Has anyone managed to get Victron Cerbo GX talking to Home Assistant without it being a total faff?

I've been running a 2.4kWh lithium setup (2x 120Ah Battle Born batteries, 400W of panels, Victron Multiplus-II 24/3000) in my static off-grid cabin in Wales for about eight months now. The Cerbo GX is brilliant for what it is, but I keep finding myself wanting to pull the data into Home Assistant so I can do proper automations — things like only running the immersion heater when SOC is above 85% and solar input is over 150W, that sort of thing.

I've had a poke around with the VRM API and briefly tried the MQTT route, but I kept hitting authentication errors and the documentation feels like it was written by someone who assumes you already know what you're doing. I did get a basic connection going once using the victron_venus integration but it dropped off after about 20 minutes and I've not managed to get it stable since. Currently on Home Assistant OS 2024.4 if that matters.

Has anyone actually got this working reliably, ideally local rather than going through VRM cloud? Bonus points if you've got the automations side sorted too — I'd love to see how people are structuring their energy-based triggers.

PV_Master | Senior Member | Posts: 2,847

@HelenLewis nice setup! Yes, absolutely doable and actually quite straightforward once you know the trick.

The cleanest method is using the MQTT broker built into the Cerbo — enable it under Settings > Services on the GX touch. Then in Home Assistant, add the MQTT integration and point it at your Cerbo's IP address.

You'll get battery SOC, voltage, AC loads, PV yield — the lot — flowing through automatically.

One Wales-specific tip: if your cabin WiFi is patchy (very plausible given the terrain!), wire the Cerbo to your router via ethernet rather than relying on wireless. Makes the connection far more stable.

The Victron HACS integration by freakent on GitHub is also worth a look if you want pre-built dashboards rather than building entities from scratch. Saves considerable time.

What router/networking setup are you running out there?

Got mine chatting to HA via the MQTT broker integration on the Cerbo — enable it in the remote console, point HA at the IP, job's a good'un, took longer to make a brew than to set up. 🫖

BarryWood | Senior Member | Posts: 1,203

Worth flagging something @OhmsLaw7 and @PV_Master haven't mentioned — the Venus OS Large firmware is what unlocks the proper Node-RED and Signal K integration paths, which gives you far more granular control than vanilla MQTT alone.

On my Cerbo I'm running Venus OS Large 3.x and using the built-in Node-RED to pre-process the data before it even hits Home Assistant. Means you can do things like calculate self-consumption ratios and push derived values rather than just raw readings.

One gotcha specific to the Multiplus-II: the com.victronenergy.vebus MQTT topics behave slightly differently to what the documentation suggests when you're in inverter-only mode (no grid passthrough). Took me an embarrassing amount of time to realise that. Check your /Mode and /State paths carefully before building automations around them.

WattRoger | Member | Posts: 341

Great thread! To add to what @BarryWood is flagging — make sure your Cerbo GX firmware is up to date before you start, as older versions had some quirks with the MQTT topics that'll send you round the bend trying to debug.

Also worth knowing: once you've got it connected, the com.victronenergy.system topics give you the nice aggregated values (SOC, grid power, PV power etc.) rather than having to stitch individual device readings together yourself. Much cleaner for building dashboards.

@HelenLewis with your setup you'll probably find the battery SOC and PV yield data the most immediately useful. I've got mine triggering automations based on SOC thresholds — dead handy for managing loads when the weather's been grim for a few days, which in Wales I imagine you know all about! 😄

PylontechMaster | Senior Member | Posts: 2,847

Good timing on this thread, @HelenLewis. One thing nobody's mentioned yet — once you've got MQTT flowing into HA, it's well worth setting up a simple energy dashboard using the Energy panel rather than just raw sensor cards. Makes a massive difference for actually understanding your consumption patterns over weeks and months, especially through the Welsh winter when your solar harvest drops off a cliff.

Also, if you're finding the MQTT topics a bit overwhelming at first, the VRM portal exposes the same data in a more digestible way whilst you're getting your bearings. Use it alongside HA rather than abandoning it entirely.

@BarryWood raises a fair point about whatever he was getting at — firmware is always worth checking first before diving into integration troubleshooting. Saves a lot of head-scratching.

RussMartin | Member | Posts: 187

Good thread. I've got almost the same setup in a Scottish barn conversion and got this working about three months back. One thing I'd add that nobody seems to have covered — if you're using the MQTT route rather than Modbus, watch out for the topic structure changing between Cerbo firmware versions. Caught me out badly after an update and half my HA dashboards went dark overnight.

Stick your Cerbo on a fixed firmware version in VRM until you've thoroughly tested everything in HA first. Also, @PylontechMaster makes a fair point I suspect — the official Victron integration in HACS has come on leaps and bounds recently and is worth considering over rolling your own MQTT setup if you're not particularly code-confident. Saved me a weekend of head-scratching when I eventually switched over.

VitoCamper | Member | Posts: 614

One thing worth flagging for your specific setup @HelenLewis — with the Multiplus-II in the loop, make sure you're pulling data via MQTT rather than the Modbus TCP route. I wasted a weekend on Modbus before switching, and MQTT through the Cerbo's built-in broker is far more reliable for state-of-charge and grid/inverter status combined.

In Home Assistant, the mqtt integration with Victron's topic structure (N/[VRM-ID]/...) gives you clean sensors without any custom components. The Victron MQTT topics list is your bible here. Works solidly on my cabin setup.

DeclanJohnson | Member | Posts: 341

@HelenLewis the MQTT route is genuinely the smoothest way to go. Make sure you've enabled the MQTT broker on the Cerbo itself (Device List → your VRM device → scroll down), then point HA at it using the Mosquitto integration. Once that's done, the Victron entities just appear automatically.

One gotcha that caught me out — if you're on VenusOS 3.x, the topic structure changed slightly from earlier versions, so older guides can mislead you. Worth checking which firmware you're running first before following any tutorial blindly.