Cooling from the Sun


Over the last few years, in order to stay in a comfortable climate, I have moved to higher elevations in the summer and lower ones in the winter.  When I was doing a lot of traveling, I roamed around in the northern states to escape the heat of summer, and returned to the desert southwest to escape the cold of winter. This method works well most of the time , but as any nomad can tell you, sometimes you can’t always escape some hot weather or chilly days. As a general rule migration will help you stay in a good climate, but Mother Nature can fool you now and then. 

Staying warm is easy in an RV. We always have furnaces or heaters for cold snaps and chilly mornings. My catalytic heater works well in my little RV and it only sips a little propane. Staying cool when the temperatures unexpectedly rise into the 90’s is another problem altogether. The only way to cool an RV is with air conditioning and that usually involves running a generator or plugging into shore power. I don’t stay in RV parks with hookups and I detest running a generator all afternoon. With all that said I started to think of ways to power an air conditioner from the sun. 

The rooftop AC on my rig does a good job of cooling my motorhome even when temperatures get up to 100°. If not plugged into shore power it requires a good size generator to run. I try to avoid ever being in 100 degree places for very long, but sometimes need a little AC for a rogue 90 degree day where I’m staying. After researching power requirements for small air conditioners and reading about Boondocker that have built systems, I decided to build a solar system to power an air conditioner. 

I won’t go into all the numbers I used to design my system but the basic build is this:  I bought a 5000 btu windows air conditioner that uses about 35 amps @ 13 volts. I increased my solar to a little over 800 watts. I already had a 300 AH lithium battery and 400 watts of solar panels on the roof. I also bought a larger Victron charge controller to basically run the process. It only took me a couple days to install and build the system. 

The magic of a solar powered air conditioner is in the fact that you need most of your cooling when the sun is shining. If I had to run an air conditioner with my battery, the battery would be depleted in a few hours. When I’m getting good solar power, the panels provide all the electricity I need to run the AC and actually will also charge the battery at the same time. As the sun gets lower in the sky my battery takes over and provides power until the night gets cooler. In the morning, the solar quickly chargers the battery back up before the day gets warm. 

One thing I did to increase my solar power is to build a frame that holds some of my panels at angle to the sun. I have four 100 watt panels that I can tilt and rotate to point at the sun. This method requires a little more attention to tracking the sun, but I found that I only have to move the panels about four times a day. It actually gives me something to do and I enjoy the little bit of effort it takes. Later on in the winter as the need for AC goes away, I wouldn’t have to move them at all. 

Right now I’m in Quartzsite at the LTVA. I have to drive back to Tempe for doctors appointment in a couple weeks. I’ll probably drift down to Yuma after that. The Arizona desert is a good place to spend the winter and enjoy the climate. 

3 Responses to “Cooling from the Sun”

  1. Donna says:

    I’m excited to get my own system set up for my future camping needs, though I won’t need all the power you have. You’ve got yourself set up in fine shape for your full time off grid life.

  2. Daryl says:

    You are ready for the zombie apocalypse, except for food and water.

  3. RV John says:

    The good life is possible 😀.

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