Running out of gas mid-cook is annoying. Running out when you’re relying on gas for hot water and your fridge is worse. The problem with LPG bottles is that there’s no built-in gauge telling you how much gas is left. They feel roughly the same weight whether they’re half-full or nearly empty, and the changeover valve switching to the backup bottle is often the first sign that bottle one is done. A gas bottle monitor removes the guesswork and gives you time to plan a refill before you’re caught out.
How Gas Bottle Monitors Work
There are two main types. Weight-based monitors sit under the gas bottle and measure the weight continuously. Since the bottle itself has a known empty weight (stamped on the bottle), the monitor calculates remaining gas by subtracting empty weight from total weight. These are the most accurate type. Magnetic strip monitors stick to the side of the bottle and use temperature changes to indicate the gas level. They’re cheap ($10 to $20) but less accurate and only show an approximate level.
The best weight-based monitors connect via Bluetooth to your phone, giving you a percentage readout and even estimating days of gas remaining based on your usage pattern.
What We Recommend
Mopeka Pro Check (Best Overall, $80 to $120 per sensor): Ultrasonic sensor that attaches magnetically to the bottom of the bottle. Connects via Bluetooth to your phone or compatible Victron/Simarine systems, so you can see gas levels on your main power monitor. The most accurate consumer option available and increasingly becoming the standard in well-equipped vans.
Gaslock GL3 (Best Dual-Bottle Monitor, $150 to $200): Monitors both gas bottles simultaneously and displays on a panel inside the van. Shows remaining gas as a percentage and alerts you when levels are low. No phone required — the dedicated display is always visible. Popular with travellers who want set-and-forget monitoring.
Truma LevelControl (Premium, $120 to $160): Ultrasonic sensor with Bluetooth app connectivity. Integrates with Truma’s iNet system if you have Truma heating or hot water. Very accurate and well-built, but overkill unless you’re already in the Truma ecosystem.
Companion Gas Level Indicator (Budget, $40 to $60): Simple weight-based pad that sits under one bottle. Basic LCD display shows approximate level. No Bluetooth or smart features, but does the job at a fraction of the price. Good entry-level option if you just want to know roughly where you stand.
Is It Worth It?
Yes. The cost is $40 to $80, the installation takes 5 minutes (place it under the bottle), and the convenience is significant. Knowing you have 3 days of gas left means you can plan to refill at the next town rather than discovering you’re empty at a remote free camp 200km from anywhere. For the price, it’s one of the most practical small upgrades you can make.
A gas bottle monitor ($40 to $80) removes the guesswork from gas management. Weight-based monitors are the most accurate. For the price, it’s one of the most practical small upgrades for any caravan.
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