Accurately measure propane level for under $10

[Snackchaser]

Although there are several ways to check propane tank levels, I’ve found the easiest way for me is a luggage scale. They have large hooks that balance nicely when hooked on to the fill valve, and they remember the weight so you don’t have to contort yourself to see the scale.  Mine has an analog dial with a memory needle, and thankfully no batteries.  I’d recommend these over ones with batteries that always seem to be dead when you need them.  Flame King sells a more expensive scale made for this purpose.  It conveniently reads in percentage, but it’s battery operated too.

A 30 pound tank weighs around 55 lbs when full, and about 25 lbs when empty.  A 20 pound tank is around 37 lbs full and 17 lbs. empty.  I’ve labeled my tanks with their weights and I can determine exactly how many pounds are left with the scale.  The tanks can be weighed in place with the spin-off clamp loosened, and it helps to put a stick or bar through the scale handle to lift with both hands.

I know some people swear by the Mopeka ultrasonic level detectors, and I heard the newer ones work pretty good.  But I’m still not over the problems and uncertainty of my old ones, so I’ll stick with my trusty scale for now.

Cheers!  Geoff

 

Edited August 6 by Snackchaser
add pic

[John Dorrer]

1 hour ago, Snackchaser said:

Although there are several ways to check propane tank levels, I’ve found the easiest way for me is a luggage scale. They have large hooks that balance nicely when hooked on to the fill valve, and they remember the weight so you don’t have to contort yourself to see the scale.  Mine has an analog dial with a memory needle, and thankfully no batteries.  I’d recommend these over ones with batteries that always seem to be dead when you need them.  Flame King sells a more expensive scale made for this purpose.  It conveniently reads in percentage, but it’s battery operated too.

A 30 pound tank weighs around 55 lbs when full, and about 25 lbs when empty.  A 20 pound tank is around 37 lbs full and 17 lbs. empty.  I’ve labeled my tanks with their weights and I can determine exactly how many pounds are left with the scale.  The tanks can be weighed in place with the spin-off clamp loosened, and it helps to put a stick or bar through the scale handle to lift with both hands.

I know some people swear by the Mopeka ultrasonic level detectors, and I heard the newer ones work pretty good.  But I’m still not over the problems and uncertainty of my old ones, so I’ll stick with my trusty scale for now.

Cheers!  Geoff

 

Great idea. Do you have a link to the luggage scale?

[routlaw]

FWIW, Costco sells 20 lb tanks with a built in gauge. I have only one but it seems to work well enough. Like most things they have had a price increase recently but locally they are running around $42.

[jd1923]

I also had issues with a first batch of Mopeka sensors, however upon complaint the company sent me a new set that has worked well over our last 60 days of travel.

A physical/visual pressure gauge means opening the doghouse to check.

A weight scale means opening the doghouse, removing the LP tank hold-done bracket (ours is padlocked) and then having the strength to lift the tank to measure, make LB to % full calculation, and finally remount tank and doghouse!

I do like the scale approach better than the visual gauge (also often not accurate), but... How often do you want to do this?

When camping, every day we leave the trailer and every night before bed (also when in storage) we check all of our readings by Bluetooth apps. We check the Epoch batteries and all Victron devices to see that batteries are good SOC and amp usage is as expected. Then I check the Ruuvi app for temperatures of 6 sensors (fridge, freezer, truck fridge, basement, cabin, etc.) and we read the Mopeka app for % fill data on both tanks. Want to make sure there is no LP leak (though I would smell it) and I've found when a tank reads 10% or low teens, it's time to switch tanks and then I know we have one to refill.

And my favorite device and app is the LevelMate PRO. I would never want to back into a campsite w/o this great tool and app again! With Chris' help, positioning the Andersen Levelers, we get level without me even getting out of the driver's seat!

These are getting more expensive, but if I had to open the doghouse I just wouldn't bother, then we'd wake up one cold night, furnace cold, to realize one tank has emptied, time to switch (manually) to the other tank. Love app view of important trailer data!

https://www.amazon.com/Mopeka-Pro-Check-Bundle-Wireless/dp/B0BX1CQ6JQ/

Edited August 6 by jd1923

[Corvus]

I've resorted to using a bathroom scale by taring my weight then lifting tanks to check their weight and several other valid methods. I prefer Mopeka for the convenience, but it's nice, and probably safer,  to understand options. Having a way to measure the weight could come in handy in some situations, like boon docking or hurricane dodging. 

