There is a particular kind of silence you only get on a still morning at a free camp on the Hay Plain. No generator. No pump house. No interstate truck rumble. Just a kettle warming on a butane stove, the soft tick of a 12V fridge cycling, and somewhere on the bonnet of the 4WD, a folding solar mat catching first light. That mat, more than the awning or the diesel heater or the rooftop box, is what makes the whole trip possible.
At Outbax, we’ve spent the better part of a decade testing, fitting, and at times, breaking 12V solar gear on Australian caravans and camper trailers. What follows is the conversation we wish every customer had before walking into a 12V shop with a vague plan and a maxed credit card. It’s the same conversation we have with Outbax customers most days of the week—in a country with more sun than almost anywhere on Earth, and, frustratingly, an abundance of bad advice about how to use it.
This is not the marketing version. It is the version that explains why the 100W solar panel you saw on special is probably wrong for your van, why your factory AGM battery is the bottleneck most people miss, and why a 200W folding mat will, on a 40°C day in Mildura, deliver nowhere near 200W, no matter what the box says.
VoltX 12V 130W Fixed Solar Panel
Start with the Fridge, Not the Panel
The honest answer to the question: how much solar do I need? It depends on your fridge.
A 60 to 80 litre 12V compressor fridge is the single biggest power draw in most Australian caravans. On a typical day in fair weather, it will pull between 30 and 50 amp-hours from your battery. Add LED lights, phone, and laptop charging, a 12V fan on hot nights, perhaps a Starlink Mini if you are working from the road, and you are looking at a daily energy budget in the range of 50 to 90 amp-hours, or roughly 600 to 1100 watt-hours.
That is the number that matters. Forget the panel rating on the box for a moment. The question is whether your panels, under real conditions, can put back into your battery what your appliances take out, ideally with enough headroom to top up after a cloudy day.
A 200W folding solar mat in good Australian sun, properly oriented and unshaded, will produce somewhere between 60 and 100 amp hours over a clear day at 12V. Note the gap between the spec sheet and the field result. Panels are tested at 25°C cell temperature and 1000 watts per square metre of irradiance, conditions that exist almost nowhere in the Australian summer. By the time you account for heat derating, cable losses, charge controller efficiency, and the angle of the sun, real-world output of a 200W panel typically lands at 130W to 160W at midday on a hot summer day in Queensland or northern New South Wales.
For most weekend caravanners running a fridge, lights, and devices, a 200W folding mat paired with a 100Ah lithium battery is a sensible starting point. For full-timers doing the big lap, with a larger fridge, an inverter for the kettle, and laptops on most days, plan for 300 to 400W of solar and at least 200Ah of lithium. For 4WD camper trailer owners going remote and parking under trees most afternoons, redundancy matters more than peak output, which usually means a portable mat plus a smaller fixed panel rather than a single big array.
The Mistake Nobody Warns You About: The Factory Battery
Walk through any caravan park in Australia at six in the morning, and you will see a familiar sight. Lights flickering. Fridges ticking unhappily. Someone in a bucket hat fiddling with a battery monitor that reads 11.4 volts. The instinct is to blame the panels, but in our experience, nine times out of ten, the bottleneck is not the panel. It is the factory AGM battery.
A 100 amp-hour AGM battery is, in real terms, a 50 amp-hour battery.
AGM chemistry does not like being discharged below about 50 per cent of charge if you want it to last more than a year or two. So that 80 amp-hour overnight fridge draw you are running through a brand new factory AGM is shortening the battery's life every single night.
A 100 amp-hour LiFePO4 (lithium iron phosphate) battery is, in real terms, closer to a 90 amp-hour battery, because lithium tolerates much deeper discharge cycles. It also weighs about a third as much, charges roughly twice as fast, and lasts three to five times as many cycles. The maths on lithium for serious off-grid use stopped being controversial around 2022, when prices fell to the point that the cost per usable amp-hour over the battery's lifetime undercut AGM by a clear margin.
