Hi All,
I am experiencing a strange measurement discrepancy on my ESS system and would appreciate your insights.
System Configuration:
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Grid: 3-Phase with Net-Metering (Import/Export).
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PV Inverter: 3-Phase Fronius Symo Gen24 Plus 10.0 (No battery, On-Grid).
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PV Meters: Fronius TS65A-3 Smart Meter & Victron VM3P75CT (Grid Meter).
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Victron Core: Cerbo GX, Lynx Distributor.
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Inverter/Charger: Quattro 48/10000/140 (Single Phase on L1).
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DC Side: SmartSolar MPPT RS 450/100, SmartSolar MPPT 100/20, SolarMD SS4143 Battery (14.3kWh).
Wiring / Topology: Grid (L1-L2-L3) ↔ Victron VM3P75CT ↔ Fronius Smart Meter ↔ Fronius Inverter & House Loads. Note: The Quattro is connected to the L1 phase only (Off-grid/Essential loads side).
The Integration:
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Fronius is integrated via SunSpec over TCP (Ethernet CAT7).
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Fronius location is set to AC-In 1.
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Phase sequences (L1-L2-L3) are verified and consistent across the Grid, VM3P75CT, and Fronius Smart Meter. I have confirmed this via the VictronConnect app.
The Problem: My legal export limit is 7kW, while my total DC capacity is 17kW. I want Victron to manage the export limiting via ESS to prioritize battery charging and self-consumption while maxing out the 7kW export during mornings and sunsets.
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When I set the 7kW limit on the Fronius Smart Meter, everything works, but the Fronius “throttles” itself based on its own meter, ignoring Victron’s potential for DC charging.
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When I disable the export limit on the Fronius (to give full control to the Victron ESS), the system starts showing wrong values on the L3 phase.
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Specifically, Victron shows a high “AC Load” on L3 (which I know is a ghost load) while Fronius is exporting on that phase. It seems like the Victron Grid Meter is not correctly subtracting the Fronius L3 production from the phase total, or there is a calculation mismatch.
When Fronius exports ~1kW on L3, Victron reports a ~950W AC Load on L3 and almost zero export on that specific phase at the Grid Meter.
Attached Screenshots: I will attach samples below.
Has anyone experienced this “Phase Shift” or calculation error when a 3-phase PV inverter is managed by a single-phase ESS system? Could this be related to the VM3P75CT’s integration or the way ESS calculates “Individual Phase” regulation?
Thanks in advance!
