Ultimate Guide: Running Your Caravan Air Conditioner From a Battery

If you’re wondering how to power your caravan air conditioner when you don’t have access to mains power, you’re not alone. Your two main options are a small portable generator or your caravan’s battery system. 

So, can you run your caravan air conditioner from a battery?

Yes! It is possible with the right RV battery setup, but there are several important things to understand before attempting it.

 

Air Conditioners and Power Draw

Let’s start with how much power a caravan air conditioner actually uses. The Dometic FreshJet Pro features an advanced inverter compressor system, which delivers efficient performance and a very low startup power draw. Instead of a sudden surge, the compressor gradually ramps up to full power, reducing strain on your power system. The peak power consumption is approximately 1600W (cooling mode) for this particular air conditioner which is vital information to know what you need in your system to keep you powered. Once the compressor settles, running consumption averages around 1000w. 

 

What Inverter Do I Need?

With a peak load around 1600W, you’ll need a quality 2000W pure sine wave inverter, such as:

 

Enerdrive ePOWER 2000W 12V Pure Sine Wave Inverter

The Enerdrive ePOWER 2000W Pure Sine Wave Inverter is a great match for powering inverter-style caravan air conditioners like the FreshJet Pro. It delivers reliable, clean power with enough continuous output and surge capability to comfortably handle the soft-start compressor ramp-up. Its high efficiency means less strain on your battery system,

Key Specs & Features:

• 2000W continuous output

• 4000W surge rating

• Pure sine wave power ideal for sensitive electronics

• High-efficiency design for reduced battery drain

 

Renogy 2000W 12V to 230V/240V Pure Sine Wave Inverter (budget-friendly)

The Renogy 2000W inverter converts a 12V battery system into clean 230/240V AC power, making it a solid choice for powering inverter-style caravan air conditioners and other household appliances while off-grid. Thanks to its pure-sine wave output and high surge capacity, it handles compressor start-ups smoothly.

Key Specs & Features:

• 230/240 V AC output, suitable for standard appliances including inverter-style A/C units

• Internal DC fuse and multiple electronic protections (over-voltage, under-voltage, over-temperature, short-circuit) for safety

• 12 V DC input

 

Both are well suited to running an inverter-style caravan air conditioner. However, before you invest, it’s important to understand what this means for your battery bank. 

 

It's Math Time!

Now let’s discuss using the above power information and convert it into how many amp hours the air conditioner uses per hour. 

The formula for estimating current draw is:

(kWh ÷ system voltage) × 1,000 = Ah 

For example, if the FreshJet Pro draws an average of 1000W per hour, on a 12V system, that equals roughly 83 Amps.

Battery Capacity - 80% Discharge Capacity = Usable power in Ah (300 - 80% = 240ah) 

So, with a quality 300ah lithium deep-cycle battery, you could theoretically run the air conditioner for about 2.5 hours before needing to recharge (240Ah ÷ 83Ah = 2.89 hours). Solar panels play one of the biggest roles of staying off-grid for longer, if you don’t have enough solar to replenish your batteries you will have to head into town to recharge or head off on a drive to allow your tow vehicle to charge you battery bank.

Solar is calculated below in 2 steps:

 

Step 1 

Daily Wh = Panel Wattage x Peak Sun Hours x Performance Ratio
Daily Wh = 200w x 5h x 0.80 (average) 
Daily Wh = 800wh

 

Step 2

Daily Ah = Daily Wh
            System Voltage
Daily Ah = 800wh
            12v
Daily Ah = 66.67ah

 

So to put it simply a 200w panel in perfect conditions for 5 hours will yield about 66ah of power back into your battery bank. Now that we have covered what the air conditioners can draw and battery capacity and solar required, let’s look at some options to get you wired up!

 

Renogy 600Ah Off-Grid Adventure Bundle

This bundle has been designed to provide the perfect solution for offgrid caravaning. With a whopping 600ah of lithium this bundle will allow plenty of power to run your air conditioner whilst still providing plenty of capacity to keep up with your other appliances such as your fridges, fans and other electrical needs.

480Ah ÷ 83Ah = 5.78 hours of run time

Let’s talk about power replenishing as we know your battery system is only as good as the power you can put back in it.

 

Recharging Your Battery System

The Renogy 50A DC-DC Battery Charger with MPPT will need approximately 2.5 hours of driving to recharge two 300Ah batteries (600Ah total) if they have been fully depleted.

 

Solar Replenishment

• 5 hours × 800W = ~4000Wh

• After system losses, this equates to roughly 300Ah returned to your batteries

This is excellent for topping up but not enough to fully recharge a 600Ah system if it has been heavily used and you're staying stationary. That’s where portable solar helps.
A panel like the Renogy 400W Compact Mono Portable Folding Solar Panel can provide additional input, especially useful if you’re parked in partial shade or plan to stay put for several days.

 

Let's Talk Air Conditioners

Now we know our power needs let’s look at the range of Air Conditioners most suited to running off a battery system.

 

Dometic FreshJet 7 Series

The Dometic FreshJet 7 Series is a premium, energy-efficient rooftop air conditioner range ideal for modern caravanners.

Key Features:

• Compact rooftop footprint

• Dometic CleanAir filtration system 

• Adanced inverter compressor

• Cools up to 41% faster than previous models

• More energy efficient - perfect for off-grid use

 

Product Variants:

• FreshJet 7 Series Lite - for small vans and buses

• FreshJet 7 Series Pro - for vans up to 7m

• FreshJet Series Plus - for vans up to 8m

 

MyCOOLMAN 3000W Inverter Roof Top Air Conditioner

The MyCOOLMAN Roof Top Air Conditioner is another excellent choice for off-grid cooling

Key Features

• 3kW cooling capacity

• Designed for vans up to 7m

• Approx. 35kg total weight 

• Multiple airflow angles

• LED interior ambient lighting 

• Power draw similar to the FreshJet Pro

 

Let's Wrap It Up

Back to our original question — can you run your caravan air conditioner off your battery?
Yes, you can, and with the right setup it’s very achievable. There are also some key steps to help keep you cool this summer below.

 

• Helpful Tips to Beat the Heat This Summer:

• Use lithium batteries for higher current delivery and better usable capacity

• If you need shade, boost your portable solar power (check controller capacity first)

• Run your A/C for an hour after sunset to cool your van for bedtime

• Use the timer function on your remote so you don’t forget to turn it off!

• Avoid using high-draw appliances (air fryers, kettles, coffee machines) while cooling — compromise is key!

DISCLAIMER* Please note, this advice is general in nature and we strongly recommend consulting the product manual and where relevant, a professional installer.