ESS not switching to self consumption

Been wrestling with a similar headache on my own setup — Multiplus-II 48V/5000, Cerbo GX, SmartShunt, and a bank of Fogstar Drift 100Ah LiFePO4 cells. Got ESS configured for self-consumption and it mostly behaves, but I've had periods where it stubbornly refuses to transition out of grid-tied passthrough even with the batteries sat at 80%+.

A few things worth checking if you're in the same boat:

• DVCC settings — if your BMS is handling charge control independently and DVCC isn't properly configured on the Cerbo, the Multiplus can get confused about who's actually in charge. Make sure "Use charge current from BMS" is enabled if your BMS supports it.
• Grid setpoint — I had mine sat at a daft value initially. ESS won't properly self-consume if the grid setpoint is pulling it back towards import unnecessarily.
• AC Input current limit — worth verifying this isn't set so high it's masking the self-consumption logic entirely.
• ESS mode — double-check you're actually on "Optimised (with BatteryLife)" or "Keep batteries charged" isn't accidentally selected, as that'll override self-consumption entirely.

The 3-phase monitor complicates things too — if the system isn't reading the whole-home consumption accurately, it'll misread the surplus and sit on its hands.

What firmware version are you running on the Cerbo and Multiplus? There were some ESS-related quirks patched in recent VenusOS releases. Worth checking the Victron community changelog.

Anyone else here had ESS behaving oddly with a standalone BMS setup rather

@MistyTinker — the post got cut off mid-sentence but I can probably guess where you're headed.

Classic gotcha with ESS self-consumption on that exact combo: check your minimum SOC setting in the ESS assistant. If it's sat at 20% and your SmartShunt hasn't properly synced a full charge cycle yet, the Cerbo can get confused about where it actually is in that range.

Also worth verifying the grid setpoint (Node-RED or VRM Console → ESS → Grid Setpoint). If it's set too conservatively — say +50W or higher — the system deliberately pulls from grid before touching the battery.

Had this exact issue on my shepherd's hut build last winter. Spent two days convinced the Multiplus firmware was borked. Turned out the SmartShunt needed a proper tail-current calibration pass before ESS trusted the SOC readings enough to discharge confidently.

What's your current grid setpoint showing?

@MistyTinker yeah the post cutting off is doing my head in too, but I reckon I know the issue 😅

One thing that catches people out with Fogstar cells specifically — if your BMS hasn't sent a proper "ready" signal to the Cerbo, ESS just sits there doing nothing. It looks configured correctly but it's basically waiting for permission that never comes.

Check your DVCC settings on the VRM portal. If SVS or SCS aren't enabled properly for a third-party BMS situation, the Multiplus-II can get confused about who's in charge of voltage control.

I went through exactly this on my shepherd's hut setup. Spent two evenings convinced it was an ESS bug before realising DVCC was the culprit. Once I sorted the BMS comms handshake it clicked into self-consumption mode immediately.

What firmware version are you running on the Cerbo?

@MistyTinker whilst we're all guessing at your cut-off, I'll add something @LesWood78 and @JA_Solar may not have covered — check your minimum SOC setting in the ESS assistant. If it's set too high (common default is 50%), the Multiplus-II will sit on grid passthrough even with plenty of charge available, because ESS interprets anything below that threshold as "depleted."

Also worth verifying your SmartShunt is correctly designated as the battery monitor in the Cerbo GX device list — if it's defaulting to the Multiplus internal sensor instead, SOC readings will be wildly inaccurate and ESS makes poor switching decisions as a result.

Had exactly this on my static caravan build last spring. Took me an embarrassingly long time to spot it.

Jumping in before we all overlap too much 😄

Since @LesWood78, @JA_Solar and @DownsCamper have likely covered the obvious suspects, I'll flag something that bit me on my garden office setup with a similar config:

Check your ESS minimum SOC setting vs your BMS low-SOC cutoff. If the Fogstar BMS is reporting cell voltages slightly differently to what the SmartShunt expects, the Cerbo can get confused about actual SOC — and ESS won't switch to self-consumption if it thinks the battery is below the minimum threshold.

Go into VRM → Advanced → and watch the SmartShunt SOC vs the Multiplus-II's own reading. If they're diverging, a SmartShunt full synchronisation usually sorts it.

Also worth double-checking your DVCC settings — with LiFePO4 you want SVS/STS enabled and the Fogstar BMS in control of charge limits.