Most caravanners who end up with the wrong generator did not misunderstand the technology. They got caught by three questions that never got answered properly before they paid: how much power do I actually need, how much weight can I afford to carry, and where am I allowed to run it?
An inverter generator is a petrol generator that passes its raw output through electronic circuitry to produce clean, stable, mains-quality electricity, rather than sending it straight off the alternator. In a caravan, that matters, because you are asking one small machine to charge a laptop and start an air conditioner compressor on the same afternoon.
Here is what they will realistically run, how to size one based on your appliances, how the current range compares, and where you are allowed to use it.
» MORE: Compare inverter generators by rated output and noise level
What an Inverter Generator Does Differently
An inverter generator makes electricity in three stages: the engine produces AC, a rectifier converts it to DC, and an inverter module converts it back to AC at a stable voltage and frequency. Conventional generators skip the last two stages, so their output wanders as engine speed changes.
Three practical consequences follow for caravanners.
Cleaner power. The output is a pure sine wave, the same wave shape you get from a household socket. That is what laptops, camera gear, CPAP machines, and the control boards running your water pump and lighting circuits are built for.
Quieter running. Because the electronics regulate output, the engine doesn’t have to run at a fixed speed. It throttles up and down with demand, so the unit is markedly quieter at light loads. Published noise ratings across the Outbax inverter generator range currently run from 56 dB to 68 dB, measured at seven metres.
Better fuel economy. Most models include an eco mode that drops the engine to the lowest speed that will carry the load. Over a fortnight away, that means fewer jerry cans on the drawbar, which is a weight and fire risk you do not have to carry.
Gentrax GT2-9000I 8kW Portable Inverter Generator
One definition is worth getting right before you shop. Maximum output is the brief peak a unit can deliver. Rated output, sometimes called continuous output, is what it will hold all day. Size against rated output. Every listing in the Outbax range publishes both figures, and so does every reputable manufacturer.
What an Inverter Generator Will Actually Run in Your Caravan
The Everyday Loads
The baseline load in most vans is smaller than people expect. A 12V compressor fridge draws tens of watts while running, and it cycles rather than running flat out. A water pump draws in short bursts when you open a tap. LED lighting is a few watts per fitting. Phone and tablet charging barely registers.
A compact unit covers that comfortably. The Outbax Gentrax GT800 Pro Inverter Generator is rated at 700 W continuous with an 800 W peak, and at 56 dB measured at seven metres, it is the quietest unit in the current range. It includes one 240V outlet, one USB port, and a 12V 4.0A DC socket, and it is recoil start only.
Here’s what one of our customers said about the Gentrax GT800 Pro Generator:
“Ran it a few times and used it to run our cement mixer down the paddock when no electricity ran a couple incubators when we had power issues and charged a battery in caravan good so far happy. Runs quiet will mainly be used in caravans to boost batteries on overcast days.”
Be honest about its limits. At 700 W continuous, it will not run a microwave, a kettle, a heater, or a household fridge whose compressor surges past 800 W on start-up. Outbax says as much in its own hands-on review of the unit, which is worth reading before you commit at that size.
Check the compliance plate on your own appliances rather than trusting generic figures. And if your van already runs on lithium and solar, the generator is usually there to top up the batteries after a run of grey days, not to power the van directly.
Air Conditioning and the Kitchen
Air conditioning is the load that decides your purchase. A 240V rooftop unit runs in the low thousands of watts and demands a short, much higher surge when the compressor kicks in, unless you fit a soft starter. Kettles, air fryers, microwaves, and pod coffee machines sit in a similar band and are normally run one at a time.
That puts you in the 3 kW-rated territory or above. Three units in the current range sit there, and they are not interchangeable.
VoltX VX3850 Pro 2-Wire Inverter Generator
The Gentrax GT3500 Inverter Generator is rated at 3 kW continuous with a 3.5 kW peak, from a 149.5cc air-cooled four-stroke engine. It has dual weatherproof 15A AC outlets plus a 12V 5A DC socket for battery charging, recoil start only, and carries a 12-month warranty.
