--- title: "How to Monitor Propane Levels in Your RV" url: "https://camperfaqs.com/how-to-monitor-propane-levels-in-your-rv" author: "Tory Jon" published: "2026-04-06T13:15:01-05:00" modified: "2026-04-16T08:18:35-05:00" --- # How to Monitor Propane Levels in Your RV Sometimes you just want to know how much propane is left in your tanks. Maybe you are getting ready for a trip or deciding if it is worth topping them off before leaving a campground. The reasons vary. The easiest way I have found to check is by using a small sensor that attaches to the bottom of the tank and reports the level to an app on your phone. Let's take a closer look at this method and find out if it's right for you. ## The Method I Use to Monitor Propane Levels The system I use is the **Mopeka propane tank sensor**. It is a small device that magnetically attaches to the bottom of a steel propane cylinder. Instead of measuring pressure, the sensor uses ultrasonic signals to measure the liquid propane level inside the tank. It sends that reading to a smartphone app using Bluetooth. When you open the app, it shows the estimated percentage remaining in each tank. The main advantage is convenience. I can check propane levels from inside the RV or even from the truck before leaving a campsite. That makes it easier to decide when it is time to refill a tank. In my experience, the readings are reasonably close to the actual amount remaining. It is not a laboratory measurement, but it gives a reliable sense of how much propane is left. ## How the Mopeka Sensor Works The Mopeka sensor sits directly against the bottom of the propane tank. A magnetic base holds it in place. Once installed, the device sends a short ultrasonic signal upward through the tank wall. The signal reflects off the surface of the liquid propane. The sensor measures the time it takes for that signal to return and calculates the depth of the propane inside the tank. The reading is then converted into a percentage based on the tank size that you enter in the app. Most RV cylinders are 20-pound or 30-pound tanks. The Mopeka app shows the level for each tank and can send alerts when propane drops below a selected percentage. ## What I Like About This System The biggest benefit is simply knowing how much propane remains. Instead of guessing, I can see a fairly clear estimate at any time. It helps when deciding if a refill is worth doing before leaving home or a campground. If a tank is already getting low, I like to deal with it before hitting the road. Another advantage is that the app tracks multiple tanks. Many RVs use two cylinders with an automatic changeover regulator. With sensors installed on both tanks, it becomes easy to see which tank is being used and how quickly it is dropping. The installation is also simple. The sensor attaches to the bottom of the tank with magnets, and setup through the app only takes a few minutes. For everyday camping, it removes a lot of uncertainty around propane levels. That said, none of this is strictly necessary. The RV will still run fine without it. For me, it just removes some of the guesswork and makes it easier to keep track of propane levels during trips. ## Accuracy and What to Expect The sensor does a good job of showing general propane levels, but it is still an estimate. Temperature changes and tank shape can affect the reading slightly. In my experience, the readings are most useful when the tank is above about one quarter full. Near empty, propane levels can drop quickly, so the last portion of the reading tends to change faster. Even with that limitation, the system provides much better information than a standard pressure gauge. ## The Two Mopeka Models Most RVers See Mopeka currently sells two similar versions of the sensor. The older version is called the **Pro Check**. This model is designed mainly for steel propane cylinders and has been used by RVers for several years. The newer version is the **Pro Check Universal**. It includes updated electronics, longer battery life, and the ability to measure other liquids in addition to propane. For most RV propane tanks, either model works, although many people now choose the Universal version. If your RV uses standard steel propane cylinders, both versions attach magnetically to the tank bottom. ## Common Issues RVers Report With Mopeka Sensors Most RVers find the sensors dependable once they are set up properly, but a few common issues come up in reviews and RV forums. - **Sensor placement** The device needs to sit close to the center of the tank bottom. If it is off to one side, the ultrasonic signal may not reflect correctly from the propane surface. That can cause readings that fluctuate or appear inaccurate. - **Bluetooth range** The sensor connects to your phone using Bluetooth. If the tanks are inside a metal compartment or mounted on the front of a trailer, the signal can sometimes weaken. In those situations, the app may not update until you move closer to the tanks. - **Temperature changes** Propane expands and contracts with temperature shifts. When outside temperatures change quickly, the reported level can move slightly even though the amount of propane in the tank has not changed much. - **Battery replacement** The sensors use coin-cell batteries. These usually last a year or longer, depending on how often the sensor sends readings, but they will need to be replaced periodically. - **Rapid drop near empty** Many users notice the level appears steady for a long time and then drops more quickly as the tank approaches empty. This happens because the remaining liquid propane decreases faster toward the end of the tank. ## Tips for Getting More Accurate Readings A few simple setup steps can improve accuracy significantly. The first step is to **clean the bottom of the propane tank** before installing the sensor. Dirt, rust, or debris can interfere with the ultrasonic signal. Wiping the surface clean helps the sensor sit flat against the tank. The sensor should also be placed **as close to the center of the tank bottom as possible**. This gives the signal a clear path to the propane surface. Mopeka includes a small packet of **coupling gel** with the sensor. Applying this gel between the sensor and the tank improves the transmission of the ultrasonic signal and helps stabilize readings. It also helps to **select the correct tank size in the app**. The software converts the measured liquid depth into a percentage based on tank dimensions. If the wrong tank type is selected, the percentage reading will not match the actual amount remaining. After installation, it is useful to compare the sensor reading with the amount of propane added during your next refill. That quick check helps confirm the sensor is positioned correctly. ## Should You Use a Mopeka Propane Tank Monitor? There are several ways to keep track of propane levels, and plenty of RVers are perfectly comfortable sticking with the basic tank gauges or checking levels manually. If you run dual tanks with an automatic changeover regulator, you may not need a propane monitor at all. The system will switch tanks automatically when one runs out. The main advantage of a monitor is simply knowing how much propane is left, especially if the first tank has already emptied. That information can make it easier to plan refills and avoid surprises during colder weather. For me, the Mopeka sensor has simply been the easiest option to check this. Being able to open the app and see a rough propane level takes the guesswork out of the equation. That said, it is still a consumer device, not a precision instrument. Readings can vary slightly depending on installation, tank condition, and temperature. Like any RV accessory, some owners like them and others decide they are not worth it. If the idea sounds useful, it is worth reading reviews and learning how they work before buying one. There are also other ways to monitor propane levels that may suit your setup just as well. For my RV, the sensor has been a simple and fairly accurate way to keep track of propane without much effort.