[CRM]

Have two 30lb tanks and never even bother to weigh them. Run one tank until it's empty , switch to the full one, and then just plan on filling the empty one as soon as I can. 

[dhaig]

Like @Snackchaser, I use a luggage scale to get an accurate read on the propane level in the tanks.   I purchased a pair of Mopeka sensors and found them to be unreliable and not very accurate.  I had a couple replaced under warranty.  They also seemed to have need frequent battery replacement.  I would NOT recommend them.

Amazon has a large selection of luggage scales for about $10, that are compact and accurate.  With tare weight labelled on both tanks there is no mystery to the amount of propane when the total weight is known.

Such as: https://www.amazon.com/Etekcity-Portable-Handheld-Suitcase-Temperature/dp/B082LYC2TN/ref=sr_1_7?crid=2PAZR2PQNSA24&dib=eyJ2IjoiMSJ9.lrxtiYiAaOxFumPFwJLLfi-V2pD7fJpKxfsl6UyzsKbSFL3YNBR0L1a7Px8SBzHhhW25VLBh912CrUyahxdkUjT1pqB3pRe933JDFfDr7ZaTgoTCb1mXdfINMMhl5OU0FibEUB2mMbq_9R89XeAeSb5MhrkSnnQ5YT6uUSpTQctrjSJqa-90Rcwkt-jGQLzD4jSFjCSRtp-YFlVIJhme_3etEGEES17uG605HrMmwLGyk2YZsL2lLr-nGzZUe7jC60bztrvKDpr9oVktN97bzUFLTJ8jfQEvF9T4OU-tq1A.NFHYzomQyFXtHPcZxq8NaPUGd5FyqkWMxZL0L2YMZgw&dib_tag=se&keywords=digital%2Bluggage%2Bscale&qid=1754537940&sprefix=digital%2Blugga%2Caps%2C138&sr=8-7&th=1 

Don

[Tom and Doreen]

I’ve had problems with the under the tank ultrasonic sensors so I purchased the Truma hand held sensor. It’s expensive but it works well. I’ve also used the (free) method by which you pour hot water down the tank and then feel for the temperature change. The Truma is as accurate as the hot water method (which is very accurate). 

[Ronbrink]

23 hours ago, Tom and Doreen said:

I’ve had problems with the under the tank ultrasonic sensors so I purchased the Truma hand held sensor. It’s expensive but it works well. I’ve also used the (free) method by which you pour hot water down the tank and then feel for the temperature change. The Truma is as accurate as the hot water method (which is very accurate). 

I’ve been using the Dometic equivalent for years and like that levels can be quickly checked while the tanks are still mounted. I also installed GasStop Emergency Propane Shut-Off Valve Gauges on each of three 30# tanks, and find the level indicator very helpful and accurate. 

[HDRider]

On 8/6/2025 at 9:16 PM, CRM said:

Have two 30lb tanks and never even bother to weigh them. Run one tank until it's empty , switch to the full one, and then just plan on filling the empty one as soon as I can. 

I was going to say this same thing.

[Boilermaker Chemist]

I came up with an equally inexpensive yet much simpler approach that also avoids the use of batteries.  I thought about buying the tanks with integrated gauge from Costco that @routlaw mentioned but I didn't like the thought of getting rid of two perfectly good LP tanks.  Then I saw these gauges at my local Wal-Mart for about $15.  They simply screw right onto the tank.  Just open the porthole access and peek inside to see if your tank is empty.  

 

[routlaw]

Good find @Boilermaker Chemist FWIW the main reason I bought a tank from Costco was due to arrive bad tank swap I received on a trip to Utah some time ago. The swap had a bad valve that leaked profusely but did not realize this until back in Montana. So now I am stuck with a full tank of propane I cannot use and no one will take the errant tank in as a trade or otherwise. Suffice it to say I will never do a tank swap again, and would suggest others to avoid as well.

[Boilermaker Chemist]

26 minutes ago, routlaw said:

Suffice it to say I will never do a tank swap again, and would suggest others to avoid as well.

I agree, I always have my own tanks refilled, often at a Tractor Supply.  I find AllStays to be a good app to find sources of propane when I am traveling, not to mention nearest Love's, Costco, etc.  

