Two numbers decide whether a camping generator earns its place in the boot. The first is the wattage it can actually start, not just run. The second is how loud it is at seven metres. Plenty of buyers get one right and the other wrong, then spend the trip resetting an overload light or apologising to the site next door.
Here is how to size a generator against a real appliance list, what a decibel rating means on a powered site or in a national park, and how to run a lead safely back to the van. Figures below come from Gentrax owner manuals and published product specifications. Models differ, so treat your manual as the final word.
What Size Camping Generator Do You Need?
A tent setup running lights, a portable fridge, and device charging usually needs 1kW to 2kW of rated output. A caravan without air conditioning generally needs 2kW to 3kW. Add a rooftop air conditioner, and you are in the 3kW rated class or higher. Those bands are a starting point, not a substitute for your own load list.
Running Watts and Starting Watts Are Different Numbers
Rated output: what the machine supplies continuously. Your total load has to stay under it.
Maximum output: a short peak available while an appliance starts. You cannot run on it.
The gap is narrower than people expect. Gentrax lists the GT3500 model at 3.5kW maximum and 3.0kW rated, and the GT2000 model at 2000W maximum and 1700W rated.
Motors are why the peak matters. Fridges, air conditioners, and pumps draw far more current in the first moments than once they are spinning. Gentrax manuals note that when a motor starts, the red overload indicator and the green output indicator light together for about four seconds. That is normal. If the red light stays on, the load is too high.
Eco mode also works against you at start-up. The manuals are explicit: the economy control switch must be off for devices that need a large starting current, such as a compressor or submersible pump.
Gentrax GS2-7500IE 7kW Portable Inverter Generator
Four Steps to Size It Properly
List only the appliances you will run at the same time. Sizing for everything at once adds weight and costs money.
Take the running watts from each compliance plate or manual. Guessing here is where undersized purchases begin.
Find the single largest starting surge, usually the air conditioner or fridge compressor, and add it to the running total.
Compare that against rated output, not maximum. The manuals warn that exceeding rated load will damage the unit, shorten its life and invalidate the guarantee.
What a 3.5 kW Unit Actually Runs
Outbax publishes appliance guidance for the Gentrax GT3500 Inverter Generator that works as a reality check: a caravan air conditioner up to 2.5hp or roughly 2,000W, a 400L to 600L fridge or freezer, laptop, and phone charging, and power tools up to 2,500W. Those are averages, and your appliance may differ.
Here’s what one of our customers said about this unit:
“Absolutely thrilled - keeps our caravan’s aircon running all night off-grid, I slept like a baby super quiet! and even powers the creature comforts like a barista-style coffee in the morning!”
If your total lands close to the rated figure, buy the next size up. The Outbax GTX4200 Pro Inverter Generator, at 4.2kW maximum and 3.5kW rated, covers that gap.
» MORE: How to calculate your generator power needs
Inverter or Conventional Generator for Camping?
An inverter generator conditions its output electronically before it reaches the socket, producing a pure sine wave close to household power. Laptops, televisions, CPAP machines, and modern fridge electronics are sensitive to the rougher waveform a conventional machine delivers.
A conventional generator is still the rational buy for work lights and basic tools at the lowest cost per watt. For camping, where the load list usually includes something with a circuit board in it, the inverter design earns its premium, and it comes in sizes conventional units do not, such as the Gentrax GT1200 Inverter Generator at 1.2kW maximum and 1.0kW rated.
How Quiet Does a Camping Generator Need to Be?
Quiet enough that nobody asks you to switch it off. That means checking two things: the decibel rating with its measurement distance, and the rules set by whoever manages your site.
Gentrax GT2000 Inverter Generator
A Decibel Rating Without a Distance Means Nothing
Sound falls away sharply with distance, so a rating only counts when the distance is attached. Gentrax units are quoted at seven metres. On Outbax listings, the Gentrax GT2200 Pro Inverter Generator, GTX4200 Pro, and the GT1200 are all rated 58dB at 7m, while the GT3500 and Gentrax GTX3500 sit at 62dB at 7m.
