Anyone else had grief with a Victron Multiplus cutting out under load? (240V kettle test)

Right, so I've been pulling my hair out with this for the past week. I've got a Multiplus 12/3000/120-50 running off a 200Ah lithium bank (two 100Ah Battle Born equivalents wired in parallel) and the thing keeps tripping whenever I plug in the kettle. The kettle's a bog-standard Russell Hobbs, rated at 2400W, so in theory the inverter should handle it with headroom to spare.

The shutdown happens almost instantly — not after a few seconds of the kettle running, but right as it fires up. I'm assuming it's the inrush current spiking beyond whatever the Multiplus has set as its overload threshold, but I've not been able to confirm that yet. Cables between the battery and the inverter are 70mm² and about 600mm long, so I don't think it's a voltage drop issue, though I'm open to being wrong.

I've had a dig around in VictronConnect and the only thing I've spotted that might be relevant is the "PowerAssist" setting — currently disabled because I'm not connected to shore power. The event logs just show "Overload L1" each time. Has anyone actually changed the overload trip sensitivity in VE.Configure? I've seen mention of it but can't find a straightforward guide for the Multiplus specifically.

Would love to know if others have hit this with kettles or other resistive loads, and whether tweaking the inverter settings actually sorted it or whether there's a hardware fix I'm missing.

@PikeSeeker what's your cable run length from the battery to the Multiplus? A kettle will pull close to 13A at 12V (roughly 2800W burst) and even slightly undersized or long DC cables will cause a voltage sag that trips the low voltage cutoff.

Had exactly this with my setup before I went 24V — checked the Victron Connect app and could see the voltage dropping to ~11.8V under load. Sorted it by going to 70mm² cable and shortening the run.

Also worth checking your BMS discharge current limit — 200Ah parallel LiFePO4 should handle it fine but if the BMS is set conservatively it'll pull the plug before the Multiplus even complains.

What does VictronConnect show during the cutout?

Hey @PikeSeeker, worth checking your battery BMS settings as well as the cable sizing @LB_Camper mentioned. With two batteries in parallel, if the BMS on either unit is set conservatively on peak discharge current, a kettle's inrush can trip it before the Multiplus even gets a chance to respond properly. I've seen this catch people out more than once. Also, what's your DC system voltage showing on the Victron app just before it cuts out? If it's sagging below 11.5V momentarily, the Multiplus low voltage protection will do exactly what you're describing. Pop the VictronConnect app on and check the alarm history - it'll tell you pretty sharpish whether it's a voltage collapse or an overload event.

Both good points from @LB_Camper and @Robbo51, but I'd add one thing nobody's mentioned yet: check your low voltage disconnect threshold in VictronConnect.

On a 12V Multiplus, the inverter will cut under sustained high-draw loads if the battery voltage sags below the LVD setting — even briefly. A kettle pulling ~2.8kW on a 12V system is asking for roughly 250A+ at the battery terminals, which will absolutely cause transient voltage sag depending on your BMS discharge rating and internal cell resistance.

In my garden office setup I had identical symptoms. Turned out my LVD was set conservatively at 11.8V and the momentary sag under load was tripping it. Bumping it to 11.2V (appropriate for lithium under load) sorted it immediately.

Worth logging a few cycles in VRM or the Victron app to see exactly what voltage you're hitting at the moment of cutout before chasing cable sizing.

Really useful thread — having a similar setup in my garden office (Multiplus 12/2000 on Fogstar Drift 100Ah cells) so following closely.

One thing worth adding: have you checked the AC output wiring from the Multiplus itself? I had intermittent cutouts under kettle load and eventually traced it to a loose terminal on the output side rather than anything on the DC/battery end. Completely overlooked it for weeks because all my attention was on the battery cables.

Worth a quick torque check on every terminal — Victron does publish recommended torque specs in the manual and mine were noticeably under.

Good shout from @HeathOllie on the low voltage disconnect - that's often the culprit. I'd also check whether your Multiplus is configured for Li-ion or AGM in VE.Configure, because the charge/discharge curves are completely different and it can cause unexpected shutdowns if it's still set to AGM defaults from the factory. Had almost identical grief with my own setup last year - turned out the absorption voltage was set wrong and the unit was basically "seeing" a flat battery when it wasn't. Download VE.Configure if you haven't already and have a proper look through the battery settings. Takes about 20 minutes and could save you a lot of head-scratching. What firmware version are you running on it?

Worth checking your DC cable sizing too — people underestimate how much current a 3000W inverter pulls at 12V. You're looking at 250A+ at full load, so even slightly undersized cables will drop voltage enough to trigger the low voltage cutout before your BMS does.

In my shepherd's hut I went with 35mm² tinned copper throughout and proper crimped lugs, made a noticeable difference. Also keep those runs as short as physically possible.

What gauge are you currently running from battery to inverter? That'd help narrow it down quickly.