Things to consider when running a caravan air conditioner off a battery

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Are you planning on a long-term caravanning trip during the harsh Australian summers? Have you decided on the air conditioning unit and are you thinking of running it off a battery?

The amount of power required

A caravan air conditioner is most likely the most energy-consuming appliance. There is no disputing that it is a fantastic addition, but you need to keep in mind that the AC unit will consume anywhere in the range of 1000 and 2000 watts when you kick-start it. It will start drawing anywhere between 2000 and 3000 watts when running for say, 4 hours on average. That is gargantuan energy consumption because your laptop will only consume one-tenth of it and your fridge moreover only one-twentieth of it!

Using the battery to run ACs

It is not difficult to run your air conditioner units on lithium battery packs, but it is impractical! Caravans use battery packs and inverters, and chargers to run ACs, but this is not suitable for a longer trip. It will turn out to be very expensive and battery draining.

A 7,000 BTU RV air conditioner will need 1,700 watts for startup and an extra 600 for the compressor to keep running. But a 10,000 BTU air conditioner in your caravan will need 2,000 watts to start and another 700 watts for running. If you have a bigger aircon unit of 15,000 BTU, your minimum need will be 3,500 watts for starting it and another 1,500 for running it.

Can solar power run the caravan air con?

It is theoretically quite possible to run your caravan’s air-con on camping solar panels. But practically speaking, it will need you to set up a large number of such panels and a massive overhauling of your electrical systems. Most caravan owners prefer not to use exclusive solar panels to run their AC.

You will need 750 AH every day in your caravan battery if you intend to use the aircon for a minimum of 5 hours every day. The above estimate is only for the running of the air conditioner. If you want to run your other appliances, you generate another 100 amps from a clear sunny day. On a cloudy day, the requirements will be more. So to power a 13500 BTU air-con, you will need a minimum of 1500 watts of solar panels.

The Pros and Cons of Solar Energy

There are pros and cons to going completely off grid and running your caravan off solar power.

The pros

  • It is a renewable source of energy, and you are not dependent on any artificial external source
  • You will drastically reduce your electricity cost
  • The energy produced may have various applications
  • Very easy to maintain


  • The procuring price is very heavy. There are an inverter, batteries, wiring, and installation costs to look at
  • It is weather dependent
  • Solar panels use up a lot of space

Is a generator a viable option?

An inverter generator is the chosen path for a lot of caravan campers across the continent. It produces clean power that is great for running all the sensitive appliances in your motorhome. The air conditioner is one candidate that requires a clean power source because of its sensitive componentry.

The pros and cons of using generators:

Even using a generator to power your caravan air conditioner has it’s pros and cons


  • Inverter generators are very fuel-efficient than most generators
  • They can idle up and down based on the number of appliances you choose to use in the RVs
  • They can take a huge amount of load without giving up on you
  • They come in a compact casing, usually in a suitcase design that uses less floor space


The only downside of using an inverter generator when away from the mains supply is the constant humming sound you will have to tolerate. Modern generators nowadays come in soundproofing casing, and they can reduce the noise more than the older models. For more tips see our guide to making your generator quieter.

Determining the size of the generator

It is good to ask your AC manufacturer the recommended wattage to start their ACs and run it. Air conditioners usually do not have this information on their product plate, but most popular models require 2400 watts and a maximum of 3000 watts to start and run them. If your air conditioner model has incorporated inverter technology, you can reduce that much from the caravan inverter’s power need.

Extra factors to keep in mind when using generators:

  1. Temperature: the outside temperature and humidity directly affect the power needed by the air conditioner’s compressor. That is why you will need to keep an extra allowance for the power supply if you are out on very hot and humid days.
  2. Extension should be no longer than 4 meters lead from generator to the van because the longer the lead, the amperage drops while traveling.
  3. Simultaneous usage of other appliances: if battery chargers, fridge, television, and laptops are also working, then the energy drawn by the air conditioner may not be enough for its starting up.


A caravan air conditioner is indispensable. It is impossible to think of a comfy and successful motorhome trip in Australian summers without an air conditioner. As long as you are at caravan parks, you may enjoy the power facilities there. How you intend to use your air conditioner once you are away from the parks and main power is what you need to mull over.


Andy Sullivan

Andy Sullivan

A lover of all things outdoors, Andy is an experience camper having traveled the east cost of Australia multiple times and countless trips throughout New Zealand.

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