Venus OS 3.80 / 3.81: Incorrect AC Loads calculation with gen on AC-in

Been seeing something odd with my Cerbo GX since updating to 3.81 and wondered if anyone else has clocked this.

Running a MultiPlus-II 48/5000 in the shepherd's hut — got a Victron MPPT doing most of the heavy lifting, plus a small AC-coupled inverter on AC-Out. When the genny kicks in on AC-In, the AC Loads figure on the dashboard goes completely mental. Showing numbers that are clearly wrong — either massively over or under depending on what's switched on.

Rolled back to 3.79 thinking that might sort it, but still getting the same weirdness if I'm honest. Makes me wonder if it's something in how Venus OS is calculating the load when there's generation coming in from two directions at once — the AC-coupled side and the genny simultaneously.

The annoying bit is the logging looks off too, so I can't trust my consumption data for the month.

Anyone else running a similar setup — gen on AC-In with AC-coupled PV on AC-Out — noticed anything dodgy after the recent Venus OS updates? Curious whether it's a firmware bug or something in my config that needs tweaking.

Worth flagging on the Victron community forum too if this is widespread. Don't want to be the only one shouting into the void here.

@FormerMachanic15 yes, reproduced this on my Ducato build and cabin setup both. The AC Loads figure on the dashboard goes haywire specifically when the generator kicks in on AC-in — it seems to be double-counting somewhere in the power flow calculation. My loads were showing roughly generator input + actual consumption rather than just actual consumption.

Worth checking: does it correct itself when the gen stops and you're purely on inverter/solar? That's what mine does, which suggests the bug is specifically in how Venus OS handles the AC-in source contribution to the loads display.

I've rolled back to 3.72 on the cabin Cerbo temporarily. The Victron community forum has a thread from a dev acknowledging it — apparently a fix is staged for 3.82. I'd sit tight rather than chasing it manually if you can tolerate the incorrect display for now.

@FormerMechanic15 yeah seeing the same on my garden office setup — MultiPlus-II 48/3000 with a Cerbo. AC Loads reads way off whenever the genny kicks in on AC-in. Went back to 3.70 temporarily and it's fine, so definitely something introduced in the recent releases.

Worth logging it on the Victron Community if you haven't — they're usually pretty responsive and it'll get flagged to the dev team quicker than a forum thread here.

@DucatoSolar good to know it's not just fixed installations affected. Suggests it's the firmware logic rather than a hardware/config thing.

Glad this thread exists — been scratching my head over the same thing on my cabin setup.

@NorfolkCamper and @DucatoSolar — is yours specifically when the generator first kicks in, or does the miscalculation persist throughout the whole gen run? On mine it seems to correct itself after a few minutes but I'm not 100% sure if that's genuine or just the dashboard refreshing weirdly.

Also worth noting: my AC Loads figure was reading lower than expected rather than higher — anyone else seeing that direction of error, or is it going the opposite way for you?

Running a Cerbo GX with a MultiPlus-II 48/3000 as emergency backup. Didn't notice this pre-3.80 at all. Have raised a support ticket but wondering if there's a known workaround whilst Victron sort it.

Victron quietly pushed 3.82 as a fix for exactly this — check the changelog before everyone spends three days reflashing and blaming their CT clamps like last time.