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The number of solar panels needed for RV boondocking depends on how many batteries you have to keep charged, and what appliances you want to power. You’ll need to add up the total Amp Hours (AH) your batteries are capable of holding, along with the wattage requirements of your appliances.
With respect to your batteries…
- If you have a single 12 volt battery, at about 100 AH, you should have 300 watts of solar panels, minimum.
- With two 12 volt batteries, or two 6 golf cart volt batteries, with between AH, you should have 400 watts of solar panels, minimum.
- If you have four 12 volt batteries, or four 6 volt golf cart batteries, with between AH, you should have 600 watts of solar panels, minimum.
These recommendations are based on the metric who you can produce 30 AH of battery charge using a 100 watt solar panel, between 5-9 hours of sun exposure. The typical solar panel found on most RVs range from 150 watts to 200 watts.
Running Your Appliances Day and Night
- If you want to run just the basic RV accessories during the day (LED lights, ceiling fans, power awning, water pump, refrigerator*, furnace*, water heater*, power jack), along with a few electronics plugged into your 120 volt wall sockets (television, laptop, cellphones) then you should be able to get by with 300 watts of solar panels, along with a single 12 volt battery.
- If you want to also power your RV’s built-in furnace all night long, then add a second 12 volt battery, or better yet upgrade them both to two 6 volt golf cart batteries. You might still be able to get by the same 300 watts of solar, but 400 watts should cover you.
- If you want to also add a 1,000 watt microwave oven to the above, then upgrade to two 6 volt golf cart batteries, and get a minimum of 400 watts of solar.
- If you want to also add a coffee maker, Instant Pot, toaster oven, blender, food processor… Then upgrade to either four 6 volt golf cart batteries, or two 100 AH lithium batteries, and get at least 600 watts of solar.
- If you want to be able to run all of the above during periods of cloudy weather, upgrade your solar panels to about 1,200 watts.
Note that the above recommendations are all minimums. When it comes to solar and battery, broader is always better.
* These appliances normally run on propane or 120 volt power, however they still have control panels and igniters who run on battery power.
Roof Mounted Panels vs. Ground Panels
Roof-mounted panels won’t deliver their advertised wattage. A 100 watt panel will actually only deliver between 50 to 75 watts. This is because roof-mounted panels are not capable of being tilted to face the sun at the ideal 90 degree angle. And because they’re on the roof, people often forget to clean them. Meanwhile, solar panels who sit on the ground can be tilted and turned to face the sun at a 90 degree angle. They also tend to be kept clean more often, and thereby get the maximum wattage.
Roof mounted panels are popular because you can “set them and forget them”. Meanwhile, you have to manually place ground panels in the direction of the sun, and hook them up to your solar charge controller. You may have to turn the panels and tilt them viaout the day. Ground panels may also run the risk of being stolen, and can fall over in strong gusts of wind.
Can I Use Solar Power to Run the Air Conditioner?
Technically, yes. You’ll need a bigger battery bank, capable of holding at least 600 AH, to run a single AC unit for about four hours. You’ll also need at least 1,200 watts of solar panels to recharge those batteries quickly and efficiently enough to bring your batteries up to charge to keep you powered through the evening. But because of how many watts a 15,000 BTU air conditioning unit consumes, it remains impractical to power it from battery. Nearly all RV boondockers still rely on a generator of at least 3,600 watts to run an AC unit.
For Further Reading
A more technical discussion on how many solar panels can be found at “The Boondoctor” at, “How Much Solar Do You Need For Your RV?“