Dual Fuel Generator Pros and Cons in Australia
A dual fuel generator is worth it if you already run LPG and your genny sits idle for months between blackouts. For most camping, caravan and work use, petrol, diesel or inverter generators suit better. Here's how to tell.
If that already sounds like you, you're sorted. If you want the numbers on dual fuel generators, plus the Australian LPG rules the US guides skip, read on.
How a Dual Fuel Generator Works
A dual fuel generator runs on petrol or LPG, one at a time. You pick the fuel with a switch, and on some models the engine swaps over as soon as you plug in the gas line.
You'll also see "dual fuel" on big industrial generator sets, and tri fuel units that add natural gas. Neither is what this guide is about. For how every fuel compares, see the guide to generator fuel types.
Switching Between Petrol and LPG
On the petrol side, it's a normal genny with a tank. On the LPG side, the fuel runs from your cylinder, through a regulator and hose, into the engine.
You run one fuel or the other, never both. Posters on a UK motorhome forum say you need to turn the petrol off and run the carby dry before you switch over to LPG.
So which fuel is better? Petrol gives you the full rated output. LPG gives you fuel that keeps. You'll see that trade in every section below.
Dual Fuel Inverter Generators vs Open Frame Models
"Inverter" describes the electrics, so you can buy a dual fuel inverter generator. That build choice decides how loud your genny is, more than the fuel does.
Champion's UK brochures show the gap. Its open frame CHG3500-DF is rated at 72 dBA at 7 metres. Its 73001i-DF inverter is 58 dBA at the same distance.
If there are other campers within earshot, pick the inverter build, whichever fuel you choose.
Dual Fuel Generator Advantages
The big advantage is fuel that keeps. A cleaner-burning engine comes with it.
LPG Storage Without Stale Petrol
The power's been out since last night. You drag the genny out of the shed, where it's sat since last summer, and give the cord a pull.
Nothing. Then nothing again.
The petrol in the tank has gone off and gummed up the carby. You're standing in the rain with a dead genny while your fridge slowly warms up.
With a dual fuel unit, you switch to the LPG side, connect the 9 kg bottle off your barbie, and try again. Fridge humming, and no queue at the servo.
That's the pattern US owners describe in the comments on one dual fuel review. Plenty run theirs on LPG only, and one says their unit eventually wouldn't start on petrol but still ran fine on LPG.
Fair's fair, though. US owners on an RV forum reckon petrol is easier to get and simpler if you only use a generator now and then. If you'd rather stick with petrol, the guide on leaving fuel in your generator covers storing it so your genny still fires up.
Cleaner Running and Less Carburettor Trouble
LPG burns cleaner than petrol. Champion's CHG3500-DF brochure claims LPG means fewer emissions and less wear on your engine.
The practical upside is your carby. Run the genny on LPG only, and no petrol sits in it going stale between blackouts.
So it's more likely to fire up on the night you actually need it.
Dual Fuel Generator Disadvantages
You lose power on LPG, you carry more weight and more parts, you pay more up front, and your LPG often costs more to run than most guides let on.
Less Power Output on LPG
Expect roughly a tenth less power on LPG. EcoFlow's Smart Generator (Dual Fuel) is rated at 1,800W on petrol and 1,600W on LPG, an 11.1% drop. Champion's CHG3500-DF brochure lists 2,700W on petrol and 2,450W on LPG, which is 9.3% less.
US owners on the iRV2 forum see it in real use. One quotes a small dual fuel unit's rating at 1,850 running watts on petrol and 1,665 on propane. Another says the best their 3,400W unit manages on propane is about 1,900W.
So size your genny to the LPG number on the spec sheet. The generator sizing guide walks you through adding up your load, so your fridge and lights stay on when you're on LPG.
LPG Runtime and Running Costs
Plenty of guides say LPG runs longer and costs less. The longer runtime holds up, but only because your LPG bottle holds more fuel than the petrol tank.
Champion's 73001i-DF brochure quotes 8 hours on petrol from a 6-litre tank, against 16 hours on LPG from a 19 kg bottle, both at 25% load. EcoFlow quotes up to 12.5 hours on LPG, measured with a 20 lb tank, which is about 9 kg.
Those extra hours come from hooking up more fuel. They don't mean LPG goes further.
Cost is where owners push back. A licensed LPG fitter on Caravaners Forum, the Australian and New Zealand RV board, pointed out back in 2011 that caravan bottles are expensive to refill, so any real saving needs a fixed Autogas tank on the vehicle. One US owner in the review comments above admits LPG may cost more to run, but reckons the convenience is worth it.
Price a few refills before you buy, and you won't get caught out at the servo.
Weight, Price and Extra Parts
Dual fuel units cost more than a petrol-only genny of the same size, and the bigger ones are heavy. A US owner on iRV2 says their 3,400W dual fuel unit is a struggle to lift into a van or trailer, and you'd be carrying the LPG bottle as well.