[Ronbrink]

On 8/21/2025 at 8:10 AM, Ronbrink said:

I also installed GasStop Emergency Propane Shut-Off Valve Gauges on each of three 30# tanks

FYI: Unlike the typical propane tank gas level gauges for backyard cooking/grilling, there is a safety feature in the referenced GasStop (specifically the GasStopRV model) that will shut off flow in the event of a line rupture while the tank valve is open. From their website FAQ:

 

Do propane cylinders already have auto shut-off protection?

In the USA, propane cylinders have inbuilt OPD valves. An OPD valve is an overfill protection device, and as the names suggests will prevent the overfilling of a propane cylinder. GasStop is an Excess Flow Valve (EFV). It is designed to shut down 100% of the flow of propane in the event of a sudden and catastrophic leak. To protect against sudden and catastrophic leaks make sure you install a GasStop. 

Edited Saturday at 12:52 PM by Ronbrink

[aaronorange]

I tried the Gas Stop but our propane generator didn't want to play with them. The Gas Stop see the the flow going to the generator as a leak and shuts off the gas. You probably have an automatic changeover regulator, your setup will automatically switch to the backup propane tank when the first one runs out, provided you leave both tanks open. That being said I usually only open one valve at a time and check my tank level by filling if its getting lighter.  You'll probably get a sense of how much propane your using as you get familiar with your usage. Once I see the gage showing a sliver of red I'll change it. Haven't run out yet but I do watch it closely. I would suggest checking your propane hoses at the tank/regulator connection if you have any kinking or sharp bends. I put 90° elbows on mine when I added (tried) the Gas Stops and that made a major relief on the rubber hoses that from the factory have a pretty sharp bend in them.  

    

[Steph and Dud B]

We just use the auto-changeover regulator. When the first tank runs out it automatically switches to the second tank and the indicator turns red. I check the indicator every day or two. When I see red I plan to replace the empty tank. Haven't run out off propane in 26 years.

[Ronbrink]

9 hours ago, aaronorange said:

I tried the Gas Stop but our propane generator didn't want to play with them. The Gas Stop see the the flow going to the generator as a leak and shuts off the gas

The GasStop has a ‘purge’ feature, which is an important first step when opening a cylinder tank valve. By pressing the pressure gauge several times, the lines are re-pressurized and the internal automatic safety shut-off valve is reset. Just opening the tank valve without purging will not get the propane flowing again. Many have experienced when first opening a tank valve that an appliance will not light and thus, encouraged to go inside the Oliver and turn on the cooktop until there is a flame; basically purging air out of the lines. However, I find this procedure unnecessary since installing these GasStop devices. 

[Boilermaker Chemist]

10 hours ago, Steph and Dud B said:

We just use the auto-changeover regulator. When the first tank runs out it automatically switches to the second tank and the indicator turns red.

I wish I could depend on that.  On my previous rig, the indicator got stuck and no longer worked.  Although it was replaced under warranty, after several months same problem.  Same thing happened on my Oliver.  Seems to be a quality issue.  

[Ronbrink]

21 hours ago, Boilermaker Chemist said:

I wish I could depend on that.  On my previous rig, the indicator got stuck and no longer worked.  Although it was replaced under warranty, after several months same problem.  Same thing happened on my Oliver.  Seems to be a quality issue.  

Using the auto changeover regulator definitely has its pros and cons, but not trusting it is operating as designed or deemed dependable is of dire concern to many. 

On 8/23/2025 at 10:02 PM, Steph and Dud B said:

I check the indicator every day or two.

This is good advice regardless of the mode of operation, and key to ensure one’s propane supply never leaves you empty. However, stuff happens and my contingency is to carry a spare cylinder and regulator. 

[Boilermaker Chemist]

15 minutes ago, Ronbrink said:

Using the auto changeover regulator definitely has its pros and cons, but not trusting it is operating as designed or deemed dependable is of dire concern to many. 

Oh, the changeover regulator works fine, it's just the indicator that stops working. In essence, I just added a couple of new indicators for $30. instead of replacing the whole regulator for $75 and then have the problem happen again.

[Ronbrink]

2 minutes ago, Boilermaker Chemist said:

Oh, the changeover regulator works fine, it's just the indicator that stops working. In essence, I just added a couple of new indicators for $30. instead of replacing the whole regulator for $75 and then have the problem happen again.

Problem solved!