Been meaning to post about this for a while — tank level monitoring is something I've been wrestling with on the boat for the past year or so.
I've got Node-RED running alongside Venus OS on a Cerbo GX, and I've managed to pull in a fair amount of data, but fresh water tank levels have always been the awkward one. Currently using a basic capacitive sensor on the hull side, which is... unreliable at best. Reads differently depending on water temperature and whether there's any scale build-up on the GRP.
What I'm really after is a setup where:
- Tank level feeds into Node-RED via MQTT
- Low-level triggers an alert through Telegram (already have this working for battery SOC)
- Data gets logged to InfluxDB/Grafana alongside the Victron stats
Has anyone managed to get ultrasonic sensors working reliably in a vented fresh water tank? I've seen the JSN-SR04T mentioned in various places — seems like it might handle the humidity better than a standard HC-SR04, but I'd want to hear from someone who's actually deployed one long-term rather than just a bench test.
The other option I've been considering is a simple pressure transducer at the tank base. More reliable arguably, but introduces a wetted fitting which I'd rather avoid if possible.
Interested whether anyone on here has tackled this in a marine or narrow boat context specifically — the challenge with boats is that slight heel angles can throw off readings significantly if you're not compensating for it in the flow logic.
What sensors are people actually running, and are you doing any smoothing/averaging in Node-RED to handle the noise?