How much solar power do I need for my RV

“How much solar power do I need for my RV” is a common question to think about if wanting to use solar energy. But why switch to solar in the first place? Conventional energy supplies in RV’s come from on-site plug-in electricity, batteries and fuel-powered electric generators.

These are all effective ways to power your electrical appliances in your RV. Do you want a potentially limitless supply of energy? That’s what solar energy offers. With some effort, you can install a system to power all your appliances for free (minus the setup cost).

This article will tell you everything you need to know about solar energy should you want this system in your RV.

How does solar energy work

As an introduction to solar energy, it would be smart to understand how the system works. Essentially solar panels have large surface areas to absorb as much sunlight as possible. It’s this sunlight that produces a direct current (DC).

This flows to an inverter which converts it into an alternating current (AC). It’s this current which you would find at a house, and it’s what household appliances run off of. Check out the following video for an in-depth description of how solar panels work.

An Example of an RV solar system

Now you have an idea about what solar power actually is, the next thing is to see exactly how the system operates practically. The below diagram from ThefitRV is one of the best examples I could find of an RV solar system.

This diagram shows a typical safe solar setup. The number of solar panels dictates the amount of power the system can produce. The DC generated from the panels flows to the solar controller, which sends the current to the converter.

The converter changes the DC from the panels to AC which leads to the AC panel. From here, the AC will flow to the outlets you have in your RV. These outlets are most likely sockets like you would see in a house. This is what allows RVs to be homes on wheels as you have all the facilities you’d have at home. Now you know what a solar system looks like, it’s time to create one to meet your power needs.

How much power do I use?

Before you even start putting a solar set up in your RV, it is important to know your power needs. This way, you can build a system that has a capacity greater than what you need. If you don’t have enough capacity, you will trip the system and shut off the entire electrical system.

When it comes to solar panels, there is a range of shapes and sizes. Solar panels have a wattage rating which is the number of watts they can produce. A typical small solar panel will have a rating of 100 Watts, whereas a bigger panel may have a rating of 200 Watts.

It’s common to find that you’ll need more than one solar panel, so they are usually sold in sets. From this point, you can decide whether to have one solar panel or ten; the number you decide on depends on your electrical needs.

Working out my electrical needs

There is a variety of ways to work out your electrical needs. The first thing to do is list what appliances you use and the power they require. A typical example could be as follows (please note that the numbers are not representative of actual devices. Please use the specific electric information on your devices to work out your electrical needs).

1. A kettle – 2000 Watts, 8 Amps.

2. A microwave – 800 Watts, 4 Amps.

3. A laptop charger – 100 Watts, 2 Amps.

4. A fridge – 50 Watts, 2 Amps.

5. A hairdryer – 500 Watts, 4 Amps.

Wattage total: 3450

Amp total: 20

Therefore, in theory, you’d need enough solar panels to deliver 3500 Watts and a 20 amp current to run all of these at once. The likelihood of running all of these simultaneously is low, and it would be costly to create a system to produce this kind of power. Just for the solar panels alone, you’d be looking in the thousands of pounds price range.

A smarter way of designing a system is thinking about what you are likely to have running simultaneously and then build a system with enough wattage to cover this comfortably.

For example, the fridge will always be running, so that’s 50 Watts. Along with a laptop and phone charger that’s another 150 Watts. Then you may use the microwave now and again at 800 Watts, giving you a 1000W total. Factoring in some additional capacity, let’s say 20%, you could make the total 1200 Watts.

Whatever number you end up with is what wattage your panels need to total to run everything you need. The simple reality is the more power you use; the more solar panels will be needed.

Solar snag ups

In theory, the above system will deliver whatever power output its max capacity is. The reality is several factors are likely to affect this. Solar panels aren’t 100% efficient, so it’s normal for them to lose capacity over time. Take a standard 100W solar panel. It may only be able to produce 95W (a 5% reduction).

The second issue is the most obvious and is down to the sun. It would help if you had good sunlight to power the system in the first place. Therefore if you are camping in California in the middle of summer, your sun supply is likely to be plenty.

Contrasted with winter in Scotland, where the sun may never be out. An increasing amount of RV owners put their solar panels on adjustable roof panels, which lift to 90 degrees. This way, you can maximise the sun they get.

Another prevalent issue involves unknown damage and dirty solar panels. As they are on the roof without access to a roof rail, they can go unchecked. This can cause problems, Such as they might get covered in bird poo, reducing the surface area of solar.

In some, cases after winter storage, they can get mouldy. In some unlucky instances, they can fall off due to a bad DIY job. Some do get stolen due to their high cost.

Like any product, solar panels and the system needs regular maintenance. Before every trip, it’s smart to give the system a test and a once over. Checking cable connections, cleaning the panels and running appliances.