My VW Vanagon Westfalia has a small horizontal propane tank. It’s hard to check the fill level and the Mopeka Tank Check has been a nice option. Unfortunately since I use it only a few times a year and the internal lithium battery can’t be turned off I often have to replace the CR2032 battery before use. Such a waste!
My solution is an external rechargeable battery that is easy to turn off. It holds a higher voltage better and should last much longer, plus, it can easily be turned off and also recharged.
Here is how I added it:
Items Used:
- Mopeka Tank Check Plastic Propane Tank Level Indicator
- AA Battery Holder Bundle
- 3M Scotch-Weld Plastic & Rubber Instant Adhesive PR40
- 3.2V LiFePo4 14430 400mAh Rechargeable Battery
- Optional Dow Corning DC 4 Electrical Insulating Compound
Open up the unit as if you were replacing the battery. Cut and solder the AA battery holder wires. Dremel out a little clearance for the wires and maybe use a dab of silicone grease to seal around them. This grease also works well as an ultrasonic grease for the sensor.
Scuff the battery mounting area and glue. I love this PR40 glue for general use.
By the way, I’m using a AA battery holder since I didn’t find any for the shorter 14430 cell size. Fortunately the spring is long enough to make up the difference, and sliding the cell in the holder can work as an off switch.
A small piece of paper makes a great off switch. Even if left on, this battery may last close to 2 years before needing to be recharged.
Here it is on the tank. I don’t know if it would stay on when driving. It might, but a safety string might be wise if testing that.
Now the battery is nice and full, and that helps the sensor read with high quality.
Cautions:
- My battery location fits for the small horizontal tank, but you probably need to relocate the battery position if you are using it on a different shape tank.
- The extra weight of the battery means it is less likely to stay on the tank when driving. I remove it and keep it in the glove box between checks.
- It’s probably less waterproof.
- It needs the 3.2V LFP battery for the proper voltage. It’s not going to work with an Alkaline AA battery.
I hope you found this helpful. Please leave questions or comments below, including corrections for my tipos.
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Last update by Otmar on9/13/2024
What a helpful pro tip! I’ll give it a go before my next trip.