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mauithevan asked

1/2" NPT Temperature Sensor For Monitoring Water Tank With Cerbo

I would like to have my CerboGX monitor the temperature in my fresh water tank.

The user manual says the “required sensor is ASS000001000 - Temperature Sensor QUA/PMP/Venus GX”, which isn't suited for monitoring the temperature of water in a tank. The manual is not clear about what type of input the Cerbo expects from a sensor. I found temperature sensor probes that would screw directly into one of the 1/2” FNPT ports on my fresh water tank which would be an ideal setup, but before I order them it would be nice to confirm they will work.

BTW - I am installing a tank level sensor on the same tank, and the manual was very clear about the need for a “resistive sensor” and the “Ohm ranges” that the Cerbo expects. The same type of information is not included in the temperature section of the manual?


It looks like the Cerbo works well with LM355 based temperature sensors based on this post -> https://community.victronenergy.com/questions/50901/temp-sensors-for-cerbo-gx.html. Is that a specific requirement, or will other types of sensors work?


Based on a search for “water temperature probe 1/2 fpt”, there appear to be RTD (resistive) sensors like the one below. If the Cerbo temperature sensors work like the level sensors, based on resistance, I might expect this option to work… but I wouldn’t know how to hook up the 3 wires to it? The LM355 appears to be a voltage based device, however, so maybe not this one?

RTD PT100 Temperature Sensor Probe 1/2" NPT - 3 wire
https://www.amazon.com/Temperature-58%C2%B0F-572%C2%BAF-Waterproof-Oil-Proof-Anti-Corrosion/dp/B07KFCJJCS


Then there are sensors that use two wires but this one doesnt really seem to say how it works? It seems like type K are voltage based from other research on them...

Waterproof K Type Thermocouple 1/2" inch Pipe Thread - 2 wire
https://www.amazon.com/Waterproof-Type-Thermocouple-Temperature-Controller/dp/B07DP358BK/


Would either of these temperature probes play nicely with the CerboGX? I might be adventurous enough to try the “build your own” solution provided @ https://community.victronenergy.com/questions/166357/cerbo-gx-coolant-temperature-sensor-recomendations.html… but if there is someone who sells 1/2” FNPT sensors that work with the Cerbo, I’d prefer to just buy one.

cerbo gxTemperature Sensortemperature
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1 Answer
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Kevin Windrem answered ·

The sensors you reference are not compatible with the temperature inputs on Cerbo. The Victron sensors have LM355 internally and I have built my own using off the shelf LM355.


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