There are still cases where AGM makes sense. If your van rarely leaves powered sites, if you only camp a handful of nights a year, or if you live somewhere very cold and store the van outdoors in winter without a heated battery box, AGM is the simpler choice. For everyone else who is reading this article because they actually plan to use solar in anger, lithium is now the default.
VoltX 12V 100W Fixed Solar Panel Black Frame
Panel Types, In Plain English
There are essentially three families of solar panels an Australian caravanner will encounter, and each has a sensible use case.
Folding solar mats, sometimes called blankets, are the dominant choice for caravan and camper users. A mat like the VoltX 12V 200W Folding Solar Mat sets up in under five minutes, follows the sun by being moved every couple of hours, packs flat into a padded bag and stows under a bed or in a slide-out drawer when not in use. They are the most flexible choice and, for that reason, the most popular with grey nomads who park where the shade is and bring the sun to themselves. Their downside is that they are a piece of gear to set up, take down, and remember not to leave behind at the campsite. They are also the panel type most likely to be stolen, although in practice, this is rare in remote camps.
Here's what one of our customers said:
“Ordered it on Monday and it arrived two days later on Wednesday. Very quick service. Hooked it up to a Redarc DCDC charger, and it's working a treat charging my VoltX Slimline 100 Amp battery. Very impressed with it and the prompt delivery. My only regret is that in the rush to place the order, I forgot to use the code to cut the price in half. My bad, but still very happy with the product.”
Flexible thin film panels, such as the VoltX 12V 100W Flexible Solar Panel, are designed for permanent installation on curved van and camper roofs, especially pop top vans, slide-on campers, and motorhome cabovers where weight and silhouette matter. They are perhaps a tenth the weight of a glass-framed rigid panel of the same wattage, will not crack if a tree branch hits them, and can be siliconed directly to the roof without brackets. They are also less efficient per square metre than rigid panels, run hotter (which derates output further), and have a shorter service life under harsh UV.
Rigid roof-mounted panels are the workhorse of the touring fleet. Glass-faced, aluminium-framed, and professionally installed on rails or brackets, they offer the best output per dollar and the longest service life. They suit touring caravans that move every few days and park in the open. Their drawback in Australian conditions is shade. A single overhanging branch on a 200W rooftop panel can knock its output to almost nothing, and the conventional wisdom that you should never park in the shade is, in 40°C summer heat, dangerously bad advice for both your panels and the rest of your van.
| Panel type | Setup time | Output stability | Best for | Outbax SKU example |
|---|---|---|---|---|
| Folding solar mat | 3 to 5 minutes | Excellent (you can chase the sun) | Caravanners, big lappers, anyone who values flexibility | VoltX 12V 200W Folding Solar Mat |
| Flexible thin film | One off install | Good on flat roofs, poor in shade | Pop tops, slide-ons, motorhomes, hybrids | VoltX 12V 100W Flexible Solar Panel |
| Rigid roof-mounted | Professional install | Highest output, sensitive to shade | Touring vans that park in open sun | Outbax rigid panel range |
The honest recommendation for most readers of this article is a 200W folding mat as the primary panel, with a smaller fixed panel on the roof as an always-on trickle for keeping the battery topped up while driving and while parked. That dual approach is what most of our experienced touring customers gravitate to after their first trip with a single-panel system.
VoltX 12V 200W Folding Solar Mat ETFE
MPPT vs PWM: The Unsexy Decision That Matters
Between your panel and your battery sits a charge controller. It is the bit of kit nobody photographs for the Instagram caption, and it is also the bit that determines whether you actually get the power you paid for.
There are two technologies. PWM (pulse width modulation) is older, cheaper, and works by clamping the panel's voltage down to whatever the battery is at. MPPT (maximum power point tracking) is newer, more expensive, and uses electronic conversion to extract every available watt from the panel regardless of voltage mismatch. In rough terms, on a hot day with a partially shaded panel, an MPPT controller will deliver 20 to 30 per cent more usable charge than a PWM controller of the same nominal rating.
