Power, in particular for long stay trips is an import consideration in your planning. Don’t get me wrong power is not essential, but if you like a nice cold beer then hear me out 🙂

With a good dual battery setup the rig you’re sitting in is the by far the best power generator you’ll ever take on your trip with you, but it’s not perfect…

Say for example you want to set up camp for a week and chill out by that river. You don’t want to leave your car running for half the day to keep your auxiliary battery charged and fridge running.

As an offroader that really leaves you with two options.

  1. A stationary generator that will do essentially what your alternator is doing in your car only with it’s own engine.
  2. Use the power of the sun to keep your batteries charged.

There are some key pros and cons of these two options:


  • Pro: Reliable and simple
  • Con: Only works during the day


  • Pro: Works when you need it
  • Con: It’s an engine, so can break down, makes noise and needs fuel.

They both cost money too 🙂

The truth is, I actually carry both. I have a small generator and a decent solar system that gives me the best of both worlds. As my solar panels were a much bigger investment for me, today I want to share what I learnt, how chose I and setup my solar power generation source.

Going solar…

As I live in Australia we have lots of sun most of the year. Solar as a secondary source of power is a logical choice. In terms of my needs, I actually don’t have a heap. Our fridge is the biggest guzzler of energy, outside of that it’s just running a few LED lights, keeping the tunes cranking, and charging all our various iThingies.

Storage Capacity:

When I’m out in the bush I’ll either just have the cruiser, or the cruiser + our camper trailer. The batteries we have are:

  • LandCrusier: 1X starter battery, 1 X 100 amp hour auxiliary battery (isolated)
  • Camper: 2X 100 amp hour auxiliary batteries

So when the camper is connected to the cruiser I have a decent 300 amp hours worth of charge, which is enough to run the fridge for a long time! But I’m not a guy that likes to leave things to chance…

When starting my solar panel research I quickly realised a couple of things.

There are a two different types of 4×4 and caravan solar panels:

Polycrystalline: These units are more what’s described as your trickle charger. They charge at low voltages. There are awesome in that they work in low light conditions but these systems are designed to stop your battery going flat, they won’t charge them. That doesn’t make them a waste of time, I have one of these keeping all the batteries for the toys in the shed working, but that’s it. They are also the cheapest, so make sure you know what type of panels you are paying for.

Monocrystalline: These are what you should be looking for as an offroader. They’ll charge with a lot more gusto (12 volts and up). They and do require more of the suns rays but these are the types of panels that will actually re-charge your battery like an alternator or generator.

Polycrystalline is cheaper than Monocrystalline so don’t get caught out buying the wrong one because it’s cheaper — chances are good it will be a complete waste of money.

The type of solar panel is one important consideration but there is another — a regulator. This little device stops overcharging your battery with a high a voltage (when the sun is really cranking!). Also If you’re battery is full and the sun is still shining it will stop the charge. These regulators can either be purchased independently, come part of a solar ‘kit’ or part of the isolator on your dual batter system.

Don’t go solar charging without one.

Size matters

There are two key measures of the output of your solar panel. Wattage and Voltage. As I’ve already mentioned, you want a Monocrystalline type panel that produces a 12volt + charge with a regulator. The second is wattage, and when thinking about ‘how big do I need’ there’s a bit of maths to do. I made this handy little calculator to help…

12v solar power calculator

*note the runtime of your fridge isn’t 24 hours, its the time it is actually cooling.  Use 12 hours if you are unsure.

Thank you for your submission!

The panel fit out

So once you’ve determined the size you need, it’s time to think about how you’re going to fit the thing. I like flexibility with anything I fit to my rig so I opted for a unit that folds up into a neat carry bag with the the regulator and leads all part of the package. I also like that it has it’s own stand so I can put and point the panels where every is most optimal. The downside to this is that when I’m moving it’s packed away, but then my alternator is charging my batteries in that case anyway.

The permanently mounted systems on the roofs of rigs and campers are good, just not for me. All I needed was an 80 Watt system which I picked up from here.

I then created two Anderson plug connections. 1 on my cruiser that connects to my Auxiliary battery under my bonnet, the second mounted to my camper that connects to the twin deep cycle batteries. This way I can charge in any scenario. See below.


  • When I want to charge the camper batteries from the car alternator I connect the car plug to trailer plug.
  • When I want to solar charge the car I connect the panel to the car plug
  • When I want to charge the batteries in the camper I connect to the trailer plug.

Easy peasy.

So that’s the solar system I have in my rig. It’s keep those beers cold in event the hottest situations. I hope it gives you some info to help figure out what’s best for you.

Any feedback or thoughts or different setups that have worked for you, feel free to let me know in the comments.