6 12V upgrading tips

By: Michael Borg, Photography by: Matt Fehlberg

Borgy gets stuck into some 12V upgrades, and gives us a few handy hints for diagnosing electrical dramas.

12V Upgrading Tips

Well, one thing’s for sure, camper trailer owners and enthusiasts aren’t the kind to shy away from a bit of extra convenience or comfort in the bush. That’s probably why the addition of 12V gizmos has completely revolutionised the way we camp these days.

I mean heck, I like old-school, basic, bush-style camping just as much as the next bloke but, for some reason, my camper trailers and 4WDs are all littered with 12V accessories from front to back, inside and out!

In fact, that’s exactly what I’ve been up to in the shed lately; you know, tinkering with a few new 12V upgrades to share with you lot.

So put your feet up, grab a cuppa and read on, my friends...


If you’re planning to tow a camper trailer that’s equipped with 12V power, you’ll need to run a charging lead from your vehicle’s auxiliary battery to the rear of your vehicle. The idea being your vehicle can charge the trailer’s battery as you drive. It’s a pretty basic thing to do, but you will need to get a few things right.

Voltage drop will be your worst enemy, given the overall length of the charge wire, so it’s very important to get the size of the 12V cable right. I used 6 B&S cable which is rated to 130A; it’s about the standard cable size for this sort of job. As with any electrical wiring, you’ll need to install a fusible link as close to the battery as possible, and always ensure the wiring is wrapped in a protective layer and run well away from heat sources or vulnerable locations.

Finish the job off by fitting an Anderson Plug connection (rated appropriately) at the rear of the vehicle in a position that’s easy for the camper’s wiring harness to reach.


If you’re like me and always seem to get stuck in sticky predicaments, then a 12V winch can be a real Godsend. It’s even better if you can spare yourself the trouble of getting the controller’s cable tangled up every time you need to use the winch. So, to help overcome this problem, I decided to wire the winch controls to inside the cab. It’s a pretty easy mod to make but, to make it super simple, I decided to use the original winch control and wiring loom.

It’s literally as simple as running the original winch control cable from the solenoid box through the engine bay and up into a switch on the dash. You can pick up a pre-marked rocker style winch control switch from most major auto parts stores these days for about $20. It’s also a good idea to wire up a second switch to act as a cut-out switch for the winch controller, just to ensure you don’t accidently activate the winch while you’re driving; that could be a big problem! To do this, it’s literally as simple as wiring a toggle switch in-line with the constant power to the winch control switch as per the diagram.

12V Upgrading Tips 1


A buggered fridge can be a big problem in the wrong circumstances but, the truth is, if your fridge stops working there’s a better than average chance the problem lies in the wiring side of things and not the fridge itself. Let’s take a look at how to narrow the cause of the problem down shall we?

First up, if the fridge won’t turn on and the lights or display don’t activate, check the fuse isn’t blown, which cuts all power off to the fridge. If the fuse is okay, ensure there’s power at the fridge’s plug. If you don’t have a test light, try running the fridge using the 240V mains power option; if it works, you know the 12V wiring is likely to be buggered.

Most fridges are actually designed to shut off if the voltage gets too low in order to save your battery, so a fridge that turns on but shudders or turns off intermediately is usually a suffering from a lack of voltage. This can be caused by anything from a dirty electrical connection like a faulty merit plug to the electrical cable used being too thin for its length and current draw, which doesn’t allow for voltage drop.

If your fridge turns on and operates but doesn’t seem to work efficiently or stays on constantly, check the fridge has adequate ventilation and airflow around the vents.


Most electric water pumps these days are pressure activated. That basically means the pump will turn on when it senses the water pressure in the lines drop below a predetermined rate, like when you open the tap and let the water out. It’ll also turn back off once the water pressure returns to a certain rate as well.

A pump that activates on its own without you operating the tap usually indicates there’s a leak in your plumbing, which allows the water pressure to drop below the water pumps activation trigger point. So it’s always a good idea to have the pump isolated via a switch just in case you damage a water hose on the road and the pump decides to pump the remaining water in your tank out!

12V Upgrading Tips 2


Loose battery terminals are one of the leading causes of electrical failures on a camper trailer or 4WD. But there are literally dozens of bush mechanic fixes that will help tighten them up and get you out of trouble as a temporary solution.

First up, try wedging a strip of a soft drink can around the battery pole before wriggling the terminal over the top. The idea being it acts like a shim to help tighten it up!

Another option is to wind a self-tapping screw down between the battery pole and the terminal, once again to shim it up so the terminal can clamp up properly.

For loose crimp terminals, the fix is usually as simple as squeezing the female connector down onto the male terminal with pliers and/or soldering the join or terminal.

charge up YOUR LIFE

While camping isn’t about electrical gadgets there’s definitely a certain degree of satisfaction achieved when your 12V gear works perfectly. This is especially true when you end up adding a few flash upgrades that are a bit fancy and even more convenient. So if you’ve got a few unique ideas, and don’t mind getting your hands are a bit dirty, why not have a go at a few 12V upgrades? Chances are, you’ll absolutely love it!

Check out the full feature in issue #105 August 2016 of Camper Trailer Australia magazine. Subscribe today for all the latest camper trailer news, reviews and travel inspiration.