For any modern Australian setup with a panel of 100W or more and a lithium battery, MPPT is the default. The price gap has narrowed. The output gap has not. The exception is small trickle setups (say, 30W keeping a starter battery topped up in a shed) where PWM is still fine.
The sizing rule for an MPPT controller is straightforward. Take your panel wattage, divide by your battery voltage, multiply by 1.25 for a safety margin, and that is your minimum amp rating. A 200W panel into a 12V battery requires at least a 20A controller. A 400W array into the same battery wants at least 40A. Going larger than this for future proofing is fine; going smaller will cap your output.
If you are running a caravan or camper that already has a DC-DC charger fitted (and most modern vans do), check whether it has a solar input. Many Redarc, Enerdrive, and Projecta units include MPPT solar regulation built in, in which case you wire the panel into the unit's solar terminals and let the DC-DC manage both the alternator and the solar charge profiles. This is cleaner than running a separate controller and is what most professional installers in Sydney, Melbourne and Brisbane will recommend.
Solar Charge Controller 40A 12V/24V/36V/48V MPPT with Bluetooth
Wiring, Fuses, and the Part That Keeps the Insurance Valid
This is the section most online articles skip and the part that, if you get it wrong, can either burn out your gear or invalidate your van's insurance. Australian caravan electrical work is governed by AS/NZS 3001.2:2022, which sets out requirements for connectable electrical installations on caravans, motorhomes, and similar vehicles. The 240V side of any installation must be done by a licensed electrician. The 12V side is generally permitted as DIY, but the standard still expects sensible practice on cable sizing, fusing, and segregation from the 240V system.
Voltage drop matters more than people think. A 200W panel pushing roughly 11A at 12V over a five-metre run of 6mm² cable will lose about three per cent of its output to cable resistance. Push that to a 10 metre run of 4mm², and you are losing closer to ten per cent. For folding mats, use an Anderson plug lead and resist the temptation to extend it with a thinner cable.
Fuse the positive lead from the panel to the controller, and the positive lead from the controller to the battery. Both fuses should be sized at roughly 1.25 times the maximum current. Without these, a chafed cable inside a sliding drawer can short to the chassis and start a fire that your insurer will be very interested in.
Use Anderson plugs as the standard interconnect, not cigarette lighter plugs. Cigarette plugs are rated for 10A continuous at best, and the contact resistance is awful. Every experienced touring electrician in Australia has horror stories about lighter plugs that have melted around 8A loads.
If you are wiring two folding panels in parallel for more output, use proper MC4 branch connectors with their own fuses, not a Y splitter from a hardware store. The reason is that if one panel develops a fault, you do not want it back feeding from the other panel and overheating the cable.
The Australian Conditions Reality Check
Australia has more solar irradiance than almost any populated country on Earth. It also has the conditions that derate solar output the most aggressively, and these are usually the conditions you will be camping in.
A 200W panel honestly delivering 140W at midday on a Mildura summer day is normal.
Heat is the biggest variable. A panel rated at 200W is tested at 25°C cell temperature. On a 40°C ambient day with the panel sitting in full sun, cell temperature can easily reach 65°C, at which point a typical monocrystalline panel loses around 0.45 per cent of its output per degree above the rated temperature. That is roughly an 18 per cent reduction at the cell, plus another five to ten per cent through cable and controller losses. We have measured this on the bench and in the field with our own VoltX mats as well.
Bushfire smoke is the variable nobody talks about until it hits. During the Black Summer of 2019 to 2020, and again during the 2023 to 2024 fire season, customers reported solar output dropping by 20 to 40 per cent during severe smoke events, with no warning and no obvious haze on the ground. If you are touring in fire-prone areas during summer, plan a 30 per cent buffer into your sizing.
Dust accumulates faster than people expect on outback trips. A panel that has been on the bonnet of a 4WD through Birdsville Track corrugations or up Cape York will be visibly grey within a week and noticeably underperforming. A wipe with a damp microfibre cloth every few days is enough; abrasive scrubbing will damage the anti-reflective coating.