The LPG side also adds a hose and a regulator, more parts for you to check and eventually replace. If yours is pull-start, posters on that UK motorhome forum say getting it going on LPG takes more effort than on petrol, and electric start helps a lot.
If you'll be lifting it into a ute on your own, weigh that up before you weigh up the price.
LPG Cylinder Rules in Australia
None of the big guides ranking for dual fuel generators cover Australian LPG cylinder rules, so here's your short version.
Test Dates, Swaps and Autogas Refills
Check the stamp before you pay for a refill. Queensland's gas cylinder safety page says a cylinder's test date is valid for 10 years, and it needs a valid stamp to be refilled.
South Australia's LPG cylinder guidance says the stamp sits on the collar, neck or foot ring, as the letter T followed by the month and year. If it's out of date, get the cylinder tested at an authorised test station or swap it for a newer one.
Never fill a portable cylinder from an Autogas bowser at the servo. South Australia calls that illegal and dangerous.
Carry and store your cylinder upright, in a well ventilated spot outdoors. Queensland also says to fit a valve plug to POL-valve cylinders of 9 kg or less when you take them to swap or refill. And your genny only ever runs outside, which the guide on using generators indoors explains.
Hoses, Regulators and Imported LPG Kits
The rules for portable LPG generators aren't clear-cut, and they vary by state. Energy Safe Victoria says every state and territory has its own laws on selling gas appliances, and that overseas marks like a US CSA or European CE mark aren't enough for appliances that need Australian certification. Its guidance doesn't say whether a generator like yours is one of them.
So check with your state gas regulator before you buy an imported LPG kit or convert a petrol genny. At the very least, South Australia's guidance says your hose and regulator should carry an Australian certification number printed on them, and the hose should be replaced every five years.
Owners have been arguing about this for years. Installers on Caravaners Forum, including that licensed LPG fitter, couldn't agree in 2011 whether free-standing LPG generators with imported parts complied at all. A US owner commenting on a Honda propane conversion video says the conversion voided their warranty. And a UK dealer told one motorhome forum poster it no longer supplies kits for DIY fitting.
Ring your state regulator before the money changes hands.
Not sure which way to go for your setup? Ring the store on 03 7056 6732 and talk it through with a real person.
Dual Fuel vs Petrol, Diesel and Inverter Generators
Dual fuel is worth it for occasional home backup, where your genny can sit for months between blackouts. For most caravan, camping and work use, a single-fuel generator does the job better.
Worth saying plainly: we don't sell a dual fuel generator, so there's no dual fuel sale riding on your decision. Here's where each option fits.
Home Blackout Backup
Yes, this is where dual fuel makes sense. One US owner on iRV2 describes keeping the fridge and essentials going through an outage on LPG only, because a few LPG bottles keep while petrol doesn't.
If you'd rather stay with petrol, a bigger inverter that switches itself on is the simpler setup. The Westinghouse iGen4500AS runs 3,700W from a 13.5-litre tank, lasts up to 17.8 hours at quarter load, and a two-wire link lets a solar controller turn it on and off without you. It's $2,249. The trade is that you'll need to keep its petrol fresh.
Browse generators for home backup and pick the one that keeps your fridge cold through your next outage.
Caravan and Camping Trips
Usually not. You're carrying an LPG bottle as well as the genny, and you lose roughly a tenth of your output on LPG, right when you want every watt for the aircon.
A petrol inverter is the simpler pick. The Hyundai HY3500i gives you 3,000W running and 3,500W starting at 23kg, 60 dB(A) at 7 metres, and 5.5 hours at half load from a 6-litre tank. It's from $1,354.10.
Petrol inverter generators leave you one fuel to carry and one less hose to check at camp.
Work Sites and Long Run Times
No. For heavy, all-day loads, diesel is the better tool, though it's heavier and louder.
The Hyundai DHY6000SE gives you 4,700W rated from a silenced canopy at 74 dB(A), with a 16-litre tank that runs 16 hours at half load. It weighs 152kg, so it lives in one spot. It's from $2,565.20.
The diesel generators range gets you through a full shift and into the next morning before you have to refuel.
Charging a Portable Power Station
Sometimes. A popular setup in the comments on one US review is a small dual fuel genny on LPG, topping up a battery power station instead of running appliances directly.
If that's what you're after, the simpler route is a power station with solar panels, plus a small genny for cloudy stretches. Have a look at portable power stations and you'll hear your generator far less often.
Still weighing it up? Ring the store on 03 7056 6732 or text 0476 330 590, and a real person will match the genny to your job, even when the right answer is a unit we don't sell.
Keep reading: petrol vs diesel generators, generator fuel consumption, best inverter generators in Australia, best generators in Australia and the Generator Finder quiz.
