Upping Your Off-grid Power

Steve Cassano — 15 November 2018

When we’re at home, we expect everything to work efficiently and easily, particularly when it comes to electrical devices. Perhaps we’re a little spoilt by the constant improvements in cameras, computers, tablets, gadgets and other household regulars that go on making life easier and easier. We flick the switch and demand the little green LED to show we have clean power.

These high expectations can stick by us adventurers and campers when we head out exploring, especially when we have kids in tow. Of course, some of us prefer to basic camp, carrying no more than waterproof matches and a sheet of canvas – but that’s a story for another day. 

Today, let’s talk about matching your setup to demand for watts.


Many modern vehicles and camper trailers come fitted with an array of electrical outlets, such as cigarette or USB ports. These allow you to run or charge your 12V-based devices. If you’re lucky, your 4WD might even be equipped with a 240V outlet for those times when charging via USB does not suffice. Unfortunately, many of these fitted 240V outlets have a limited capacity of around 150 watts.

In my experience, using a cigarette outlet is satisfactory for many devices, whereas USB outlets are slow to charge a device’s battery – especially in times of need, when the battery is low. Most fitted USB outlets are maxed out around a couple of amps at best.

Alternatively, the device itself may be responsible for the difficulty; some accessories and brown goods from home such as televisions, radios, computers, tools and apparatuses have no direct 12V option to run. 

Sometimes, there is no real substitute for clean and efficient 240V power – or is there?


To attain 240V power similar to home, you’ll need an inverter. An inverter basically converts the 12V power supplied from your vehicle’s battery to 240V. However, as with many things, it’s not as simple as buying the cheapest option and hoping everything will work out. There are a number of things to consider, such as: the amount of simultaneous watts you require, the location (you need good ventilation in a dry clean environment), distance from your battery and how you will securely mount it. 

Inverters range from about 150 watts to in excess of 3000 watts; based on my requirements, a 700 watt inverter would suffice. I suggest you allow for a 20 per cent buffer, to cover any difference between actual and quoted wattage for devices.

For my travels, I needed to ensure I received the purest power, in order to protect sensitive equipment such as the computer and to guarantee appliances such as the microwave ran smoothly with minimal electrical noises. 


I chose a REDARC 700W Pure Sine Wave Inverter. Unlike the cheaper modified sine inverters commonly available, REDARC’s range is all pure sine wave, using more sophisticated technology to eliminate any possible damage to appliances. Why risk it?

I’d had great success with REDARC products so far and my initial impression was excellent. The easily recognisable red colour of the brand, along with its two year warranty, warmed me to the product immediately. The quality of construction was evident; weighing just 2.6kg, the inverter’s compact body is encased in tough steel and plastic with robust connections, plus sturdy mounting points.

The REDARC 700W inverter came packaged with an easy to follow user manual. However, I was a little surprised no cabling was included; however, this is probably because everyone’s setup is unique. A quick reference to the user manual (and of course Dr Google) revealed that to prevent voltage drop and ensure peak performance, I should use twin 2 AWG cable (also similar to B&S and rated to approximately 250 amps) to cover, in my case, 3.5 metres; like many 4WDs, my auxiliary battery is located under the hood and I prefer to have the inverter in the cargo area. To protect against any electrical gremlins, I used an inline 125amp midi fuse and holder. The cable, fuse and holder, plus the 50mm terminal lugs, cost me around $140.

In under an hour, using cutters, a hex crimping tool and some heat shrink, the cable was complete. 

Like all things electrical, treat the installation with respect. Just like at home, you’re working with high voltages. Read the manual thoroughly, focusing on the highlighted warnings; do your research and follow proper electrical practices including clean tight fittings, protection of the unit and cabling, and reference to an auto electrician if in any doubt.  I also advise leaving the fuse out until the last minute to protect against any short circuiting during installation.

After weaving the cable through the vehicle and securing it, the inverter was ready to use. It’s worth keeping the manual on hand for future reference, because this REDARC inverter comes with status and safety features incorporated via the use of LED lighting. 

Also, remember that the higher the amp hour rating on your battery, the longer the battery will last. Use the formula Amp = Watts/10. It is the actual watts load that counts, not the inverter rating. Don’t think you can endlessly use an inverter unless you have a large battery bank or a means to top your power storage – which brings me to my next segment.