Here’s what one of our customers said about this unit:,
“Well it generates power as expected, uses a little more fuel than expected, works well so far, due for its first oil change, and arrived quickly.”
The Outbax VoltX VX3850 Pro steps up to 3.5 kW continuous and 3.85 kW peak from a 223cc engine. It takes 91 RON, offers two AC outlets and a DC output, is parallel-capable, starts four ways including remote and ATS, and carries a 36-month warranty, up from the 12 months typical elsewhere in the range.
The Gentrax GTX4200 Pro matches that 3.5 kW continuous rating with a 4.2 kW peak, adding an LCD readout, dual AC outlets with USB ports, parallel capability, and key, remote, and pull start. At 48 kg, it is the heaviest of the three, which matters more than most buyers expect.
Worth knowing: a 12V rooftop air conditioner is a different animal. It draws from your battery bank, not the generator’s 240V sockets, so the generator’s job is to charge the batteries, not run the unit.
How to Work Out What Size You Need
Four steps, and you can do them at the kitchen table before you shop.
List what will run at the same time. Not everything you own. The realistic worst case, which for most people is a hot afternoon with the air conditioner on and the fridge cycling.
Add up the running watts. Take the figures from your compliance plates or manuals, not from an internet average.
Find the single biggest start-up surge. Motors draw far more current for a few seconds at startup. Use the largest single surge in your list, not the sum of them all, because appliances rarely start at the same instant.
Add a margin. Take the running total, add the biggest surge, then add roughly 20% headroom so the unit is not sitting at its ceiling every time it runs.
Here’s an example: say your air conditioner is rated at 1,800 W running with a 2,800 W start-up surge, and your fridge and lights add another 150 W. Your continuous requirement is about 1,950 W and your peak requirement about 2,950 W. With a 20% margin, you are looking for a rated output around 2.3 kW or better and a maximum output comfortably above 3 kW.
How the Range Compares on Paper
The figures below come from current Outbax product listings and were checked on 2 September 2026. Run times are quoted at 50% load and noise ratings at seven metres, which is the measurement distance Outbax publishes. Both vary with load, fuel, altitude, and the unit’s condition, so treat them as a comparison baseline rather than a promise.
| Model | Max / rated output | Weight | Fuel tank | Run time at 50% load | Noise at 7 m |
|---|---|---|---|---|---|
| Gentrax GT800 Pro | 0.8 kW / 0.7 kW | 9.3 kg | 2.1 L | 6.1 hours | 56 dB |
| Gentrax GT2200 Pro | 2.2 kW / 2.0 kW | 22 kg | [Confirm tank capacity] | 4.8 hours | 58 dB |
| Gentrax GT3500 | 3.5 kW / 3.0 kW | 28 kg | 5.7 L | 4.1 hours | 62 dB |
| VoltX VX3850 Pro | 3.85 kW / 3.5 kW | 41.5 kg | 8.8 L | 6.8 hours | 58 dB |
| Gentrax GTX4200 Pro | 4.2 kW / 3.5 kW | 48 kg | 8.8 L | [Confirm: listing and product page differ] | 58 dB |
| Gentrax GTX6600 | 6.6 kW / 6.0 kW | [Confirm] | [Confirm] | 6.6 hours | 62 dB |
Read the rated column, not the maximum column. Then read the weight column beside it, because weight climbs faster than output does. Moving from 3 kW rated to 3.5 kW rated, from the GT3500 to the VoltX VX3850 Pro, buys you 500 W and costs you 13.5 kg. On a van that is already close to its limit, that is the whole decision.
» MORE: Calculate your generator power needs
Gentrax GT1200 Inverter Generator
Where You Can and Cannot Run a Generator in Australia
There is no single national rule, which is exactly why this catches people out.
Caravan parks set their own entry conditions. Many parks prohibit generators outright, on the reasonable basis that they sell powered sites. Others permit them within set hours. The condition sits in the park’s terms, so read them or ring ahead.
