MULTIPLUS-II 48/10000 bat 16kwh Cerbo gx et alarm " low battery warning" V.E bus sytem [276]

Been dealing with something similar on the boat recently and thought I'd share in case anyone else has hit this wall.

Running a Victron Multiplus-II 48/5000 paired with a Cerbo GX and a 15kWh Fogstar lithium bank. Everything talks nicely via the VE.Bus cable — Cerbo picks up the battery state, SOC looks sensible on the GX Touch — but I keep getting that nagging low battery alarm [VE.Bus System 276] even when the battery is sitting comfortably above 50%.

What I think is happening is the Multiplus is triggering off its own internal DC input low voltage threshold rather than trusting the BMS data coming through. Classic case of the left hand not knowing what the right hand is doing.

A few things I've tried or am looking at:

• Tweaking the DC input low threshold in VEConfigure — mine was still on defaults which are quite conservative for LiFePO4
• Checking whether ESS Assistant is installed correctly, as apparently that changes how the system handles low battery events
• Making sure the DVCC settings in the Cerbo are actually overriding the Multiplus rather than both fighting for control

Has anyone else had this on a boat or van setup where the BMS is a third-party unit connected via CAN? I'm half wondering if the Cerbo is receiving the BMS data correctly but the Multiplus isn't fully deferring to it.

Would be dead useful to know how others have resolved this — especially if you've got a similar high-capacity 48V setup. Open to any ideas before I resort to emailing Victron support.

@MarineOllie — worth checking your Low Battery Voltage threshold in VEConfigure. The [276] alarm code on VE.Bus typically fires when the Multiplus sees the battery dip below that threshold under load, even momentarily.

On my own Multiplus-II 48/3000 setup (paired with a Cerbo and Fogstar Drift lithium cells), I had identical ghost alarms until I adjusted the DC input low shut-down and restart voltages to properly match my actual BMS cut-off curves.

Key things to verify:

• Dynamic cut-off settings — are these tuned for your chemistry?
• Is your BMS communicating via DVCC through the Cerbo, or running independently?
• Any cable voltage drop between battery terminals and Multiplus DC input?

That last one catches people out regularly — a 0.2V drop under 5kW load is entirely plausible with undersized cabling and looks like a low battery event to the inverter.

@VivaroWanderer makes a good point on the VEConfigure threshold — had exactly this on my boat last winter.

One thing worth checking that nobody's mentioned: are your battery monitor SoC settings actually calibrated to your pack's real capacity? If the Cerbo's calculating SoC based on a mismatched capacity figure, it can trigger low battery alarms well before you're genuinely low.

Also worth looking at:

• Peukert exponent settings for your cell chemistry
• Whether the [276] is firing under heavy load (voltage sag confusing the system)

What battery chemistry are you running — LiFePO4 or lead? Makes a significant difference to where your thresholds should sit. On my setup I had to dial the Low Battery Shutdown back considerably once I switched from AGM to Fogstar lithium cells.

Good shout from @VivaroWanderer and @12V_King on the VEConfigure side, but nobody's mentioned Dynamic Cut-off yet.

On a 48V system with lithium, the cut-off curve matters enormously under load. At high draw, voltage sags hard and the Multiplus can trip the [276] alarm even when your actual state of charge is perfectly fine.

In VEConfigure → Inverter tab, check your Dynamic Cut-off settings match your battery chemistry. LiFePO4 wants different values than the defaults (which are tuned more for lead-acid).

Had this exact headache on my garden office setup — Fogstar 48V cells, kept alarming at 30% SOC under the kettle load. Adjusted the cut-off curve and haven't seen it since.

Also worth confirming your BMS is communicating SOC properly to the Cerbo — if it's flying blind on voltage alone, you're always going to get false triggers.

@GoldenSocket — good point on Dynamic Cut-off, that's actually what caught me out during my van build last year.

I'd also be curious whether @MarineOllie has checked the battery capacity setting in VEConfigure. If it's set too low relative to your actual 15kWh bank, the MultiPlus can trigger [276] alarms prematurely under load because it thinks the battery is more depleted than it actually is.

Also worth looking at your DC cable sizing — significant voltage drop under heavy loads can fool the system into seeing a lower battery voltage than reality. Had this exact issue before I upsized my cabling.

What's your current battery chemistry — lithium or AGM? Changes things quite a bit in terms of which thresholds to prioritise adjusting first.