance name and its wattage rating (usually listed on a sticker or label on the device). Don’t forget to include:

  • LED lights
  • Water pump
  • Furnace
  • Refrigerator
  • Electronics like laptops, TVs, etc.
  • Anything else that uses electricity!

For devices that don’t list the wattage, look up the specifications online. Measure how many amps an item draws by using a clip-on ammeter. Divide the amps by 12 to get the wattage.

Calculate the Daily Use Time

Now, track how many hours per day you use each item. Be realistic here – sure, you don’t use the water pump all day long, but it cycles on and off frequently.

Say your water pump draws 5 amps. You might use it for 30 minutes each time you need water. If you need fresh water 3 times a day – that’s 30 x 3 = 90 minutes or 1.5 hours per day.

Make your best guess for daily use time for each appliance. For items used for short periods, round up. It’s better to overestimate than underestimate your energy needs.

Multiply Watts x Time to Get Watt-Hours

Next, take the wattage of each appliance and multiply it by the number of hours you use it per day. This gives you the watt-hours of energy consumed.

For example:

  • Water pump – 5 amps x 12V = 60W
  • Use time – 1.5 hours
  • 60W x 1.5 hours = 90 watt-hours

Repeat for every item to calculate the total daily watt-hours consumed.

As an old farm hand once told me, “Measure twice, cut once.” An accurate energy audit will set your solar system up for success down the road.

Use Solar Calculators to Determine Required System Size

Now that you know your total daily energy usage, it’s time to figure out the solar array size needed to meet that demand. There are a few helpful solar calculators that make sizing a breeze:

RV Solar Energy Audit Calculator

This simple calculator from ParkedInParadise lets you input all your RV appliances and usage time. It totals your daily watt-hours and recommends a solar system size. Easy peasy!

RV Solar Calculator

The RV Solar Calculator from RV Columnist includes fields for more details like battery capacity, wiring, and losses. It designs a full system with solar panels, charge controller, batteries, and inverter.

Solar Calculator for RV from AltE

For the most comprehensive analysis, use the AltE RV Solar Calculator. It lets you specify battery chemistry and your typical RV route. The customized results account for solar intensity across the U.S.

I always use the AltE calculator for my RV solar designs. It’s the best way to get a system perfectly tailored to my needs!

Choose Solar Panels to Meet Energy Requirements

Once you’ve calculated your solar power needs, it’s time to configure a system to match. Solar panels come in different technologies, sizes, and power outputs. Here are the key factors to consider:

Solar Panel Types

  • Monocrystalline – Most efficient but priciest option
  • Polycrystalline – Lower cost per watt vs. mono
  • Flexible thin film – Lightweight, bendable panels

Monocrystalline panels are ideal for limited roof space. Thin film works well for curved surfaces. Either will get the job done!

Solar Panel Sizing

Select panels that meet your required system wattage. Power outputs range from 50W to 400W per panel. Combine panels to achieve the total wattage recommended by the solar calculator.

For easy installation, choose 60 or 100W panels. They can be wired in series to produce higher voltages.

Aim to build a system at least 20% larger than your calculated needs. This provides a safety buffer for cloudy weather, future power demands, and degraded output as panels age.

Efficiency and Quality Matter

Research panel efficiency ratings and buy from quality manufacturers like LG, Renogy, or Rich Solar. More efficient panels produce more power in the same surface area.

Higher efficiency and better engineering does come at a premium. But solar panels last 25+ years – a bargain compared to the decades of service they provide!

Carefully Select the Other System Components

Besides the solar panels, your RV power system includes other key components:

Solar Charge Controller

The charge controller regulates the voltage and current from the panels to safely charge your batteries. Make sure to size your controller to handle the total wattage of your solar array.

MPPT controllers are most efficient and can accept a wide voltage range from your panels. Victron, Renogy, and Flexcharge make excellent MPPT controllers.

RV House Batteries

Your batteries store power from the solar panels for use when the sun isn’t shining. For RVs, flooded lead-acid or AGM batteries are good options:

  • Inexpensive and time tested
  • Can handle being jostled around while driving
  • Widely available for easy replacement

Lithium batteries are gaining popularity for their light weight and efficiency. Just be prepared to pay more upfront.

Again, follow the solar calculator’s lead for ideal battery bank size. Allow plenty of capacity for off-grid camping.


An inverter transforms the DC power from your batteries into standard 120V AC electricity to run household appliances and electronics.

Size your inverter for your expected appliance loads. A 2000W unit can run most RV equipment. Get a pure sine wave inverter for sensitive electronics.

Reliable brands are Magnum, Xantrex, and Go Power. Make sure the inverter is compatible with your battery type.

Carefully Plan Solar Panel Placement on Your RV

To maximize power generation, solar panels need open exposure to the sun’s rays. Here are some tips for ideal placement:

Assess Your Roof Design and Area

Consider the roof layout, surface material, and awning coverage. Measure usable area that gets full sun for at least 6 hours per day.

Avoid placing panels near vents or skylights where they could overheat. Leave a 4″ gap between panels for air circulation.

Mount for Optimal Solar Exposure

Tilting solar panels towards the sun increases energy capture significantly. Use roof-level or adjustable mounting racks so panels sit at an ideal angle.

Aim for true south orientation to get sunlight across the broadest arc. But any sun is better than no sun – work with the space available.

Consider Flexible Panels for Odd Shapes

For curved or fragmented roof areas, adhesive flexible panels conform easily. Partial shading only reduces their output slightly.

Flexible panels work great on pop-tops, fiberglass roofs, or even hung outside an RV window!

With smart placement and a well-designed system, your RV can thrive on solar power alone. It’s deeply satisfying to live “off-grid” without the noise, fumes and ecological cost of a generator. Waking up to an unobstructed mountain view, powered by the clean energy overhead – that’s the RV dream.

As someone who’s installed many RV solar systems, there’s nothing better than parking your solar-equipped campervan in the middle of nowhere and having electricity at the flip of a switch.

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