How Much Solar Panels Do I Need for My RV?

Driving an RV to travel around is cool. But it is worth considering when it comes to the power issue. You won’t want to charge the vehicle frequently when you plan to go out for several days. So installing a solar system on your RV is a good idea.

“How many solar panels do I need for my RV?” is the first consideration that comes into your mind. It is a problem to deal with because solar panels determine the power production that could run your recreational vehicles.

Key points about a solar-powered RV

  • Usually, there are two different electrical systems on an RV: one for the engine and the other for various appliances designed inside the vehicle. Generally, the RV will include a battery for the automotive function, so you need a solar system to run the devices.
  • You may have quite different purposes and ideas about your RV. For instance, some of you want it to contain plenty of devices, ranging from small energy consumers like outlets to big ones such as refrigerators.
  • You should also think about how much room on the roof the RV can offer to install solar panels.
  • You need to take all these factors into account to decide the number of solar panels you need on your RV.

How much energy do the appliances in my RV consume?

To figure this question out, the first thing you need to know is that the energy used to operate your appliances is measured in watts or watt-hour. Some of you may know what watts stand for, some may feel confused.


Watt is an electrical term that refers to the rate of power used to run a particular appliance. And watt-hour (Wh) refers to how much energy per hour the appliance uses. kWh stands for kilowatt-hour, which is equal to 1000 watt-hours. Therefore, to get the answer, you need to calculate the energy consumption of each appliance on your RV, and then add them together.

How to calculate the energy used for one particular appliance?

Firstly, you need to find out the running rate of a particular appliance. We can take the refrigerator as an example. You can find the running rate of the refrigerator on the attached label on the door.

Supposing that the running rate of the refrigerator is 100 watts, it means that the refrigerator needs 100 watts of energy each hour to work. When you drive an RV outside, you are likely to keep the refrigerator working for both day and night without stopping.

Therefore, the total energy for a refrigerator is 100 watts/hour x 24 = 2400 watts-hours. So your solar system needs to provide at least 2400 watt-hours each day.

How to figure out the total amount of energy of all appliances?


To get the sum of the required energy of all the appliances on your RV, first, you need to find out the running rate of each device, and many of them have the given running wattage on their surface. Or you can search the specifications on the internet.

After that, you need to decide how many hours you want each of them to run every day. Then you multiply the running rate by the corresponding running hours as we do in the example of the refrigerator.

Now, you get several values, and you add each of them to get the final result, and it will be the total amount of energy you need to run your appliances.


If you are a layman of calculations, there are also some free online calculators that you can use,  a link is Solar-calculator.

Where should I install the solar panels?


After knowing how much energy you need to run your appliances, you should select solar panels and install them. But before shopping the solar panels, one crucial step is to decide where the solar panels will be installed.

Since the RVs are comparatively large and have plain roofs, the most ideal location for solar panels will be the roof. Also, if they are installed on the roof, it is easy for them to receive sunlight.

Read More: Solar Panel Diagrams – How Does Solar Power Work?

How much room can the roof of an RV provide?

Although each RV has quite different specifications, all RVs certainly have a relatively empty roof for you to place the equipment.

On average, a typical RV has a roof of about 280 square feet. It sounds quite large, but it also includes some necessary settings on the top space, including the vent fans, racks, or skylights. And these things may occupy some areas.


Thus, we can suppose that the total usable space for solar panels is about half of the roof. That means you will get 140 square feet to place your solar panels. According to the research, solar panels can generate 15 watts per square foot, which means a normal RV roof can generate 2100 watts in ideal conditions.

Also, solar panels have different energy rates, and the most common RV solar panels are rated at 100 watts, 200 watts, and 300 watts. So you can decide how many solar panels you want to buy.

Do I need a spare battery?


The answer is yes, but there are several reasons to talk about specifically.

Why do I need a battery bank?

Although solar panels can generate enough energy to keep all your appliances running for a whole day, there could inevitably be bad weather when there is no sunlight. Also, peak sun hours are fewer in some locations. It could be fewer than 5 hours.

So to make sure that the power is always enough to use, you should add a battery bank to store the generated energy as a backup.

What kind of battery should I choose?

Generally, there are mainly two types of batteries: lithium batteries, and lead deep-cycle batteries. Both of them have advantages and disadvantages.

Lithium batteries: They are higher in price, but provide the price-worthy capability.

Lead deep-cycle batteries: Compared with lithium batteries, they are much cheaper, but they are limited. For example, they can only operate when getting over 50% charge.

What is a charge controller?


A solar charger controller is used to prevent your solar panels from overcharging. It interfaces the solar panels and the batteries. Thus it plays an important role in regulating solar power from solar panels to batteries.

It can regulate the amount of voltage transferring from solar panels to your batteries. As we know, if the voltage is too high, the battery could be damaged, especially when you choose to use lead deep-cycle batteries.

There are mainly two types of charger controllers in the market: PWM and MPPT. There are differences and both have pros and cons.


PWM means Pulse-Width Modulation. Compared to an MPPT, a PWM controller is much more economical. But the defect is that it may generate big power losses. According to the data, as much as up to 60% of power can be lost during conversion.

A PWM controller is limited and can not optimize the voltage going to the batteries. Such limitation leads a PWM controller to function with a bug when serving a large system. So it suits smaller systems.

MPPT refers to Maximum PowerPoint Tracking. Unlike a PWM controller, an MPPT controller can effectively optimize the voltage coming from the solar panels. In that case, the produced energy by solar panels can be transferred to the battery bank at a maximum rate.

Accordingly, an MPPT controller has an efficiency of 93%-97% when transforming power. The operation process automatically adjusts to the peak power point fast to achieve the optimal result. So it is a price-worth model to use.

Choosing an inverter


A solar inverter is also indispensable, and it is responsible for converting the direct current(DC) into the alternating current(AC). What are DC and AC?

Simply speaking, DC is a kind of energy form, which is generated directly by the solar panels via receiving sunlight. And it can be transferred to the battery bank in the same form.

But most appliances on your RV can only use the energy of AC form. In other words, the generated solar power can not be directly used by the appliances. So you need an inverter to convert the form of the power so that your appliances can be charged smoothly.


After reading the above article, you will know how to choose a solar panel, and how many solar panels are needed for your RV. Don’t forget to select a suitable battery, charger controller, and inverter too. They can guarantee that your RV solar system operates well.

Plus, you’d better choose solar panels with waterproof and weatherproof. In that case, they can withstand extreme weather conditions so you can use them for a very long period.

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