How Many Solar Panels Do I Need?
The number of solar panels needed for RV boondocking depends on how many batteries you have to keep charged. You’ll need to add up the total Amp Hours (AH) your batteries are capable of holding. The more AH you have, the more solar panels you’ll need…
- 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 volt batteries, with between 200-250 AH, you should have 600 watts of solar panels, minimum.
- If you have four 12 volt batteries, or four 6 volt batteries, with between 400-600 AH, you should have 1,200 watts of solar panels, minimum.
The General Rule of Thumb
These recommendations are based on the metric that 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 100 watts to 160 watts.
Roof Mounted Panels Are Inefficient
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 that 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 throughout 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 13,500 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 3,200 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?”