Eco mode helps here too. With the economy control switch on, engine speed tracks the connected load, so a unit idling on a fridge and a few lights is noticeably quieter than the same machine working hard.
Check the Rules Before You Travel
National parks, state forests and caravan parks each set their own conditions. Some ban generators in certain campgrounds, others allow them within set hours, and many caravan parks run quiet periods from early evening. The managing agency is the only reliable source, and a phone call beats a wasted purchase.
» MORE: Quiet generators for camping
Weight, Fuel, and Run Time Trade-Offs
Weight Climbs Faster Than Output
Two generators with the same 3.5kW maximum output can be very different objects. The GS-CEDD 3.5kW model has a net weight of 28kg in its manual, while the GSX-CEDD 3.5kW, which adds electric and remote starting plus a battery, is listed at 37.5kg. The GS-6500IE at 6.6kW maximum weighs 89kg net with an 18.5 litre tank, which is a home backup machine with wheels rather than something you lift into a camper trailer. At the other end, the GSI-BXBE 2000W sits at 18.5kg.
Run Time Figures Need Their Load Stated
Manufacturers quote run time at a specific load, and the load they pick changes the number dramatically. Most Gentrax camping models publish rated continuous operation at 50 per cent load, while the GS-6500IE manual quotes 4 hours 30 minutes at 100 per cent. Those are not comparable, and listings do not always match manuals, so check the manual for the model you are buying.
The manuals also flag a break in period of roughly 25 hours, during which you should stay under 75 per cent of rated capacity, followed by an oil change.
Setting Up Safely at Camp, Including Leads and Placement
Place the generator on firm, level ground, away from buildings or other structures, with the exhaust unobstructed. The manuals state it must never sit against a building or near a canvas or plastic structure such as a tent, and the GS-6500IE manual sets a minimum of 1 metre from buildings or equipment. Exhaust fumes can cause carbon monoxide poisoning, so ventilation isn’t just a comfort issue.
Choosing a Lead for the Run Back to the Van
Match the rating to the load: the AC receptacles and AC protector on the GS-6500IE are rated at 15A, alongside a 30A Australian industrial socket. Leads and adaptors must be rated for the current you draw, not merely fit the plug.
VoltX VX6600 2-Wire Inverter Generator
Account for the distance: voltage drop rises with run length and falls with conductor size, so a long thin lead can look fine and still leave a motor labouring. AS/NZS 3000 and AS/NZS 3001.2 for caravans set the requirements, and a licensed electrician can confirm the right lead.
Keep leads in good order: the manuals require mains extension and supply leads to be in good working condition, and the lead should reach the generator without strain.
Earthing is the step most campers skip. The manuals specify an earth lead of 0.12mm of diameter per ampere, so 10 amps calls for 1.2mm. The wire and stake are not supplied.
Rain, Refuelling, and Running Two Units Together
Never run a generator in rain or snow, and never touch it with wet hands. None of these models is rated for wet weather.
Stop the engine and let it cool before refuelling, then move at least 3 metres from the fuelling spot before restarting.
Do not assume parallel operation is available. The GSI-950 and GS-6500IE manuals both advise against connecting the generator in parallel with any other generator.
Never connect a generator to a commercial power outlet or another electrical source. Wiring one into a house or van circuit requires a licensed electrician.
Kuller 4200 Inverter Generator
Matching the Generator to the Way You Camp
Work through it in the same order. Add up the load and size against rated output, with headroom for the largest starting surge. Check the decibel rating and measurement distance, and confirm the rules for the sites you use. Then sort the placement, the lead and the earthing before the first trip, not in the dark on arrival.
Once you know your number, filtering the Outbax inverter generator range by output and noise level takes a minute, and you will be comparing machines that can do the job.