National parks and state forests are governed by the relevant state park authority, and policies differ between states and between individual campgrounds within the same state. Some campgrounds ban generators, some allow them only during daylight hours, and some place no restrictions at all. The campground listing on the park authority’s website is the source of truth, and it is updated more often than any third-party guide.
Free camps, showgrounds and station stays vary again, and are often governed by nothing more formal than whoever owns the paddock. Check the campground listing before you book rather than after you arrive, and know your unit’s published noise rating and the distance it was measured at, so that when a rule is written in decibels you can answer honestly. Quiet generator running does not exempt you from a rule. It widens the number of places where the rule works in your favour.
How to Set Up a Generator Safely at Camp
Never run a generator inside, or even partly inside, anything. That includes the caravan, the annexe, a tent, the boot, a storage hatch, or a closed awning. Partly enclosed still counts.
Keep your distance and watch the wind. Outbax and most manufacturers advise positioning the unit several metres clear of windows, doors and vents, with at least five to six metres a common figure. Check your own manual, since clearances vary between models, and consider where the exhaust is drifting relative to your neighbour’s beds as well as your own.
Cool first before refuelling. Switch the engine off and let it cool before you go near the filler. Store petrol in approved containers secured outside the living space, and remember that petrol weighs roughly 0.74 kg per litre when you are counting payload.
Get the 240V connection right. Electrical installations in caravans, camper trailers, and motorhomes are covered by AS/NZS 3001.2:2022, which superseded the older AS/NZS 3001:2008 in November 2023 and requires residual current device protection on AC circuits. Use heavy-duty, outdoor-rated leads in good condition, and have a licensed electrician do any work on the van’s fixed wiring or inlet.
Keep it dry. Most units are not rated for wet operation unless the manufacturer specifically says so.
What to Check on the Spec Sheet Before You Buy
Weight and What It Does to Your Payload
A generator is dead weight you tow everywhere, and the numbers add up faster than they look. The Gentrax GT800 Pro weighs 9.3 kg, plus a full 2.1 L tank, for roughly 11 kg all up. The VoltX VX3850 Pro at 41.5 kg plus 8.8 L of petrol is closer to 48 kg. Petrol weighs roughly 0.74 kg per litre, so a full tank is not a rounding error on the larger units.
Subtract that total from the payload you have left after water, gas, tools, and everything else. Payload is the difference between your van’s aggregate trailer mass and its tare, both shown on the compliance plate. Storing the unit in the front boot also pushes weight forward and increases tow ball mass, which carries its own limit on your tow vehicle. A 48 kg generator sitting ahead of the axle is a meaningful shift, not a detail.
Starter Type, Parallel Capability, and Compliance
Pull start is cheaper and has less to go wrong, and on the smaller units it is all you get. Both the GT800 Pro and the GT3500 are recoil start only. Electric and remote start add a small battery you need to keep charged, and they earn their money if you have limited grip strength, if the unit lives in an awkward hatch, or if you start it most days. The VoltX VX3850 Pro offers four options: recoil, key, remote and ATS, and the Gentrax GTX4200 Pro offers key, remote and pull.
Parallel capability lets two identical units share a load through a matched parallel kit, effectively doubling output. The Gentrax GTX4200 Pro & VoltX VX3850 Pro support it. It suits travellers who normally need little power and occasionally need air conditioning.
Then, check compliance and cover. Gentrax units are Euro 5 emissions certified and RCM approved for sale in Australia, which is the marking to look for on any generator you are considering. Warranty varies more than buyers notice: the GT3500 carries 12 months while the VoltX VX3850 Pro carries 36. For heavy simultaneous loads or full-time touring, the Gentrax GTX6600 Inverter Generator is rated at 6 kW continuous with 6.6 hours at 50% load, though most caravanners never need that much capacity.
Gentrax G3500 Inverter Generator
Buy for Your Numbers, Not for the Biggest Badge
Choosing an inverter generator for caravanning is a balance between power, weight and where you plan to use it. Work out your actual appliance load first, then check the generator’s rated output, starting capacity, weight and noise rating against your setup and the places you travel.
Once you know what you need, explore the Outbax range of inverter generators to find a model that fits your caravan, payload, and travel style.
