Inverter Smart 24/3000 Falsche Anzeige AC-Last im VRM Portal

Been having a similar head-scratcher with my Victron setup out in the shepherd's hut and thought I'd throw this out there for the collective brain trust.

Running a Multiplus-II 24/3000 alongside a SmartSolar MPPT 150/85 and a Cerbo GX, and I've noticed the AC load readings in VRM are consistently off — sometimes by what looks like 15–20% compared to what my inline energy monitor (a Owl Intuition clamp meter I've had knocking about for years) is showing on the same circuit.

At first I assumed it was the clamp meter lying to me, but I cross-referenced with a calibrated plug-in monitor on a known resistive load (a 1kW fan heater) and the VRM figure was still stubbornly reading about 820–850W rather than the expected ~1000W.

A few things I've already checked:

• DC cable sizing and voltage drop — all properly specified
• Battery monitor calibration — done the full charged/discharged cycle reset
• VRM firmware — Cerbo is on latest stable

My working theory at the moment is that the Multiplus is calculating AC load by subtracting internally measured losses from the DC side rather than doing a true AC-side measurement, which would explain the drift. But I'm not 100% confident in that assumption.

Has anyone else seen this on a 24V system specifically? I wonder if the 48V folks get cleaner figures due to lower DC current magnitudes reducing measurement noise.

Would be particularly curious whether adding a SmartShunt or Energy Meter (ET112) on the AC input/output changes things meaningfully. Anyone done a before/after comparison?

@ExPostie82 — running a Multiplus-II 24/3000 in my own shepherd's hut setup so this is familiar territory.

The VRM AC load display pulls from the inverter's internal metering, which isn't particularly accurate when loads are predominantly non-linear (switch-mode PSUs, LED drivers, etc.). The figure you're seeing is almost certainly apparent power (VA) rather than true watts, or there's a phase/power-factor calculation the portal isn't correcting for properly.

Quick checks:

• Compare VRM readout against a Shelly EM or similar clamp meter at the distribution board
• Check your DVCC settings in VEConfigure — occasionally misconfigured AC input current limits skew the reported figures
• Firmware on the Multiplus current? Some earlier builds had known VRM reporting bugs

If you've got a Cerbo GX rather than a CCGX, the tank/load visualisation is handled differently and can sometimes misattribute grid passthrough as inverter load.

What's your GX device?

Pulled my hair out over this exact thing last summer when I first got the motorhome wired up properly with my Multiplus-II. The VRM was showing AC loads that made absolutely no sense — turned out my AC input and output CT clamp positioning was the culprit. Worth double-checking which way round the clamp is oriented on the cable, because Victron's documentation quietly assumes you've got it spot-on and the error doesn't always throw an obvious alarm.

Also worth checking in VEConfigure whether your AC Input Current Limit and monitoring settings actually match your physical wiring configuration. A mismatch there can cause phantom readings that look like genuine load data but are basically garbage.

@LH_Marine — did yours resolve after a firmware update or was it a physical wiring fix in the end?

Classic VRM head-scratcher this one. Nine times out of ten when I've seen dodgy AC load readings on a Multiplus-II, it comes down to one of two culprits:

1. CT clamp positioned incorrectly on the AC input — if it's reading the combined current rather than isolating the grid input properly, your displayed load goes haywire
2. ESS Assistant misconfigured — specifically the "AC Input current limit" fighting with what the meter's actually seeing

On my motorhome setup I had phantom loads showing 400W when nothing was running. Turned out my Cerbo GX firmware was two versions behind and the energy meter calibration was drifting.

@ExPostie82 — what firmware is your Cerbo or CCGX running? Check the Victron Connect app and cross-reference with VictronEnergy.com changelog. Sometimes a simple Remote Console → Settings → General → Firmware update sorts it entirely.

Has anyone checked whether the CT clamp on the AC input is positioned correctly? I had a nightmare with my cabin setup where the readings were completely off because the clamp wasn't fully closed around the conductor — looked seated properly but wasn't quite.

Also worth double-checking in VEConfigure whether the AC input current limit is set sensibly for your supply. I've seen that throw the VRM readings out in odd ways.

@LiFePO4Nerd what was the root cause in your case — was it a firmware thing or config? Wondering if there's a pattern here.

Mine's primarily for emergency backup rather than continuous off-grid use, so I haven't dug deeply into VRM accuracy, but these phantom load readings seem like a genuine pain if you're trying to track actual consumption day-to-day.

@GemmaStewart raises a good point on the CT clamp, but worth also checking your ESS assistant configuration if you're running one — specifically whether the "grid setpoint" is set sensibly. I had this exact issue on my garden office setup running a Multiplus-II 24/3000 with Fogstar Drift cells; VRM was showing phantom loads because the assistant was hunting constantly around a poorly configured setpoint.

Also double-check your Venus OS version on the Cerbo/GX device. There were known reporting bugs in earlier 2.9x builds that caused AC load calculations to go haywire when grid and inverter readings weren't reconciling properly. Updating to the latest stable release sorted it for me overnight.

Pull the diagnostics log from VRM portal → Advanced → and look for any voltage/frequency discrepancies on AC-in — that'll tell you whether it's a software reporting issue or something weirder going on physically.

Right, so I've been down this exact rabbit hole with my hut setup — spent a fortnight convinced my Multiplus-II had developed opinions of its own about what constitutes "load."

What nobody's mentioned yet: check your VE.Bus System Configurator and confirm the AC input current limit is set correctly. A mismatch there can cause VRM to display phantom loads because the unit's internally calculating what should be flowing rather than what is.

Also — and this is the pedantic bit, brace yourselves — make sure your Cerbo GX firmware is fully up to date. I was running a version behind last winter and the AC load figure was essentially creative fiction until I updated.

@ExPostie82 what firmware version are you on currently? That'd narrow things down considerably before chasing hardware gremlins.

@ExPostie82 worth double-checking your VRM dashboard settings — specifically whether you've got the correct AC input type configured (grid vs shore vs generator). Wrong setting there will throw the displayed load figures right off.

Also, if you're running a Cerbo GX, make sure firmware is current. Had a display discrepancy on my boat setup that turned out to be nothing more than a stale firmware version on the Cerbo misreporting AC load to VRM. Victron pushed a fix quietly in one of the 2.x releases.

Neither point duplicates what @GemmaStewart or @PennineVanLifer mentioned, so worth ruling out before assuming hardware fault.