Shade is the silent killer. Most cell array layouts mean that if even one cell of one string is shaded, the whole string drops out. A panel that is 95 per cent in the sun with five per cent shade from a branch can lose 50 per cent or more of its output. The practical solution on a folding mat is to move it. The practical solution on a fixed panel is to choose campsites carefully, or to carry a folding mat as backup.
Cold mornings affect lithium more than they affect panels. LiFePO4 batteries should not be charged below 0°C, and many built-in BMS units will cut off charging at around 2 to 5°C to protect the cells. If you are touring through Alpine Tasmania, the Snowy Mountains, the Flinders Ranges in winter or central New South Wales in July, expect to see slow charging on the first hour or two of sun, and consider a battery with a self-heating BMS for serious cold-weather use.
Three Setups That Actually Work
After more than a thousand customer conversations, three patterns recur often enough that they are worth describing in detail.
The Weekend Caravanner
Hilux and a 19-foot semi off-road van. Two trips a month, mostly weekends, a mix of free camps within four hours of Sydney and the occasional powered site. Couple in their fifties, no kids in the van, fridge runs around 60 amp-hours a day.
Sensible setup: 200W VoltX folding mat, 100Ah LiFePO4 lithium battery as a drop-in replacement for the factory AGM, 20A MPPT charge controller (or factory DC-DC if it has solar input), and 600W pure sine inverter for the kettle and the toaster. Total kit budget in the order of $1,500 to $2,200, depending on inverter choice.
Why this works: the 200W mat refills the day's draw in about six to seven hours of good sun, the lithium gives them three nights of fridge runtime even with no solar input, and the inverter covers the small AC loads they actually use without trying to run an air conditioner.
The Big Lapper
Land Cruiser 200, 22-foot off-road van with rooftop solar already fitted. Retired couple doing the lap clockwise from Brisbane, six to twelve months on the road, larger 110 litre fridge, occasional 240V loads from the inverter for the kettle, microwave and laptop charging.
Sensible setup: existing 200W of rooftop rigid panels supplemented by a 200W VoltX folding mat for shaded camps and overcast days. 200Ah lithium bank (two 100Ah batteries in parallel, or a single 200Ah unit), 40A MPPT controller, 1500W to 2000W pure sine inverter, and DC-DC charger from the tow vehicle. Total kit budget in the $4,500 to $7,000 range, depending on whether they upgrade the existing factory wiring.
Why this works: redundancy. Two solar sources, a battery bank big enough for two cloudy days in a row, and a DC-DC that backs up everything from the alternator on travel days. The folding mat is the insurance policy that lets them park under shade in 40°C western Queensland and still keep the fridge cold.
The 4WD Remote Tourer
Patrol Y62 with a hybrid camper trailer, Simpson Desert and Cape York trips, prefers free camps on station country and remote tracks. Single occupant, 60 litre fridge, no inverter, charges devices from 12V outlets only.
Sensible setup: 160W or 200W folding mat as primary, 100Ah lithium with self-heating BMS, 20A MPPT controller, and hardwired Anderson plug at the front of the trailer for the mat. No inverter at all.
Why this works: weight and complexity matter more on this trip than on the others. Every kilo on the trailer's tongue weight matters for towing dynamics on corrugated roads; every connection matters for reliability when you are 400km from a workshop. Keeping the system simple, with one panel, one battery, and one controller, makes it diagnosable on a track in the rain at five in the afternoon when the fridge has stopped.
The Seven Mistakes We See Most Often
Working in this industry, you watch the same mistakes repeat themselves. The most common, in rough order of frequency:
- Buying the panel before sizing the system. Customers walk in clutching a 100W panel they bought at Bunnings on a whim and want us to make it work. It usually cannot.
- Pairing a lithium battery with a charge controller that does not recognise LiFePO4. The generic AGM profile applied to a lithium battery means chronic undercharging and a battery that never reaches its rated capacity.
