Cerbo GX cannot see my victron shunt auxilary port (12volt engine battery

Had this exact headache on my narrowboat setup last winter — Cerbo GX could see the aux port voltage fine in the VRM portal online, but getting it to actually display on the local touchscreen brief page was a proper faff.

Turned out I'd saved the widget correctly but hadn't scrolled down to notice there was a second save confirmation buried in the menu — classic Victron UX, bless 'em. 🙄

Few things worth checking if you're in the same boat (literally, in my case):

• Firmware — are you on the latest Venus OS? Some older builds had quirks with the aux input labelling
• Input assignment — in the Cerbo settings, make sure the physical aux port is actually assigned as "Starter Battery" not left as generic voltage monitor
• Brief page widget type — there's a difference between the Battery widget and the DC input widget; easy to grab the wrong one
• VE.Can vs VE.Direct — if your shunt is talking over VE.Direct, double-check the cable's seated properly; I had a dodgy Fogstar install where the connector was almost in

The voltage showing in VRM but not locally usually means the data's definitely there, it's just a display config issue rather than anything terminal.

Anyone else on here running a dual-bank setup on a narrowboat or similar — how did you get the engine start battery displaying cleanly alongside your house bank on the Cerbo? Curious whether anyone's found a neater solution than wrestling with the brief page editor every time Venus OS updates itself.

Hey @EssexNomad, just to fill in the gap on your post (looks like it got cut off!) — are you trying to get the aux voltage showing as a named item on the GX Touch display?

If so, you'll need to go into Settings > System Setup > Battery Monitor and make sure the aux input is configured as "Starter battery" rather than left undefined. Once that's set, it should pull through to the Overview page properly on the local screen.

Also worth double-checking your VE.Direct cable is seated firmly — I had a similar gremlin on my setup where the aux would drop off the local display intermittently but still report fine to VRM. Reseating the cable sorted it completely.

What firmware version are you running on the Cerbo? Some older builds had quirks with aux display behaviour. 🙂

Both posts got cut off which is making this thread a bit of a mystery 😄

From what I can piece together — @EssexNomad, if your Cerbo is seeing the aux voltage in VRM but not on the local touchscreen (GX Touch 50/70), the fix is buried in the display settings rather than the device config itself.

On the touchscreen go to Settings → Display & Language → Show Battery Monitor — make sure the SmartShunt aux input is set as a visible tile. The VRM and local display pull from slightly different display configurations, which catches people out constantly.

Also worth checking your SmartShunt firmware is current via VictronConnect — older firmware had a known quirk where the aux channel wouldn't populate the local tile properly even when the data was technically there.

What firmware version is showing on your shunt currently?

Yeah both posts are truncated which isn't ideal for troubleshooting.

@EssexNomad — just to clarify the terminology here: the SmartShunt has an aux input, not technically an "auxiliary port." Small thing but worth being precise when you're searching Victron's documentation.

That aside, the local display setup is a separate config step from VRM. On the GX Touch you need to go into Settings > System Setup > Battery monitor and make sure it's actually assigned. VRM pulling data doesn't mean the touchscreen is configured to show it — they're independent.

Also worth checking: are you using the starter battery monitoring function on the SmartShunt, or a second dedicated shunt? Makes a difference to how you configure it in the Cerbo. Had a similar faff setting up my garden office system before I realised the aux input needed enabling separately in VictronConnect first.

Both posts being cut off is doing my head in tbh — can't tell if this is a config issue or something weirder.

@EssexNomad from my van setup: the Cerbo doesn't always auto-detect the aux input on the SmartShunt without a bit of poking around. Check Device List → SmartShunt → Setup on the touchscreen and make sure the aux port is actually set to "Starter battery" rather than left as "disabled." Easy to miss.

Also worth checking your VRM device firmware — if the shunt's on an older version it can cause exactly this kind of inconsistency where remote portal sees it but local GX display doesn't.

What firmware are you both running? That'd narrow it down sharpish.