The alternator in your 4WD is designed to charge the battery and power the vehicle’s  electrical requirements when the engine is running. For the most part, this source of power is adequate to keep things humming along nicely, but what happens when you pull into camp and the engine is not running?

This is where solar options come in handy. I don’t currently have a large auxiliary battery in my 4WD, so ensuring that I maximise battery life is important.

Solar panels are available as a fixed, folding or blanket style. For those who drive a medium sized 4WD, like myself, minimising weight and maximising space is a priority. Therefore, the obvious choice for me was blanket style. 

Given I had recently chosen the REDARC inverter and already had a REDARC BCDC1225D charger with a built-in solar regulator, I again trusted REDARC to produce the goods.

I selected one of their 115W solar blankets, which punches up to 115 watts, weighs just 4.5kg (half the weight of an equivalent hard panel) and is the size of two stacked laptops.

The REDARC solar blanket comes with no more than a carry bag and a very easy to follow user manual with several diagrams to illustrate various points and setups. There is an affixed Anderson plug located on the rear of the blanket, but no solar regulator supplied. At first I wondered why this was missing, because many others include this as standard. It soon dawned on me that, like with the inverter, people have different setups and it’s pointless to provide something that won’t suit the user. 


Whilst REDARC encourages users to connect their solar blankets to one of their BCDC chargers with a built-in solar regulator, it’s quite easy and acceptable to use an independent 20amp solar regulator. After all, many people don’t have in-car chargers with built-in solar regulators, yet they still wish to take advantage of solar. 

You’ll also need fused twin core cable rated minimum 6AWG with an Anderson plug and a means to attach to the battery at one end. Don’t bother with cable any less than five metres; anything shorter than that is too restrictive.

I opted for one of REDARC’s Cable Value Packs SRPA20-VP, allowing full flexibility to manage any situation. It includes a 20amp solar regulator, five metres of twin core cable and a 1.5m cable with battery chips and an inline fuse. 

I liked this well made package, especially the unique style of regulator in a sealed metal casing with twin built-in Anderson plugs (no lugs or hex screws in sight) and a mounting point. Along with the regulator, all the cables and connections are water and dust resistant.

Many of the cheaper options on the market, including a majority of fixed panels, attach solar regulators at the rear of the panel or blanket for convenience. It’s my understanding that this is not ideal, due to the generated heat from them being in the sun. It’s better to have the solar regulator closer to the battery to keep it cool and minimise voltage drop, as you can achieve with the REDARC 115w solar blanket.

This value package can be found for under $250; whilst it is not mandatory with my BCDC1225D charger, I believe it’s a must because of its versatility. It allows you to efficiently charge any battery – this of course includes the battery of the beer fridge!


At this point, you’d think it’d be all rosy and it mostly is, except for one thing. The fold-out blanket is a hassle to manage and angle towards the sun to maximise exposure. The placement of the blanket took me several trials to work out what was best. As can be seen in the images, the bonnet and roof were good choices. So was jamming a couple of straps into the door frame, so the blanket hung on the door. Still, it’s very challenging to get that perfect 90 degree angle to maximise efficiency.

When testing the blanket, I was able to view the wattage and amps the solar blanket actually produced, using a wattage meter which I sourced online for around $15. The results were impressive – even in partial sun and at various angles.

When laid flat in October’s late morning sun, the watt meter showed that the blanket peaked at 5.22 amps, just short of the claimed 5.8 amps – not bad since there was a hint of wispy cloud. As soon as the cloud thickened, the amps dropped quite a bit but still the blanket’s efficiency prevailed.

Hanging the blanket vertically, although convenient, didn’t produce the same output as on the roof. However, it still produced a credible 3.06 amps. Of course, these measurements are just a guide, not an exact scientific result, given the inexpensive watt meter being used.


I really like the REDARC products; they’re well-made, compact, robust, efficient and look the goods when you hold them in your hands. I was impressed with the solar blanket’s output, even in moderate conditions. The brand’s excellent after-sales service and two year warranty is very assuring.

If you have a well designed electrical system – including a dual battery system plus an inverter paired with solar options – you will be able to stay out in the bush for longer, without the fear of your electronics failing you. A bit of forethought and investment can bring your camping setup a step closer to the ease you experience at home. 


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