Anyone else finding the Victron Cerbo GX temperature sensors a bit hit and miss?

Picked up a pair of the official Victron temperature sensors for my Cerbo GX last month — the ones that plug straight into the dedicated sensor ports. Got them set up to monitor my 200Ah LiFePO4 bank (two 100Ah Fogstar Drift cells in parallel) and the ambient in my van. Cost me about £25 each from a UK supplier which felt steep for what they are.

Problem is, one of them is reading consistently 2–3°C higher than the other even when they're basically side by side on the battery terminals. I've swapped the ports over, updated the Venus OS to the latest build (v3.14), tried reseating the connectors — same result every time. The Cerbo itself seems happy, no error flags, just quietly lying to me about one cell's temperature.

Has anyone else had this, or managed to calibrate them somehow? I know the GX Touch 50 display doesn't give you an offset option natively — wondering if there's a way to fudge it through the console or whether I'm better off just binning one and trying a different sensor altogether. Open to suggestions, even non-Victron alternatives if they'll play nicely with the system.

@Barry1962 had the same issue with mine on the static van — one sensor reading 3°C higher than the other when they were literally taped together for testing. Turned out the cable routing was the culprit; running it too close to the inverter was inducing some weirdness.

Worth checking your sensor firmware is current via VRM — Victron quietly pushed an update a while back that improved accuracy. Also make sure you're using the RJ12 ports not bodging them into anything else (seen people do daft things on here).

If they're still drifting after that, the sensors themselves are cheap enough to swap out. Not exactly precision lab equipment but for battery thermal monitoring they're usually fit for purpose. What kind of variance are you actually seeing?

Hey @Barry1962, worth checking the actual connector seating first before assuming the sensors are faulty — I had a similar head-scratcher with mine and it turned out one wasn't quite fully clicked into the port. Gave it a firm push and the readings came back in line pretty sharpish.

Also, if you're using them on the battery itself, make sure they're properly secured against the cell surface rather than just loosely resting nearby. Ambient air temperature can skew the readings noticeably, especially if there's any airflow around the battery compartment. A bit of self-amalgamating tape to hold them flush against the cells made a decent difference for me.

What firmware version is your Cerbo running? There were a few sensor-related fixes in some of the recent updates that might be worth looking at.

@Barry1962 worth noting that the Victron temperature sensors are NTC thermistors, so resistance-based — even a tiny amount of oxidation or contamination on the RJ12 pins can skew readings noticeably. I'd pull the connectors, give the pins a proper clean with isopropyl alcohol, and reseat firmly.

Also check your Cerbo firmware — there were some known calibration offset issues in earlier releases that caused exactly this kind of drift. VRM portal should show your current version under the device list.

On my own LiFePO4 bank I actually run a secondary Dallas DS18B20 sensor wired directly to the battery terminals as a sanity check against the Victron readings. Costs pennies and gives you a reliable cross-reference point. If both sensors agree after cleaning and firmware update, the issue's almost certainly placement rather than the hardware itself.