Real Life 12V Setups

David Gilchrist — 20 May 2015

When it comes to caravanning, most of us simply can’t go far without electricity. While you might choose to run your caravan fridge off gas when you’re not plugged in at a caravan park, the need to keep the remainder of your devices sparking means you need to keep your 12V battery charged. We asked some caravanners how they tackle the task…


‘Solar’ Mick and Valarie Piper tour the outback in their customised six-wheeler Toyota LandCruiser dual cab truck towing a Lotus caravan.

For Mick, getting out and about in the great outdoors doesn’t mean having to go without life’s electronic conveniences, such as enough lighting, television, or the ability to run his assortment of fridges and to keep his electronic devices fully charged.

Depending on the destination, Mick runs up to four fridges spread between his truck and caravan; the only fridge Mick doesn’t run off his auxiliary batteries is the main fridge inside his caravan. He runs that off gas. He says that’s because a typical caravan fridge draws too many amps to sustain it reliably off an auxiliary battery system.

Mick’s power recipe includes a whopping 550W of solar on his caravan roof, split between two 190W panels and two 85W panels. He then musters another 120W from a solar panel on top of his truck. Those panels feed three auxiliary batteries in his truck and three in the caravan. But that’s not the end of it.

“I also run a CTek 250S system, which manages the batteries, and I have just put in a 1000W inverter in my truck with a 24V, 10A fuse so that if I get a surge, it doesn’t blow my inverter up,” Mick said.

The CTek system optimises battery life and charges Mick’s batteries using his truck’s alternator, solar power or both. It adjusts the charging voltage and current according to the state of charge and temperature of his auxiliary batteries – reducing the time required for them to charge.

Mick also employs a 1000W pure sine wave inverter, which means he has the sort of clean power to reliably run his television and computer as it converts his batteries’ direct current into alternating current and raises the voltage to 240V.

Mick’s inverter size means he’s probably able to convert up to 1000W DC into AC current in a single hit. Put simply, he’s got plenty of electrical grunt to cover the 60L, 45L and 15L fridges he often runs from his truck.


Sue and Tony Stephenson from Brisbane are enthusiastic caravanners who love the simple life that caravanning brings them. Sue and Tony keep their Jayco caravan powered with a very simple system using just two 64W Uni-solar panels.

These panels do the heavy lifting for Sue and Tony as the panels actually split visible light into red, green and blue light in three distinct layers, with each designed to process each primary colour into electricity. The argument is that this makes the panel more efficient.

Those panels then charge two 120Ah batteries via a regulator, giving the couple enough power for their lights and a single portable fridge.

Both Tony and Solar Mick said that while you might only rarely run out of power, it is worth having a back-up portable generator. When needed, Tony uses a tiny 1kVA generator. He said, given his needs were mostly meet by solar technology, the small generator was adequate as a back-up.


Mike and Joan Maciljewski started caravanning in 1982 in a Newlands 16-footer which was ‘built like a box and towed like a block of flats’. Mike summed up the Newlands’ power arrangement in one word: nil.

These days, the Maciljewskis are proud Jayco owners and travel with twin batteries in their van. Mike said he generates power from solar panels on the roof, connected to twin batteries installed under the dinette. With that setup, Mike said they could run everything except air-conditioning and the microwave.

Mike and Joan upgraded their Jayco’s system by adding solar. “This model came with one battery with one 60A fuse coming out of it to do just about everything,” Mike said.

“I’ve put in additional switches so I can switch off all sorts of things and there is a now a multiple fuse bank so that virtually everything goes through a double safety system by going through a self-resetting circuit breaker and then a fuse.”

Mike’s system incorporates two 90W solar panels charging two 100Ah AGM deep-cycle batteries, boosted by an Optima battery in the back of their Colorado ute.

The Optima hybrid-style battery in the ute is able to be used as a cranking battery and as a deep-cycle battery. A hybrid-style battery can bounce back from deep energy drains to full energy capacity and power ample electronic bits and bobs while still managing to start their tow vehicle.

The Colorado’s setup starts with Redarc solenoids connected to the car battery. The solenoid goes via a 12mm wire to the rear Optima battery, which has a marine-grade switch to isolate it from the car battery. That battery has its own voltage meter to show the true state of its charge.

Mike said the best advice he could ever offer anyone looking at improving their charging system is to know what your electrical needs were and plan to meet them; don’t over spend. “Try and match the amps in your battery with the watts on your roof,” he said.


Ralf Brosch from Queensland manufacturer Free Spirit Caravans said the electrical arrangement you install depended on your needs.

Supplying your power needs and keeping your batteries charged depends on your circumstances, your day-to-day use and how much amperage you have to cover.

For Ralf’s money, he said a roof-top solar panels that provided 300W, was the minimum. That equation changes, however, if you use lighter but less efficient flexible solar panels or rigid panels. “Combine those with lithium batteries and you will find they charge quicker and hold power for longer than normal deep-cycle batteries,” he said.

However, Ralf said that the future in battery charging technology was interesting, with ever-changing technology like spray-on solar films, solar resins embedded in surface paints or nano-technology potentially all coming into the battery charging mix – recharging the entire problem.

The full feature appeared in Caravan World #536 April 2015.


12v battery Toyota LandCruiser caravan Lotus Newlands 16-footer Jayco Free Spirit Caravans


David Gilchrist