[BUG / possible regression] ET112 watt value freezes when Cerbo S GX UI enters idle state — Venus OS

Seeing something suspiciously similar on my motorhome setup — ET112 watt reading just freezes the moment the Cerbo S GX touch display goes into its idle/dimmed state, then magically snaps back to reality the second you prod the screen awake again.

Running Venus OS v3.81 with the new GUI v2, and it's 100% reproducible — leave it alone for a few minutes, glance at the remote console on my phone, and the ET112 is still confidently reporting whatever wattage it fancied when the screen nodded off. Meanwhile the actual grid draw has clearly shifted.

Worth noting:

• The underlying VRM data seems fine — values are logging correctly on the portal
• It's purely a display/UI layer issue rather than the meter itself losing the plot
• Rolling back to the old UI appears to sidestep it, but that's hardly a long-term fix

My suspicion is there's some polling or refresh loop that the new GUI parks when the display idles to save power, and the ET112 value just gets orphaned in that process. Victron's devs presumably know about this given how widely the ET112 is used across UK van and cabin setups.

Anyone else on v3.81 with ET112s seeing this? Curious whether it's isolated to the ET112 or if folks with ET340s or other meters on the same RS-485 bus are getting the same frozen breakfast. Drop your firmware version and UI mode below — proper data might help push a fix upstream faster. 🧊

@BaySoul this is a known-ish quirk that's caught a few of us out. The ET112 data acquisition runs fine in the background — what you're likely seeing is a display refresh issue rather than an actual polling freeze. The Cerbo S GX throttles its UI rendering in idle state to save resources, and the ET112 widget can sometimes latch onto the last cached value rather than pulling the live MQTT feed.

Worth checking:

• Venus OS version — anything post 3.10 had some UI scheduling changes
• Whether the actual logged data in VRM shows the freeze or just the local display (if VRM looks fine, it's purely cosmetic)
• Try bumping the display timeout to a longer interval temporarily to confirm the correlation

On my narrowboat setup the fix was simply keeping the display active longer — not ideal but confirmed the root cause before raising a proper ticket with Victron support.

@BaySoul had exactly this on the boat last summer, drove me absolutely mental. Thought the ET112 had died tbh.

Worth checking your Venus OS version — pretty sure there was a dodgy build somewhere around 3.x that made this worse. Also check the DVCC settings while you're poking around, something in there seemed to interact badly with the display timeout on mine.

The reading is still updating in the background (as @ExSquaddie49 says) so at least your actual system isn't affected — just the display lying to you, which is somehow more annoying 😤

Victron's community forum has a proper bug thread on this if you search ET112 + idle.

@BaySoul worth checking whether the freeze is purely cosmetic on the display side or whether it's actually affecting logged data in VRM. In my experience with similar oddities on Venus OS, the portal data has often continued recording correctly even when the local UI looked completely stuck.

One thing I'd try — SSH into the Cerbo and watch the DBUS values for the ET112 directly whilst the screen goes idle. If the values are updating there but not on the touchscreen, you've got your answer pretty quickly. dbus-spy is handy for this.

Also, which Venus OS version are you running? There were a few UI rendering changes around the 3.x releases that introduced some quirky display refresh behaviour. Might be worth cross-referencing on the Victron Community forum as well — Victron staff do occasionally respond to regression reports there.

@BaySoul check your Venus OS version first. There was a period where the GX display driver and the Modbus polling weren't properly decoupled — display going idle could throttle background processes depending on your hardware config.

On my shepherd's hut Cerbo setup I log everything via VRM and the raw data there never freezes even when the touchscreen's been dark for hours. If your VRM logs are showing continuous values then it's purely cosmetic as @CaddyWanderer suggests. If VRM also shows flat lines at the same intervals, that's a different and more serious problem.

Either way, raise it on the Victron community forum with your exact firmware version. They're pretty responsive to ET112 quirks. Don't just assume it's cosmetic and leave it — frozen display data has led people to make bad load decisions before.