- Running a folding mat through a cigarette lighter plug instead of an Anderson plug. The contact resistance kills the output and, eventually, the cable.
- Leaving a panel connected to a battery with no charge controller. People do this with cheap 5W trickle panels, assuming they cannot do harm. They can.
- Connecting two panels in parallel without proper branch connectors and fuses. A fault on one panel back feeds into the other.
- Storing a lithium battery at 100 per cent charge over winter. LiFePO4 prefers to be stored at around 50 to 60 per cent; long periods at 100 per cent slowly damage cell chemistry.
- Assuming a power station is a battery with an inverter and a screen. It still needs to be recharged from a panel, a generator, or a wall socket. The only thing it removes from the standard solar setup is the wiring.
Solar, Generator, or Power Station?
Here are the three options for off-grid power on an Australian caravan, and when each makes sense.
A solar plus battery setup is the right answer for most touring use. It is silent, fuel-free, and once installed, has effectively zero running cost. The downside is the upfront capital and the dependence on the weather.
A petrol inverter generator, like the Gentrax GT2000, is the right answer for short bursts of high load: kettle, microwave, occasional power tool use, and charging a flat battery before a long touring day. It is also the right answer in rare cases where solar simply cannot keep up, such as multiple cloudy days in a row in winter, or running an air conditioner for sustained periods. Many full-timers carry a generator as a backup that they use perhaps three or four times a year, and that is a reasonable use case.
A portable power station is the right answer for occasional use, very short trips, or as a UPS for sensitive electronics. It is not a replacement for a properly installed solar plus lithium system on a serious touring caravan, because the inverter, battery, and charge controller are all built into the same enclosure, and you cannot scale or upgrade them independently.
Most experienced touring customers end up with two of the three: solar plus lithium as the primary system, and either a small generator or a small power station as the backup. Trying to do everything from one tool is usually a compromise.
What to Look for in a Supplier
When choosing a 12V solar supplier in Australia, a few factors come up consistently in conversations with Outbax customers.
Local stock and fast dispatch matter—especially when you’re finalising a setup days before a trip. Outbax warehouses in Sydney and Melbourne offer same-day dispatch for faster processing of orders.
Australian compliance is often overlooked but critical. RCM-marked products that meet AS/NZS standards are easier to insure, simpler to install legally on a caravan, and far less complicated when it comes to warranty claims. The VoltX range meets these requirements.
Warranty coverage should be a baseline consideration, not a bonus. A minimum of 24 months on solar panels is a reasonable benchmark. Many low-cost imports offer only 12 months or effectively none beyond that. Outbax backs its VoltX fixed solar panel range with a 60-month warranty, giving customers added peace of mind.
Reliable support makes a difference when something goes wrong. In practical terms, that means being able to speak to someone when you need help—not relying solely on chat. Outbax customer support operates during Australian business hours from a Sydney-based team.
Returns and consumer protections should be clear and accessible. While ACCC consumer guarantees apply to all Australian retailers, the ease of returning a faulty product can vary. Outbax offers a 60-day change-of-mind policy alongside its statutory warranty obligations—something worth using as a baseline when comparing suppliers.
Conclusion
The simplest test of whether your solar setup works is whether you can park where you actually want to park, for as long as you actually want to stay, without thinking about it. A good system disappears. A bad system becomes the daily anxiety of the trip.
The reason people in this industry talk about getting the sizing right the way they do is that almost nobody gets it right on the first attempt. The factory AGM is too small. The 100W panel is too small. The cigarette plug is wrong. The MPPT controller is missing. The lithium battery was the right answer two years before the customer bought their AGM.
If you are about to spend a thousand dollars or more on a setup, spend half an hour first writing down your real daily energy budget on the back of an envelope. Add up your fridge, your lights, your devices, the inverter loads you will actually run, and pad the total by 30 per cent for cloudy days and bushfire smoke. Then size your panel and battery against that number rather than against a glossy catalogue page. The Hay Plain morning silence is worth getting right.
