Are you wondering what size solar panel you need for your RV, Motorhome or Caravan?

You’re not alone! This is a question we get all the time. That’s why I’ve put together this article to help clear everything up for you.

I want to make sure you have all the information you need to make the best decision for your needs. After all, getting a solar panel system for your RV is a big investment!

Let’s take a look…

The Number of Solar Panels Needed For Your Motorhome or RV

You RV will need on average 200 watt monocrystalline solar panels. This average is based on using 100 watts of power per day.

If you use more power than this, you will need to increase the number of panels in your system.

If you have an RV with a roof that’s around 200 square feet, then you’ll need at least four panels to generate enough power for your needs.

There are also three things to consider when you’re working out how many panels you need:

  • Sun hours at their highest point (peak point)
  • Electrical usage
  • PV solar panel output rating

Sun hours at their highest point (peak point)

Have you ever heard of GHI (Global Horizontal Irradiation) or DNI (Direct Normal Irradiation)?

No?

Not a problem. I’ll be honest, until I started researching this, I didn’t either.

GHI is the total amount of solar radiation that hits a particular spot on Earth’s surface during the day. DNI is a measure of the intensity of the sun’s rays.

You need to take both of these into account when working out how many solar panels you’ll need for your RV.

The average sun hours at their peak point is around 6.5 hours. But this can vary depending on where you live. For example, Arizona gets more sun hours than Alaska.

You can check the average sun hours for your area on the National Renewable Energy Laboratory’s website.

Electrical usage

How much power do you use on a daily basis? This is something you need to consider when working out how many solar panels you’ll need.

The average RV uses around 100 watts of power per day. But this number can increase or decrease depending on how you use your RV.

Solar panels for an RV should be 200 watts or more, such as those from Renogy or Newpowa.

Those are the most popular brands, but there are other options available as well.

For example, if you like to camp off the grid, then you’ll need more power for things like running a fridge and charging your laptop. But if you only use your RV for short trips, then you won’t need as much power.

You can get an idea of your daily power usage by keeping track of how much you use over a week or month. Then you can average it out to get a good idea of your needs.

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PV solar panel output rating

The PV in PV solar panel stands for “photo voltaic.” This is the process that converts sunlight into electricity.

Solar panels have a rating that tells you how much power they can generate. This is measured in watts.

A solar panel of 200 watts, for example, may deliver 200 watts of electricity each hour.

You need to take the output rating of your solar panel into account when working out how many panels you’ll need for your RV.

Let’s have a look at an example to give you an idea of how this works:

(Example 1) Solar Panel Formula For RV

So, to figure out how many solar panels your RV will need, use the following formula:

monthly electric consumption ÷ monthly peak sun hours x 1000 ÷ solar panel power rating.

For example:

You’ve decided to travel across Texas in your RV. This state has on average 5.9 peak sun hours each day, or 177 per month.

First, you must convert your Wh consumption to kWh, so 4,848Wh = 4.8kWh. monthly or over 31 days works out to 148,8kWh.

With that figure, we can then say:

148,8 ÷ 177 = 0,840 x 1000 = 840 watts.

840 ÷ 200 = 4,20

Because we calculated the solar requirements for an RV with 4,8kWh monthly energy usage traveling through Texas, you may see that it will require x4,20 (200 watts) solar panels to offset all of their power use.

There’s no sense in working with half panels, so we’re better off rounding the suggested solar panel amount to 5.

Can you see how this works?

Now let’s look at another example:

(Example 2) Solar Panel Formula For RV

This time, we’ll use different numbers to show you how the calculation works.

Let’s say you’re travelling across America in your RV. You know that you’ll be using around 9,000 watt-hours (Wh) of power each month.

First, you must convert your Wh consumption to kWh, so 9,000Wh = 9kWh. monthly or over 31 days works out to 290,3kWh.

The average sun hours across America is 5.5, or 166 per month.

With that figure, we can then say:

290,3 ÷ 166 = 1,74 x 1000 = 1.740 watts.

1.740 ÷ 200 = 8,70

Using our calculation, you can see that an RV with 9kWh monthly energy usage driving across America will require 8,70 (200 watts) solar panels to offset all of their power consumption.

There’s no sense in working with half panels, so we might as well round down the suggested solar panel quantity to 9.

As you can see, the amount of solar panels you’ll need for your RV can vary depending on a number of factors. But by using the formula above, you can work out a good estimate of how many you’ll need.

Solar Power Jargon

You’ve likely heard the names amps, volts and watts and wondered what they meant in relation to solar power.

Let’s have a quick look at these terms so you can understand them:

Watts

A watt is a unit of power and is the product of volts and amps.

For example, a 100-watt solar panel designed for RVs produces 100 watts of power. This could be 5 amps at 20 volts or 10 amps at 10 volts.

The important thing to remember is that the higher the wattage, the more power the solar panel produces.

Amps and Volts

Amps (amperes) are a unit of measurement for electrical current. Volts are a unit of measurement for electrical potential difference.

