12V Guru – Simple 12V Power System for Travelling Big Lap

Question to 12V Guru: Planning  a Big Lap, need a simple 12V power system setup

G’day David,

Thank you for your on-going expert advice.

I’m planning a 5 month ‘Big Lap’ and my off the grid camping is likely to be limited to a couple of days at a time in a free camping site. Do I buy a caravan with additional solar panels and batteries or do I cut my costs, get a single solar panel and battery and a decent generator?

I’ve been told that a single solar panel and battery is more than sufficient for a few days but will negate the use of A/C and the microwave and adding an additional panel and battery adds more weight than a generator.

Notwithstanding this, my car is a diesel, so I will then have to carry additional petrol for my generator, or do I plug for the more expensive diesel generator? My gut feel is single solar panel and battery, with a petrol generator. I would appreciate your views.

Kind regards,


12V Guru answers:

Hi Clark,

Congratulations on taking the plunge and spending 5 months on the road doing the ‘Big Lap’ – many lifetime memories coming your way.  In our experience most ‘Big Lappers’ tend to follow the warmer weather which means you are likely to be in QLD/NT area during the traditional June-Aug (thereabouts) winter months and then heading south as the weather starts to either turn too tropical and wet up north and becomes pleasant down south.  In this case you are more likely to be following a route that has plenty of natural sunlight indicating that solar is going to be the way to go.

Simple 12V power system -single 100Ahr battery, single solar panel and a generator

In my experience I would suggest that if your camping off grid is limited to a couple of days at a time then your proposition of single panel, single 100Ahr battery and a generator for a simple 12V power system would be adequate. 

solar panels – fixed or portable?

I would suggest that regarding the solar panel that you look at the portable folding panel option. There are heaps of options out there and remember you get what you pay for.  If it looks too cheap than you will probably find it is poorly made and will not stand the rigours of 5 months on the road without being wrapped in cotton wool.  Most will come in a storage bag of some description.

Suggest the portable panels instead of fixed roof mount as they are more flexible in being able to place strategically to harness the sun.  We all prefer a bit of shade for our van when overnighting in the warmer months so if after finding that prize shaded spot you then need to give it up to position the van roof in the hot sun not happy! Warms the van up too much! Park with shade and use portable panels.

Required features of the solar panels

Two key things to look for: firstly – quality of build. Hinged in the middle with a sturdy aluminium frame, heavy suitable cable properly terminated with Anderson connectors or similar – stay away from alligator clips. Kids trip on the cable, pulling it out creating electrical hazard. The frame legs need to be adjustable so that during the day the angle of the panels can change to maximise the ability of the panels to generate power.

Secondly, suggest that you look at panels which have the solar regulator mounted to the back of the panel and the ability to connect either with or without solar regulator.  A lot of power management systems these days like the BMPRO J35 Jayco series enable you to connect directly to the power management system and achieve a better result in charging your battery faster than a standard PWM cheap regulator – gives you options.

12V battery options

Your choices for batteries are endless also. Again, would suggest looking at a quality battery which has a good warranty and the ability to have it replaced Australia wide should it fail. Lead acid batteries whilst less complex than the more expensive Lithium options are unfortunately in a sealed black case and there is no way of really knowing what is happening inside should a cell collapse. 

The ability to be able to take it to a designated battery service location to have it tested around the country counts is gold.  Buy a decent brand. Do not skimp on this part of the system as without the battery you have zero stored energy.  Would imagine you don’t wish to be running the generator full time.

Options for generator

The options for generators are relatively straight forward – buy an inverter generator which provides a clean electrical output, they are efficient to run (a small 5L container of petrol will cover a few days to top up batteries or run the microwave for 10 minutes) and certainly safe for charging electrical devices directly. Briggs & Stratton or Honda are amongst some of the very reputable brands out there. A 2kW or up to 3.5kW would serve your needs very easily.

Enjoy ‘The Big Lap’ with simple yet reliable 12V power system,

Yours, 12V Guru

The article was written for Caravan World Magazine.

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