# Mopeka Tank Sensor for Odd Shape Tanks **URL:** \ **Category:** Modifications\ **Tags:** expert, gx\_device\ **Created:** [2 August 2025 01:51 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682 "2025-08-02T01:51:27Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![offgridcircuits](https://avatars.discourse-cdn.com/v4/letter/o/4491bb/32.png) [@offgridcircuits](https://community.victronenergy.com/u/offgridcircuits)\ **Post date:** [2 August 2025 01:51 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/1 "2025-08-02T01:51:27Z")
Has anyone tackled this with a GUI mod or something else or even Victron? The Mopeka sensor works great. But! only With Rectangular Liquid Tanks (water). My tanks are odd shaped and I think it would be easy to add a calibration to the sensor in the Venus OS to account for this. Perhaps a CM value per 5 gallons and it interpolates the quantity between levels or even just uses the closest value? This would really make this sensor great. ---
**Author:** ![pwfarnell](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/pwfarnell/32/2341_2.png) [@pwfarnell](https://community.victronenergy.com/u/pwfarnell)\ **Post date:** [2 August 2025 09:23 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/2 "2025-08-02T09:23:24Z")
V3.70 of Venus OS will add custom tank shapes for Mopeka sensors. Custom shape is currently available for sensors hard wired to the GX device so you can look on the Cerbo manual for details of this. Alternatively, V3.70 is currently in beta testing if you want to test this function. See the beta thread. > [@Venus OS v3.70~35 available for public testing](https://community.victronenergy.com/t/venus-os-v3-70-24-available-for-public-testing/36338): > > UPDATE Sept 16th: v3.70 beta testing is continued Good day! After having released v3.60 last week, its time to start a new series. If you haven’t seen them yet, make sure to go through the v3.60 slides: [public - Venus OS v3.60 Release - Google Slides](https://ve4.nl/v360-slides) . Change log below, and first please make yourself aware with the beta testing instructions: Instructions 1 of 3: Venus OS beta testing & how to join/install In case you don’t know what this message is about, please start with reading [this link](https://www.victronenergy.com/live/ccgx:beta-testing),… ---
**Author:** ![offgridcircuits](https://avatars.discourse-cdn.com/v4/letter/o/4491bb/32.png) [@offgridcircuits](https://community.victronenergy.com/u/offgridcircuits)\ **Post date:** [2 August 2025 12:53 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/3 "2025-08-02T12:53:54Z")
Thank you for that update. Let’s hope they do it right. I was aware of the hard wire sensors and the input to the 140 tank sensor configuration but unfortunately I cannot use that. ---
**Author:** ![offgridcircuits](https://avatars.discourse-cdn.com/v4/letter/o/4491bb/32.png) [@offgridcircuits](https://community.victronenergy.com/u/offgridcircuits)\ **Post date:** [20 August 2025 14:14 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/4 "2025-08-20T14:14:19Z")
I have the update but there is no documentation of how to set the level increments. I have guessed a few times but the results are inconsistent. When you create a new level point it has a sensor level% and volume %. I assume volume is the tank level and because I have a 100 gallon tank, any percentage such as 30% would be 30 gallons. It doesn’t appear to work this way. Sensor level is a percentage and I believe it should be a cm value. Does anyone have any input on this as no matter what I enter in on a point does not correspond to what you end up with on the level of the tank. I know my tank levels as I “calibrated” it with lines on the translucent tank and I can visually see any water level. The Mopeka measures in CM and in the Victron Console settings you can edit these values. Can anyone figure out how to calculate this? ![Screenshot 2025-08-20 at 7.20.33 AM](https://europe1.discourse-cdn.com/victron/original/3X/c/6/c6ebdd96f6606c20d7bd1ca208c6eeaaec465178.png) ![Screenshot 2025-08-20 at 7.08.13 AM](https://europe1.discourse-cdn.com/victron/original/3X/9/7/97f0810272de8c81ae0d24358c786fdbdfdb9a3d.png) ---
**Author:** ![newfd90](https://avatars.discourse-cdn.com/v4/letter/n/f0a364/32.png) [@newfd90](https://community.victronenergy.com/u/newfd90)\ **Post date:** [16 March 2026 16:59 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/5 "2026-03-16T16:59:48Z")
You ever get an answer to this? I’m trying to do the same with a Gobius BT sensor, but the custom shape data points make no sense as the input dialog only allows values up to 10% ---
**Author:** ![offgridcircuits](https://avatars.discourse-cdn.com/v4/letter/o/4491bb/32.png) [@offgridcircuits](https://community.victronenergy.com/u/offgridcircuits)\ **Post date:** [16 March 2026 17:48 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/6 "2026-03-16T17:48:28Z")
I did not get an answer, but I figured it out. You need to know the level of the tank at what levels you want to enter in. For instance, if you want to enter in ten values, you need to know the level of the liquid at the levels you want to set. Two measurements are provided by having a full and an empty tank. So if you have a know level of X, then solving the capacity of X is to divide the sensor value of X (on the cerbo as the current level) by the full value. Then multiply by 100 to get the current percentage of full. Enter this value into a set value and continue to do this for all the steps you want or need, but you have to have a way of measuring a known value of the tank at any particular level. ---
**Author:** ![newfd90](https://avatars.discourse-cdn.com/v4/letter/n/f0a364/32.png) [@newfd90](https://community.victronenergy.com/u/newfd90)\ **Post date:** [16 March 2026 17:58 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/7 "2026-03-16T17:58:51Z")
Thanks for the reply! That’s what I assumed, and I have the theoretical sensor values (divided by max value for a percentage) for a given full percentage from Gobius’ very nice irregular tank calculator. However, when I try to enter these 10 points into the Cerbo GUI (v2), I can only specify a value from 1% to 10%! Seems like it should range from 0 to 100%, no? ---
**Author:** ![newfd90](https://avatars.discourse-cdn.com/v4/letter/n/f0a364/32.png) [@newfd90](https://community.victronenergy.com/u/newfd90)\ **Post date:** [14 April 2026 13:17 UTC](https://community.victronenergy.com/t/mopeka-tank-sensor-for-odd-shape-tanks/41682/8 "2026-04-14T13:17:30Z")
FYI, this appears to be fixed in 1.72