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.
Electrical consumption
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) |
|---|---|---|---|
| Small Fridge | 40 | 24 | 960 |
| Microwave | 800 | 0.5 | 400 |
| Plasma TV | 200 | 4 | 800 |
| Cellphones (x3) | 54 | 2 | 108 |
| LED Bulbs (x8) | 80 | 5 | 400 |
| Laptop (x3) | 300 | 4 | 1200 |
| Coffee Maker | 1000 | 0.15 | 150 |
| Water Purifier | 60 | 1 | 60 |
| Blender | 500 | 0.1 | 50 |
| Water Heater | 1440 | 0.5 | 720 |
| 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.
We would recommend 200-watt solar panels for your RV, like the ones from Renogy or Newpowa for example.
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.
Final Thoughts
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.
This means your RV will rely on components other than just solar panels such as a charge controller, inverter, and solar batteries.
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.
When your RV isn’t in use, you only need 200 watts of solar electricity to keep your battery bank charged. Traveling by RV, on the other hand, will necessitate more. A 700-watt solar system for toy haulers was successfully installed by me. This appears to be the sweet spot for many RVers who use inexpensive inverters.
Can you tell me what ALL I need to be able to run completely off grid or run fully solar meaning a/c fridge tv microwave. I currently have a 7,000 watts generator which is getting very expensive I also have 100 watts solar panels connected to a battery and that takes care of fridge and lights only. It’s getting hot and I’d like to run a/c all the time at least.
Hi Norma,
If you could give me a list of all the appliances you would like to run, their wattages, and the amount of time you would like to run them for, I can give you a breakdown of what system size you will need. Also, where are you located currently?
Feel free to take this over to the forum too: https://forum.climatebiz.com
Hello I’ve been trying to figure how many panels I would need can u please help. I use the fallowing.
Flat screen tv 120v.60hz 0.8 a
Xbox gaming system 170 watts 2.42 amps
Box fan 120 volts
Norcold fridge 120 amps 14 watts
Led lites 12 volts
Security camera 12 Volts dc / 500 MA
Use of items
Between game n tv run about 10 hrs if that.
Fan 8 hours
Lites when necessary
Camera 15 hrs
My area is Calif.
South peak hours 5.2 but have min 12 of sun lite
Hi Kenny,
So as it stands you want to run the following:
Flat Screen TV: 100 watts (10 hours) – 1000 Wh
Xbox: 170 watts (10 hours) – 1700 Wh
Fan: 30 watts (8 hours) – 240 Wh
Fridge: 50 watts (24 hours) – 1200 Wh
LED Lights: 10 watts (5 hours) – 50 Wh
Security Camera: 15 watts (15 hours) – 225 Wh
Total watt hours usage per day: 4415 Wh
Total watt hours usage per month: 132 kWh.
Now we can use the formula provided: 132 (energy usage) / 156 (peak sun hours) = 0.846 x 1000 = 846 watts.
This means you would need an 846-watt solar system to offset your energy usage.
Please note, that this is a very rough calculation. other considerations such as inefficiencies have not been taken into consideration. Also, I have calculated your watt hour usage roughly based on the limited information you provided me.
I hope this helps.
Yes it helps alot I thank you very much at least I now have a number to run with in order to by a solar kit. Thank you again for yr time n help. Have a great day
Hey there so I have a pull behind camper. Only going to be using solar to charge a phone or two, a mini fridge and a fan or two. The camper is roughly 20’. I’ll only ever have the mini fridge constantly running. Not sure how big of a solar panel I’ll need. Thank you in advance.
Hey Brandon, if you could share the total wattage rating of your fridge?
We are prewired for ZAMP and have been advised that battery needs to be at 70% or more to charge. Is this the case with all solar and why. Thanks for any info on this.
Hi David, thanks for reaching out. This all depends on which type of battery you buy. Different battery technologies have different DoD’s.
I would recommend checking out some of our other dedicated articles on batteries. We have quite a lot of information on the subject.
You can find those articles here: https://climatebiz.com/category/solar-batteries/