Are you planning to live full-time in your RV or looking to travel to places you know are off-grid?
Then in our opinion, installing solar panels onto your RV would indeed be a smart investment.
But how many solar panels do you need for an RV?
On average, an RV will need between two and four 200 watt monocrystalline solar panels to offset its energy consumption. The number of solar panels an RV needs depends on the location and daily onboard electrical consumption.
In this article, we will show you how to work out the number of solar panels your RV will need depending on your individual situation.
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How Many Solar Panels Do I Need For My RV?
As with sizing a residential solar installation, the number of solar panels you’ll need for your RV vastly depends on the following things:
- Peak sun hours
- Electrical consumption
- Solar panel output rating
RVs have a slightly different solar setup to the majority of homes mainly because they need to be off-grid, whereas most homes are grid-tied.
We are going to teach you how to size your own RVs solar system, based on the 3 points above. First, we will explain each point, then we will give you the formula to figure out how many solar panels your RV needs.
Peak sun hours
We cannot stress this enough, peak sun hours are the single most important aspect that determines the number of solar panels you will need.
Different locations have different amounts of GHI (Global Horizontal Irradiation). If you don’t know what this is I recommend reading this article.
In short, GHI (peak sun hours) is the solar irradiance that hits the surface of the earth taking into consideration the varying weather conditions.
Each country around the world has different amounts of peak sun hours, without this information you cannot figure out how many solar panels your RV will need.
We have made a resource for Americans, Australians, South Africans, and Brits to figure out their area’s peak sun hours. If your country/area is not covered by our resource, go check out this website.
The second most important aspect of sizing your RV solar system is knowing how much power you consume.
Once you have this information you are able to determine the amount of solar energy that needs to be generated in order to keep your RVs appliances running smoothly.
So, how do you figure out your total consumption requirements?
Well, on average an RV will use between 4 – 15kWh a day. This comes out to roughly 124 – 465kWh a month or 1,488 – 5,580 kWh a year.
With that being said we do recommend making a table like the one below which outlines all the appliances you use in your RV, their wattage, and the number of hours each is used for.
|Appliance||Watt (W)||Hour usage per day (h)||Daily Consumption (Wh)|
|LED Bulbs (x8)||80||5||400|
|Total Daily Consumption (Wh)||4,848|
The amount of kWh used greatly depends on whether the RV uses propane for cooking/heat or electricity. Our example uses propane, but you can update your table accordingly.
Solar panel output rating
Lastly, you need to determine what power rating your solar panel will be.
Most RVs equip either 100-watt or 200-watt solar panels on top of their roof.
Solar Panel Formula For RV (Example 1)
Finally, we have created a formula that you can use to determine the number of solar panels your RV need.
Don’t let this bit of mathematics scare you off, I promise it is very easy to grasp once you get used to the different metrics used.
Okay, so to figure out how many solar panels your RV will need we will use the formula above.
Monthly electric usage ÷ monthly peak sun hours x 1000 ÷ solar panel power rating.
Let’s start with an example.
You plan on driving your RV across Arizona. This state experiences on average 5.7 peak sun hours daily or 176,7 monthly.
So, let’s apply the formula.
First, you need to convert your electricity consumption from Wh to kWh, so 4,848Wh = 4.8kWh.
4.8kWh x 31 days = 148,8kWh monthly.
148,8 ÷ 176,7 = 0,842 x 1000 = 842 watts.
842 ÷ 200 = 4,21
Using our formula you can see that an RV driving through Arizona with 4,8kWh monthly electricity consumption will require x4,21 (200 watts) solar panels to offset all their energy usage. Now of course there are no half panels, so we would recommend rounding 4,21 to 5.
Solar Panel Formula For RV (Example 2)
Let’s do another example with the exact same RV using the same electricity consumption, except this time it is driving through Michigan.
148,8 ÷ 108 = 1,37 x 1000 = 1377 watts.
1377 ÷ 200 = 6,8 (7) solar panels needed for RV in Michigan.
As you can see, the location alone of your RV greatly affects the number of solar panels it will require. With that being said let’s do one more example.
Solar Panel Formula For RV (Example 3)
Let’s use an RV which uses much more monthly electricity than the previous two examples.
Our next RV is using 400kWh a month and is driving through Idaho.
400 ÷ 120 = 3,33 x 1000 = 3333
3333 ÷ 200 = 16,66 (17) solar panels needed for an RV in Idaho using 400kWh a month.
Based on these examples you can see that the number of solar panels needed for a recreational vehicle varies greatly.
Using our formula you should be able to figure out your basic requirements nevertheless.
Unlike grid-tied solar systems, it is very likely your RV will need an off-grid solar system.
Unfortunately, there is just not enough space on the roof to fit say 17 solar panels, therefore your vehicle may need to rely on a battery storage system to provide you with electricity when the weather outside is cloudy/overcast.
But that is all for another article.
Feel free to ask your questions in the comments section below, we would be to help you with any solar/RV-related queries.