It’s a big question that always comes up on every RV forum; can I run my RV air conditioner on solar? How many solar panels will I need to run the RV A/C on solar?
While it is possible, unfortunately, running your RV A/C on solar is neither simple or cheap. In order to generate enough power, you need a huge number of solar panels, as well as extra batteries and upgrades to the electrical system. Thus, as a practical matter, most RV owners will not be able to get their RV set up in such a way that the air conditioner is running for hours on solar power.
Let’s go over some facts and figures:
Running the RV AC on Solar Is a Lot of Power
RV air conditioning units use lots of power; in fact, the A/C likely uses way more than all your other electrical devices combined. The only other RV appliance that rivals the A/C in power consumption is the microwave oven; however, the microwave isn’t running for hours at a time, all day every day.
To power, a typical 13,500 BTU RV air conditioner for five hours a day, the air conditioner will require 750 Ah per day from the batteries.
To meet this need, your solar panels would need to generate 107 amps for 7 hours every day; and this is on a clear, sunny day. You would need more if it’s cloudy.
How Many Solar Panels to Run the A/C?
In order to feed that much power into your batteries, it’s been estimated you would need 1,500 watts of solar panels at a minimum. Some estimate you would need 2,000 watts of solar panels. If you have 20x 100W panels, that adds up to over 120 square feet of roof space. Also, a 100w solar panel averages $100-150 in cost. At a minimum, you would need to spend $1,500-2,000 on solar panels. Also, a 100w solar panel weighs around 16.5 lbs, so twenty 100w panels would weigh n at 330 lbs.
Unfortunately, only the largest bus conversion could possibly carry that many panels on the roof. If you were to set some panels up on the ground, you would need a considerable amount of storage space.
The Battery Bank
With your air conditioner taking up 150 amps, you would need at least 150 Ah for everything else, every hour the air conditioner is running without full sunshine. Thus, the battery bank needs to be significantly larger, not only to run the A/C but to run other things and to compensate for days without abundant sunshine.
For example, rather than having the typical 300 Ah battery bank, you would need at a minimum 700 Ah. This will allow the battery to last during nighttime and cloudy hours. However, a 1,000Ah lithium battery bank is probably more realistic. Batteries are also very heavy and expensive; a typical 100Ah lithium battery for an RV cost at least $250 and weighs 65 lbs or more. That would cost a minimum of $2,500 and 650 lbs in weight for 1,000 Ah of lithium. Even if you have the money, can your RV carry that much extra weight?
The Power Inverter
The inverter required to power an air conditioner needs to be extremely large. For a 13,500 BTU air conditioner, you would need a 3,000-4,000w pure-sine inverter. This Aims 4,000W pure sine inverter on Amazon goes for around $900.
While it is possible to run your RV air conditioner on solar, it is a very expensive and weighty proposition. It could cost $5,000 at a minimum, and add around 1,000 lbs of extra weight to your RV.
Alternatives to RV A/C
The first obvious solution to cooling to summer heat is to drive away, off to a cooler climate. Be sure to make your reservations for cool summer areas well in advance; everyone wants to escape the heat, so plan accordingly.
Another solution is to run a portable evaporative cooler. However, this solution is only good in dry climates! A “swamp cooler” will not work in humid places like Florida or the gulf coast.
There are portable units, as well as rooftop units made for RVs. However, installing a rooftop RV evaporative cooler will require some complex installation.
If you really need your A/C in the summer, the best bet would be to plug in at an RV park; there are quite a few decent RV parks for less than $400 a month. In any case, it’s up to you whether outfitting your RV with solar-run air conditioning is worth the cost, or the weight.