Gas keeps your fridge cold on remote free camps, boils the kettle at 5am, and runs the cooktop when you’re 200 kilometres from the nearest powered site. Get the setup wrong and you’re either dealing with a regulator that ices up in the cold, fittings that leak, or bottles you can’t legally refill in half the states you’ll drive through.
This guide covers what you actually need: the right bottle sizes, a regulator that won’t let you down, and the fittings that keep everything sealed. We’ll tell you what to buy and what to skip.
Gas Bottle Sizes: What You Need
Most caravans come with a gas bottle holder on the A-frame designed for two bottles. The three sizes you’ll see are 4kg, 8.5kg (often called 9kg), and 9kg. For a Big Lap, two 9kg bottles are the sweet spot.
Here’s why: a single 9kg bottle running a three-way fridge, cooktop and occasional hot water will last a couple on the road roughly three to five weeks. Two bottles gives you six to ten weeks between refills, which matches how often you’ll pass a servo or gas swap point in remote areas.
| Size | Empty Weight | Full Weight | Best For |
|---|---|---|---|
| 4kg | ~5kg | ~9kg | Small campers, portable cookers |
| 9kg Best Pick | ~9kg | ~18kg | Full-size caravans on a Big Lap |
| 15kg | ~14kg | ~29kg | Large vans, off-grid with gas fridge running full-time |
Two 9kg bottles beats one 15kg bottle for the Big Lap. The 9kg size is the most common swap size in Australia, so you’ll never struggle to exchange one, and running two means you can swap a single empty rather than losing all your gas at once.
Steel vs Composite Bottles
Steel bottles are the standard. They’re cheap (around $80 to $110 for a 9kg empty), tough, and you can swap them at any servo or hardware store. The downside is weight and rust; steel bottles left sitting in salt air will corrode, and they add roughly 9kg empty to your A-frame ball weight.
Composite bottles (like the Viking or Kovarc range) are lighter, won’t rust, and let you see the gas level through the translucent shell. They cost more, around $180 to $250, and here’s the catch: you can’t swap them at most exchange points. You can only refill them, and some servos refuse to refill composite bottles at all.
For most Big Lappers, steel wins on convenience. If you’re weight-critical or towing with a smaller vehicle, composite is worth the premium.
Every gas bottle in Australia must be re-tested and stamped every ten years. Check the test date stamped on the collar before you buy or accept a swapped bottle. An out-of-date bottle cannot legally be refilled, and you’ll be turned away at the servo.
Regulators: The Part That Matters Most
The regulator drops the high pressure from the bottle down to the working pressure your appliances need (2.75 kPa for LPG in Australia). It’s the component most likely to fail, and the one worth spending money on.
You’ve got two choices: a single-stage manual regulator, or a dual cylinder automatic changeover regulator. For a Big Lap, the changeover regulator is the clear winner.
A changeover regulator connects both bottles at once. When one empties, it automatically switches to the second bottle and shows a red indicator so you know it’s time to swap the empty. You never lose gas mid-cook, and you never wake up to a cold fridge because a bottle ran dry overnight.
- Automatic changeover: Switches bottles without you touching anything. Essential for off-grid.
- Indicator window: A red/green window tells you when a bottle is empty before you’re caught out.
- AGA approval: Must carry an Australian Gas Association certification number. No exceptions.
- UV-resistant housing: A-frame regulators cop full sun; cheap plastic housings crack within a year.
- Excess flow protection: Shuts off gas if a hose bursts. Standard on quality units.
Fittings, Hoses & POL Connections
Australian bottles use a POL fitting (the left-hand thread that screws into the bottle valve). Your regulator connects to the bottle via a pigtail hose with a POL fitting on one end. These hoses degrade in UV and should be replaced every few years.
Don’t cheap out on pigtails. A cracked or perished hose is the most common cause of a slow gas leak on a caravan. Braided stainless hoses last longer than rubber and resist abrasion where they rub on the A-frame.
~$45
Never use thread tape (Teflon) on a POL fitting. It’s a metal-to-metal seal designed to work without tape, and thread tape can shred and block your regulator. Hand-tighten firmly, then check for leaks with soapy water.
Our Top Picks
✔ Pros
- Never run out of gas mid-cook
- Clear empty indicator window
- Includes pigtail hoses
✗ Cons
- Housing needs shade to last
- Dearer than a manual regulator
✔ Pros
- Swap anywhere in Australia
- Cheap to buy and replace
- Tough and dependable
✗ Cons
- Heavier than composite
- Can rust in salt air
✔ Pros
- Very light
- Won’t rust
- See gas level at a glance
✗ Cons
- Refill only, can’t be swapped
- Some servos won’t refill them
- More than double the price of steel
Refilling & Swap Rules Around Australia
You’ve got two ways to keep bottles topped up: swap and go, or refill.
Swapping is fastest. You hand over an empty steel bottle at a servo, hardware store or Bunnings and take a full one. Cost is around $25 to $30 for a 9kg swap. The catch is you often get a bottle with less than a full charge, and the swap price is dearer per kilo than refilling.
Refilling means a staff member fills your own bottle on the spot. It’s cheaper (roughly $18 to $22 for a 9kg fill) and you get a genuine full bottle. Not every servo offers it, and it’s less common in remote areas. Composite bottles can only be refilled, never swapped.
In remote Australia, refill whenever you’re below half, not when you’re empty. Gas stops can be 300 or 400 kilometres apart in the outback, and running two bottles low at once is how people end up cooking on a fire.
Safety, Testing & Legal Requirements
Gas is safe when your setup is maintained. The things that catch people out are perished hoses, out-of-date bottles, and dodgy DIY connections.
Every bottle must be re-tested and re-stamped every ten years by a licensed facility. Swap points handle this automatically because they cycle bottles through testing, but if you own composite bottles you’ll need to get them tested yourself.
Check for leaks any time you connect a bottle. Brush soapy water over every fitting with the gas turned on; bubbles mean a leak. Never use a flame to check. And if your caravan has an internal gas appliance, get the whole system gas-certified by a licensed plumber every couple of years, especially before a long trip.
Gas bottles must always be transported and stored upright, outside the living space, in a ventilated compartment. Never carry a spare bottle inside the van. A leaking bottle in an enclosed space is a serious explosion risk.
- Run two 9kg steel bottles: the standard swap size, cheap and available everywhere.
- Fit an automatic changeover regulator so you never lose gas mid-cook or wake to a warm fridge.
- Use braided POL pigtails and replace them every few years before they perish.
- Refill when below half in remote areas; don’t wait until empty.
- Check the ten-year test stamp on every bottle and leak-test fittings with soapy water.
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