Hybrid Energy Systems with Lithium Batteries in Off-Road Caravan

Posted by Bruce Loxton

Mar 4, 2014 3:25:00 PM

offroad caravan hybrid power of 12V with 240V air conditioningMore than 10 years ago, portable generators introduced mobile power for off-road caravans. Overnight, this changed the comfort level with the ability to run air-conditioners in particular. Now there is an incredible step change again: 240V air-conditioners operated from lithium batteries.

In it's 20 year, Kimberley Kampers celebrates this milestone with another first in Australia and possible the world!

Portable generators, whilst compact, are still noisy, heavy to lift in and out and require carrying petrol on board. This is a safety issue and in some Indigenous areas, travel permits prohibit petrol containers.

If the air-conditioner is in excess of 2.5kW, it will most likely need a 2kW or 2.5kW inverter generator. These weigh 25kgs+ and use up to 10 litres a day of petrol.

Technology has now brought another step change. There is no longer the need to carry large and heavy generators. Hybrid Energy systems use smaller generators and take their power boost from lithium batteries charged by the available  solar energy. 

hybrid energy lightweight off road caravansThe issue with air-conditioners is that when running, they only use around 1kW of power. However, at startup they use a surge of power for less than 2 seconds. So for that pesky 2 second surge, the customer has to buy a generator at least twice the size and create more noise and use more fuel.

Hybrid Energy Systems are a new version of Inverters that pull that additional "boost power" from the batteries for the 2 seconds during start up and leave the air-conditioner either running on a smaller generator or running on battery power for the rest of the time.

The current loads here during startup are huge at greater than 420Amps on the 12V Lithium Battery system. This means that the Hybrid Energy control can only be used with Lithium Batteries.

To the user, it is very simple and the boost power happens automatically.

The photos below from our Test screen shows 383 Amps being drawn in start up mode (hard to catch the peak on camera!)


The Second screen photo on the right shows the steady state 86 Amps being used when the batteries only are running the airconditioner.

High Current Start up with 240V air-con from 12V lithium batteryBattery only running state with 240V airconditioner start up in kimberley eco suite











hybrid running state with 240V airconditioner start up in kimberley eco suiteThen running in Hybrid Mode with the 1 kVa Generator and the Lithium Batteries operating a 2.2kW Split Airconditioner.

You can see:

  • 1040VA (approx 1kW) of power coming in from the generator
  • 1060VA (approx 1 kW) of power to the air-conditioner
  • 16 Amps of power coming from the batteries to make up the difference between the generator output and the air-conditioning demand.

off-road caravans with touch screen technology just like a smartphoneSmart Touch Display on the Kimberley off-road caravan range shows important battery and current load information. With this easy ability to determine the amount of battery capacity left, it is easy to have confidence in the Hybrid Energy system. There are individual current and "power capacity" sensors on the batteries, on the inverter and on the solar system.

The photo on the right shows the system in the Kimberley Karavan.


off road caravan air conditioningThere is a big advantage of using this with a split air-conditioning system. In a "Split" system, just like the new air-conditioning technology in most new homes, the compressor is located outside the "caravan". In the case of the Kimberley Karavan, the compressor is in the separate front storage pak. In the Kimberley kruiser, it is located in the front Uni-pod and in the Kimberley Kamper, it is located in the Delta Gullwing Pak. This significantly reduces the noise inside as well as reducing the travel height and storage height of the Karavan.

Combined with a smaller remote generator, the noise at night is considerably reduced. In fact with no generator, it is very quiet inside for a good night's rest!



off-road caravan hybrid energy system inverterThe Hybrid Energy Components are:

  • Batteries: 480 Ahr Lithium
  • Inverter: 3kW continuous, 5kW surge
  • Solar Capacity: 500W inKimberley Eco-suite, 720W in Kimberley Kruiser

The Lithium Batteries are re-charged from the solar panels on top of the caravan. A large solar capacity is needed.

Watch video clip below of the Hybrid system in action:


Photo shows an installation in a Kimberley Eco-suite:

For more information about High Capacity energy systems in off-road caravans download this FREE eBook:

For more information about off-road caravan design download this FREE eBook:

Essential Guide to design  of Off-Road Caravans Download Free eBook Here

Bruce Loxton


Topics: off-road caravan, lithium batteries, super thin solar panels, 12V airconditioning, light weight off-road caravans, flexible solar panels, hybrid energy

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The Kimberley Karavan, a lightweight folding off road caravan that can go anywhere. Kimberley Karavans are unique with their internal shower and toilet, comfortable internal seating and luxury finishes.