Off grid solar
The dream of camping in remote areas and not compromising on luxury is within reach of most Australians wanting to explore Australia with solar.
Many caravans come with a solar panel or 2 and a solar controller which charges a battery during the day using the sun via the solar panels and when connected to 240v power can be charged using the battery management system.
Most caravan lights are now 12-volt only so they run from the batteries and the batteries get recharged giving you power for the night when lights will be needed.
Best solar controller?
There are 2 main types of battery management systems:
MPPT (Maximum Power Point Tracking)
PWM (Pulse Width Modulation)
The Redarc power management system is an example of a DC-DC charger. It can recharge many different battery types, either from 240v mains power, the DC charge coming from the alternator of your vehicle or via solar panels that can be connected to the controller using MPPT technology. There is even an option that has a 2000W invertor to be able to plug in any mains powered device.
Best solar battery?
There are 2 main types of solar batteries for use when on the road or living off the grid:
Lead acid.
Lithium-ion.
Lead acid batteries are relatively cheap and they are heavy.
Lithium-ion batteries are very light compared to Lead Acid batteries. These are what you can find in a Tesla Powerwall, and most mobile phones and are the industry go to for many new devices for battery storage.
What I did
When setting up my 4WD I decided on 2 house panels (190W each) that a friend gave to me and an MPPT controller.
I chose the MPPT controller as it is a more efficient way to convert solar energy to charge a battery.
They do cost a little more than a PVM-style controller and in my opinion, worth the money.
I mounted the panels on the roof of my Patrol using my roof racks.
When I first was setting this up, I used 3 lead acid batteries (390 AH in total) and connected a 240V invertor. This allowed me to run a 40-litre, 12-volt fridge 24×7. This setup also provided enough power to connect the coffee machine to the invertor (3000W) and make a cup of coffee on the side of the road every day. This was proven when travelling up Cape York when there was no option to connect to power and day after day, we were able to enjoy a cup of hot coffee and the hot milk from the milk frother without the need to be connected to an electrical mains socket.
I also have a 200A safety switch which will cut the power to the inverter if the current goes above 200A.
I have since replaced the Lead acid batteries with a Lithium-ion battery with 200AH capacity. I have also replaced the 40L fridge with an 80L split zone fridge/freezer. I am finding that even though the usable capacity is very similar to my lead acid setup, the lithium-ion battery is getting completely drained the fridge turns off and I am unable to run the coffee machine every day. When looking further into this I can see that the current drawn from the lithium battery is shown to be rated to 150A with a peak current draw of 300A for no more than 15 seconds. When I look at the current requirements to run the coffee machine, I need 1875W which when I divide 1875W by 12v I get a current draw of 164A. This should all be within the limits of the system.