Anyone else had grief with a Victron MultiPlus cutting out under load? (230V UK setup)

Picked up a second-hand MultiPlus 12/3000/120 a few months back and it's been mostly brilliant, but I keep getting a random shutdown when I'm running my kettle and the induction hob at the same time. We're talking maybe 2,800W combined draw, which should be well within the 3,000VA rating. The unit flashes the overload LED three times and then just dies for a minute before restarting itself. No warning, no gradual fade — just bang, off.

Battery side seems fine — 200Ah of lithium (Winston cells, 12V nominal), resting voltage around 13.2V, and I've got a 300A ANL fuse on the positive with 70mm² cable all the way to the inverter terminals. I've checked the connections twice and everything's torqued up properly. VE.Configure shows the AC output voltage is sitting at a steady 230V before the cut-out, so it doesn't seem to be a low-voltage trip.

Has anyone seen this behaviour before? I'm wondering whether the issue is actually the peak/surge demand from the induction hob rather than the sustained draw — some of those things spike hard when they first kick in. Or could it be a temperature issue inside the unit? It's mounted in a fairly enclosed compartment and it has been warm lately. Would really appreciate any thoughts before I start pulling it apart.

LiamClark72 | 📍 Yorkshire | Posts: 847

@Curly7 Worth checking your DC side before assuming it's the inverter itself. A 12V 3000W unit is pulling a massive 250+ amps from your battery at full chat — any resistance in your cabling, connections or fuse holders will cause a voltage sag that trips the low voltage cutoff.

Grab a multimeter and measure directly across the battery terminals while under load — if you're seeing below 11V or so it'll shut down. Also check your battery cable connections are properly torqued; loose lugs are notorious for this. What battery bank are you running and what cable gauge did the previous owner use? That'll help narrow it down considerably.

DebbieKelly | 📍 Shropshire | Posts: 312

@Curly7 That combination will easily pull 2500W+ so you're pushing that unit pretty hard. One thing worth checking that nobody's mentioned yet — have a look in VictronConnect at your overload warning history. The app logs shutdown events with timestamps and fault codes, which'll tell you pretty quickly whether it's a true overload cutout or something like high temperature shutdown. If it's temperature, improving airflow around the unit often sorts it. Also, what's your battery state of charge when it happens? Low SoC means the MultiPlus has to work harder to maintain voltage. Sometimes it's not the inverter at fault at all.

Nothing screams "I've done exactly this" like watching my Victron throw a strop mid-brew — check your low voltage cutoff settings in VE.Configure, because a 12V system hitting 3000W will drag your battery voltage off a cliff faster than you'd expect, and the MultiPlus will protect itself before you get your cuppa. ☕

Robbo | 📍 Array | Posts: 203

@Curly7 Quick question before you go down the rabbit hole — what's your battery bank sitting at when it cuts out? Because in my shepherd's hut setup I had almost identical grief and it turned out my BMS was throttling discharge before the Victron even had chance to moan about it. The inverter was getting starved, basically.

Also, second-hand unit — do you know if the low voltage disconnect settings have been tweaked by the previous owner? Worth plugging into VictronConnect and having a rummage through the config. Some muppet might have set it conservatively and you'd never know.

Kettle plus induction hob is a bold life choice when you're on a 12V system at that capacity, mind. What's your cable sizing like on the DC side?

JimWilliams71 | 📍 North Yorkshire | Posts: 847

@Curly7 Worth checking your DC cable sizing and connections before anything else. A lot of second-hand units arrive with undersized or corroded cabling from the previous install, and at those loads you'll see a massive voltage drop that triggers the protection. The MultiPlus 12/3000 can pull well over 250A from your batteries at peak — your cables and terminals need to be up to that job. I'd get a multimeter on the battery terminals while under load and see what voltage you're actually reading there versus at the inverter input. If there's more than 0.2V difference you've found your culprit. Also check the connection torque on the battery terminals — loose connections on high-current DC systems are surprisingly common and cause all sorts of phantom shutdowns.

Boycie25 | 📍 Array | Posts: 1,247

@Curly7 Kettle and induction hob simultaneously on a 12V system is absolutely savage — you're asking for somewhere north of 250A DC instantaneous. I'd put money on your battery internal resistance being the culprit rather than anything wrong with the MultiPlus itself. Second-hand unit means you've no idea how the previous owner treated it either.

Get yourself into VictronConnect and pull the VRM history — the low voltage alarm threshold will tell you exactly what's happening at the moment of shutdown. If you're seeing voltage dip below ~11.5V under that combined load, your bank simply can't deliver the current.

Honestly, running a kettle and induction together on 12V is a mug's game regardless. Consider a dedicated 240V immersion or sacrificial kettle on a timer. Worked a treat on my narrowboat setup.