No, for the most part you will not be able to run your RV air conditioner on battery power. An air conditioner requires a lot of electricity just to start up. It also requires a lot just to run for an hour. It is possible, however to run air conditioning on batteries. You just need a lot of battery power, along with a lot of solar panels, to help offset your battery draw.
Can I Run My RV Air Conditioner on Battery Power?
A 15,000 BTU air conditioning unit is what most RVs come equipped with these days. Each of these units requires a minimum of 3,500 watts just to kick start a unit. It then takes about 1,500 watts to keep that unit running.
This means you will need at least a 4,000 watt DC-to-AC power inverter, to convert your battery power to usable AC electricity. Most RVs do not come equipped with an inverter of that size. Most RVs do not even come equipped with an inverter of any kind. Those that do, usually come with an inverter ranging from 1,000 watts to 2,000 watts.
You can also add a “soft start” to your air conditioning unit to lower the required starting wattage. Thus, a 15,000 BTU AC unit which would otherwise require 3,500 starting watts, may only need 1,500 to 2,000 watts if equipped with a soft-start.
Only the higher-end RVs come with equipped with a power inverter. These are usually larger fifth-wheel trailers, Class A motorhomes, and higher end Class B vans. Most fifth-wheel trailers and Class A motorhomes come with two to three air conditioning units. Thus, in order to run all two or three air conditioning units, you will need a larger power inverter, perhaps as high as 7,000 watts. No RV or motorhome comes equipped with that high of an inverter.
How Many Batteries Would I Need?
If you had three 100 AH (amp hour) Lithium Phosphate batteries, along with a 7,000 watt power inverter, you could run two 15,000 BTU air conditioning units for about 1 hour. But that will also require you to have about 1,500 watts of solar panels on the roof, to help offset that electrical power draw. On top of that, it would have to be a sunny day in the middle of summer, when you get the best overhead sunshine.
So, if that system will get you just 1 hour of running two air conditioning units, then think about what you will need to run that system for 8 hours. Think about what it would take to run just one air conditioning unit for 8 hours.
Read our other article, “How Much Battery Power Will I Need for Boondocking?”
Why Lithium Phosphate Batteries?
Lithium Phosphate batteries can be drawn down to zero state of charge without suffering damage. Compare that to flooded-cell batteries, or even AGM batteries, which can only be drawn down to 50% state of charge.
In order to get 8 hours of running an air conditioner on battery power, you will need a lot of batteries. A typical 12 volt flooded-cell battery, delivering 100 AH, weighs about 50 pounds. A typical 12 volt lithium battery, delivering 100 AH, weighs about 30 pounds. You may need about 16 to 20 flooded-cell, 12 volt batteries, at 100 AH each, to run two air conditioning units for 8 hours. That could end up weighing as much as 1,000 pounds, and take up a lot space. By comparison, you will need about 8 lithium batteries at 100 AH each, weighing 240 pounds total. That’s a huge difference.
Most travel trailers, either bumper-pull or fifth-wheel models, don’t offer that much cargo carrying capacity. You’d have to buy a toy hauler to get that much capacity, let alone the weight of your other stuff (clothes, appliances, tools, electronics, etc.)
It’s an Extremely Expensive System
A typical 12 volt, 100 AH lithium phosphate battery costs about $1,000.00 each. That means about $8,000.00 in batteries just to get you 8 hours of running two air conditioning units.
That doesn’t count the expense of buying a 7,000+ watt power inverter, which can cost between $1,200.00 to $2,000.00. That also doesn’t count the 1,500 to 2,000 watts of solar panels on your roof, to replenish those batteries while running your air conditioning. That will cost roughly $1,500.00 to $2,000.00 (usually $1.00 per solar watt).
When you include the costs of additional parts (copper wire, battery monitor, 2-way or 3-way transfer switch, solar panel mounting hardware, etc.) you’re looking at spending $11,000.00 to $12,000.000 dollars, just to be able to run two air conditioning units for only 8 hours a day.
And again, that’s assuming you’ll have a bright a sunny day to recharge those batteries.
You can reduce that battery expense by going with Tesla car batteries. Tesla batteries can deliver more power at lower costs. But, they will also require installing a 24 volt system, along with a converter to reduce the final output to 12 volts. There is actually a mobile RV technician that installs Tesla battery banks for RVers.
So Why Bother With Solar Panels and Lithium Batteries?
Most RVers utilize solar panels and lithium batteries to run their DC electrical needs, which are the lights, fans, water pump, power awning, power tongue jack, and other light-duty electrical needs. These provide all the power necessary to boondock comfortably for weeks at a time.
Most boondockers don’t camp in places where they’ll need air conditioning. That is, they camp in higher elevations during the summer where they can get relief from the heat.
If a boondocker still needs AC electrical power, it’s usually for something light duty, like powering a blender, a C-PAP unit, or a television. These things can be run from battery using a smaller power inverter of 500 to 1,000 watts. This also assumes they have a modest sized battery bank of about 200 to 300 AH, and a modest sized solar panel array of 400 to 800 watts.
Solar power, combined with a decent sized battery bank, and a small to medium sized power inverter, is still affordable for RVers who spend most of their time boondocking.
Read our other article, “How Many Solar Panels Do I Need for Boondocking?”
If You Need Air Conditioning, Get a Generator
This is what generators are for. They’re for powering heavy-draw appliances like air conditioning units and microwave ovens. Sure, generators can be expensive themselves, along with being expensive to run for long hours during the day. But, if you want to consume a lot of electricity while boondocking, it is still by far the cheaper alternative.