VM-3P75CT als PV Inverter konfiguriert – keine Leistung im GX/VRM, ESS funktioniert

Bit of a niche one this, but sticking it here because I reckon a few van-to-house crossover folks might have hit the same wall.

I've been expanding my setup beyond the van — running a Victron Quattro II 48/5000 (single phase in my case) with an Ekrano GX, Fogstar Drift LiFePO4 cells on a DIY BMS communicating via CAN, and ESS configured with the whole property load on AC-Out 1. Standard stuff for anyone who's gone down this rabbit hole.

The issue I'm trying to get my head around: I've got an older SMA grid-tie inverter I'm attempting to reuse as a PV source, configured as a PV Inverter role via the GX device list. Thing shows up, communicates, ESS appears to be running — but zero watts showing from the SMA in VRM. The ESS is clearly doing something (battery charge state shifts, grid draw changes) but the portal just shows a blank on PV production.

Questions for anyone who's wrestled with this:

• Is the Modbus/Sunspec polling actually reliable enough to show real-time figures, or does VRM lag significantly behind?
• Anyone confirmed whether DVCC active can cause the GX to effectively ignore or deprioritise third-party PV inverter data in the display layer?
• Does the meter role assignment in the GX need to match your ESS grid setpoint config, or are they independent?

Running firmware 3.40 on the GX. Victron's documentation on this specific combo is... optimistic, shall we say.

Interested whether anyone's got a clean working example of this topology in

@Tommo the thread title hints at a VM-3P75CT configured as a PV inverter — classic GX visibility issue that.

When the Multiplus-II (assuming that's what you're running) has ESS active and a third-party inverter set as "PV Inverter on AC-in/AC-out," the GX device needs the correct Fronius/SolarEdge/generic modbus profile assigned, otherwise you get zero watts showing in VRM despite real power flowing.

Few things worth checking:

• Device list on Cerbo — is it actually appearing under "PV Inverters" or just absent entirely?
• Which AC connection point — in or out?
• Did you assign a Modbus TCP address or are you relying on auto-discovery?

On my narrowboat I had a similar phantom-power situation with a Victron SmartSolar not reporting correctly until I forced a VE.Direct rescan. Sometimes it's embarrassingly simple.

What firmware is the Cerbo on?

@Tommo had something similar-ish when I was dialling in my van setup before scaling up — the GX device can be properly blind to the VM-3P75CT's PV production if the role assignment in the GX menu doesn't match what the device is actually doing.

Worth checking: go into Settings → Modbus TCP → Devices and confirm the unit's registered function matches "PV Inverter" not just a generic meter role. VRM pulls its data from that classification, so ESS can function fine whilst VRM shows nothing — they're pulling from different sources essentially.

Also double-check firmware on both the GX and the CT device are current — Victron pushed a fix a while back specifically around multi-phase PV inverter visibility in VRM.

@Tommo quick question on this — when you say no power showing in GX/VRM, is the VM-3P75CT appearing at all in the device list, or is it completely invisible? Wondering if it's a case of the device role being set correctly in the VE.Config but the GX not polling it properly.

Also, did you assign it a unique VE.Bus address? I ran into address conflicts when I added a second inverter to my tiny house setup and the GX just... ignored one of them silently.

Worth checking Device Configuration in VRM to confirm whether it's registering as a PV inverter rather than defaulting to something else. What GX firmware are you on? Some of the older builds had known quirks with multi-phase CT configurations specifically.

@MultiPlusGeek raises the right question — but also worth checking whether you've got the AC-coupled PV inverter role actually assigned in VEConfigure rather than just assuming it carried over from the van config, because that setting doesn't always migrate gracefully when you bolt new kit onto a Quattro-based ESS. Had a similar head-scratcher on my narrowboat when the Fronius showed up in VRM but reported zero watts — turned out the phase assignment was wrong. Also double-check your grid code setting; a mismatch there can cause the inverter to sit silent like it's sulking. Victron's ESS design guide is your mate here — specifically the AC-coupled section.