VRM Dashboard incorrect grid export/import on 3-phase MultiPlus-II with Enphase PV

Running into a head-scratcher with my VRM dashboard and wondering if anyone's seen this before.

Setup is three MultiPlus-II 48/5000s in 3-phase, Cerbo GX, and Enphase microinverters integrated via Modbus TCP. No external grid meter — the Multis are doing the metering themselves.

The issue is that the VRM energy dashboard seems to be misreporting grid import and export figures. The solar production numbers look broadly correct, but the grid flow data appears off — sometimes showing import when I'd expect export, and the cumulative daily totals don't add up when I cross-check against what the Enphase Enlighten app is reporting.

A few questions:

• Without a dedicated energy meter (like a Victron ET340 or similar), is the Cerbo actually able to accurately track grid flow across all three phases independently, or does it just sum/average them in a way that causes errors?
• Could the Enphase Modbus TCP integration be causing any confusion — i.e., is the Cerbo double-counting PV somewhere or misidentifying the AC source?
• Would fitting a proper 3-phase meter on the grid connection (before the Multis) fix the dashboard reporting, or is this a firmware/configuration issue?

I've checked the VRM portal settings and the ESS assistant is configured, but I'm not 100% sure the phase compensation settings are correct for UK grid conditions.

Anyone running a similar 3-phase setup with Enphase who's got clean VRM data? Keen to know what you changed to get it accurate.

@CliffWill the Enphase integration via Envoy is notorious for this — the AC coupling on each phase gets misreported when the Cerbo is trying to reconcile Enphase's per-microinverter data with what the MultiPlus-II sees at the AC input.

Few things worth checking:

• Is your ET340 or EM24 energy meter positioned correctly? Wrong CT clamp orientation on any single phase will skew the whole 3-phase balance on VRM
• Check whether you're running the Enphase integration as AC-coupled on AC-out vs AC-in — matters enormously for how VRM interprets the flow direction
• Venus OS version? There were known 3-phase grid meter bugs patched around v3.x

On my boat I only run single-phase so can't test directly, but I've seen this exact thread topic on the Victron Community forum with some detailed responses from Victron devs. Worth cross-posting there honestly.

@CliffWill had almost identical grief on my shepherd's hut build — different scale but same Cerbo/AC-coupled headache.

Worth checking your ESS assistant phase compensation setting. If it's set to "total of all phases" rather than "individual phase" it'll try to balance across all three, which confuses the VRM grid readings something rotten when Enphase is reporting its own AC production numbers separately.

Also double-check the Enphase Envoy polling interval — if it's lagging behind the Cerbo's update cycle you get mismatched snapshots showing phantom import/export spikes.

In VRM, go to Advanced → Device List and check what the individual MultiPlus units are actually reporting per-phase versus what the grid meter shows. If those disagree, your issue is likely a missing or misconfigured grid meter rather than the Enphase integration itself.

What firmware are you running on the Cerbo?

@CliffWill curious whether you've got your Enphase showing up as a PV Inverter on the Cerbo or whether it's landing under AC Loads instead? I had a similar reporting mess on my static caravan setup (single phase, much simpler) and it turned out the device instance numbering was all over the place after a firmware update.

Worth checking in Remote Console → Device List — are all three phases getting their own PV inverter entries, or is it collapsing them somehow?

Also, what firmware version is your Cerbo on? I seem to recall there was a specific Venus OS release that improved 3-phase AC-coupled PV handling. Is the ESS Assistant loaded on all three units identically? Mismatched assistant configs across phases can throw the grid metering figures right out apparently.

Hey @CliffWill, worth checking your CT clamp positioning if you haven't already — on 3-phase AC-coupled setups the Cerbo can get very confused if the grid meter CTs aren't measuring the right reference point relative to where the Enphase is feeding in. If the PV is on the load side of your meter clamps, the dashboard will misattribute export as reduced import (or vice versa) and your numbers will never add up properly. Also double-check your phase assignments in the Venus OS device list — I've seen Enphase systems where phases get swapped during autodiscovery and L1 production ends up reported against L3, which absolutely mangles the grid totals. What firmware are you running on the Cerbo? There were some fixes around AC-coupled reporting in recent Venus OS releases that might be relevant.

@CliffWill one thing nobody's mentioned yet — have you verified the phase assignment in the Modbus-TCP configuration for the Enphase?

On my garden office setup (single-phase, so simpler) I still hit VRM reporting nonsense because the Envoy's phase mapping didn't match what Victron expected. On 3-phase this gets messier fast.

Worth pulling up Device List > PV Inverters on the Cerbo and checking each phase is correctly attributed. If L1/L2/L3 are misassigned, VRM will happily show you phantom exports on one phase while masking real imports on another — looks exactly like what you're describing.

Also — which firmware are you running on the Cerbo? There were some known Enphase Modbus fixes in recent Venus OS releases. I'd check the changelog before spending hours chasing hardware.