You can think of it like this: Amps measures the flow of electrons and volts measure the pressure at which those electrons flow.

The higher the amps, the more electrons are flowing. The higher the volts, the greater the pressure or force with which those electrons are moving.

For example, a 100-watt solar panel produces 8.3 amps at 12 volts or 4.2 amps at 24 volts.

You’ll see these terms used a lot when discussing solar panels and batteries as they’re an important part of understanding how the two work together.

Now that you know the basics of solar power, let’s move on and look at the different types of solar panels.

Related: Can You Run A Whole House On Solar Power? (MAYBE?)

Types of Solar Panels

Solar panels come in a range of shapes, sizes and efficiency levels. But there are two main types that you’ll need to choose from:

  • Monocrystalline solar panels.
  • Polycrystalline solar panels.

The type of solar panel you choose will likely come down to a matter of preference as both monocrystalline and polycrystalline panels have their own set of pros and cons.

Let’s take a look at each one in a little more detail:

Monocrystalline Solar Panels

Monocrystalline solar panels are made from a single, large crystal of silicon. They’re also known as single-crystal, mono-silicon or single-crystal silicon solar panels.

Monocrystalline solar panels are the most efficient type of solar panel on the market today. They have a higher efficiency rating than other types of solar panel, which means they’re able to convert more sunlight into electricity.

Monocrystalline solar panels also have a higher power density, which means they produce more electricity per square metre than other types of solar panel.

Monocrystalline solar panels tend to be more expensive than other types of solar panel, but they’re also more durable and have a longer lifespan.

Related: How Many Amps Do Solar Panels Produce?

Polycrystalline Solar Panels

Polycrystalline solar panels are made from multiple small crystals of silicon. They’re also known as multicrystalline, multi-silicon or poly-silicon solar panels.

Polycrystalline solar panels have a lower efficiency rating than monocrystalline solar panels, but they’re also cheaper to manufacture.

Polycrystalline solar panels tend to be less efficient in lower light conditions, but they perform better in high temperatures.

Polycrystalline solar panels also have a shorter lifespan than monocrystalline solar panels and are not as durable.

The most popular type of solar panel on the market today is the monocrystalline solar panel. But there’s no right or wrong answer when it comes to choosing between monocrystalline and polycrystalline panels.

It really comes down to a matter of personal preference and what you’re looking for in a solar panel.

Do Batteries Help?

Absolutely, batteries are an essential part of any solar power setup. They provide a way to store the electricity that your panels generate so that you can use it at night or on cloudy days.

Solar batteries come in all shapes and sizes, from small 6-volt ones to large 12-volt ones. The size you need will depend on how much power you want to be able to store.

As a general rule, the more batteries you have, the more power you can store. But they also add weight to your RV, so you’ll need to strike a balance between power and weight.

If you’re not sure how many batteries you need, a good rule of thumb is to use one battery for every 100 watts of solar panels. So, if you have 400 watts of solar panels, you’ll need at least 4 batteries.

There are two main types of batteries that you can choose from: lead-acid and lithium-ion.

Lead-acid batteries

The most popular battery type used in RVs is a lead-acid one.

They’re relatively inexpensive and easy to find. But they’re also heavy and require more maintenance than lithium-ion batteries.

Lithium-ion batteries

Lithium-ion batteries are the new kids on the block and are slowly becoming more popular in RVs.

They’re lighter than lead-acid batteries and don’t require as much maintenance. But they’re also more expensive.

Whichever type of battery you choose, make sure that it’s designed for deep cycling. This means that it can be discharged and recharged multiple times without damaging the battery.

Deep-cycle batteries are different from the car batteries that you might be used to. They’re designed to slowly discharge over a long period of time and then be recharged.

This makes them perfect for use in RVs, where they can be used to power everything from lights to fridges.

If you’re not sure what type of battery to choose, talk to a qualified solar installer. They’ll be able to help you select the right batteries for your RV and show you how to install them.

Related: RV Solar Panels vs Generators | What’s Better When Camping?

FAQs

What if I don’t have enough sun?

If you don’t have enough sun, you can supplement your solar panels with a solar generator. This will give you the power you need when there’s not enough sun to power your RV.

Do I need batteries?

Batteries are an essential part of any solar power system. They provide a way to store the electricity that your panels generate so you can use it at night or on cloudy days.

How many batteries do I need?

As a general rule, you’ll need one battery for every 100 watts of solar panels. So, if you have 400 watts of solar panels, you’ll need at least 4 batteries.

Do RV parks have solar power?

Yes, some RV parks have solar power. But it’s not as common as you might think. Most RV parks are powered by the grid, which means they’re not ideal for RVs that rely on solar power.

Do I need a special RV to use solar power?

No, you don’t need a special RV to use solar power. Any RV can be outfitted with solar panels.

About the Author

Passionate about helping households transition to sustainable energy with helpful information and resources.

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