Anyone else had grief with a Victron MultiPlus 12/3000 tripping on high loads in cold weather?

Picked up a second-hand MultiPlus 12/3000/120 a few months back and it's been brilliant for most things — running my kettle, a small induction hob, the usual. But as soon as the temperature dropped below about 5°C last week, it started cutting out under loads I'd never had a problem with before. Talking about a 2kW induction ring that it handles fine in summer. The overload LED flashes briefly and then it resets itself, which is annoying but not the end of the world. Wondering if the unit's just getting cold-soaked overnight in my uninsulated outbuilding.

I've got 200Ah of lithium (a Fogstar Drift 200Ah 12V) and the battery voltage looks solid throughout — sitting around 12.8V under load, so I don't think it's a battery sag issue. I did check the Victron config in VictronConnect and the AC output current limit is set to 16A, which should be plenty. Transfer switch setting is on shore power priority but I'm running it standalone off the solar/battery, no grid connection at all.

Has anyone else seen this in cold conditions? I'm wondering whether the inverter's internal temperature sensor is throttling output or whether there's something else going on. Is it worth pulling the casing off and checking for anything obvious, or should I be talking to the previous owner about warranty history first?

@ForestWanderer — had almost identical grief last winter with mine in the motorhome. Turned out the battery internal resistance was climbing in the cold, causing a voltage sag the MultiPlus interpreted as a fault condition rather than a genuine overload.

Two things that sorted it for me:

• Pre-warming the battery bank — even just running a small load for 20 minutes before hammering the induction hob made a noticeable difference
• Checking the DC cable sizing — my original install had slightly undersized cable runs, and cold weather pushed it over the edge

Worth connecting VictronConnect and watching the DC voltage in real-time under load. If it's dipping below 11V during the trip event, it's almost certainly the battery side rather than the inverter itself. My Fogstar Drift cells were the culprit — lithium isn't immune to cold-weather resistance issues, despite what people assume.

Great thread, glad it's not just me! One thing worth checking that nobody's mentioned yet — have you verified your battery cable cross-section and length? At 12V you're pulling 250A+ under full load, and even a tiny voltage drop across undersized or corroded cables will cause the MultiPlus to see a low battery condition and trip out. Cold weather makes this worse because your Pylontechs (or whatever batteries you're running) will show higher internal resistance anyway.

Pop into VE.Configure and check what your DC input low shut-down voltage is set to — sometimes second-hand units come with settings tweaked by the previous owner. I'd also have a look at the battery temperature sensor if you've got one fitted; @DorsetDweller's point about internal resistance is spot on and the charger profile really does need adjusting for cold conditions.

BorderCruiser | Posts: 847 | Location: Scottish Borders

Worth checking your battery cable cross-section and connection quality before anything else, @ForestWanderer. Cold weather increases resistance throughout the whole system, so marginal connections that were fine in summer can suddenly become the weak link when you're pulling serious current. I've seen 25mm² cable on a 3000W inverter cause exactly this — you really want 70mm² minimum for that unit.

Also worth having a look in VictronConnect at your low voltage cutoff settings. Batteries sag more under load in cold temps, and if your cutoff is set higher than necessary you might be tripping that rather than an overtemperature fault. What does the LED fault pattern show when it trips? That'll point you in the right direction pretty sharpish.

SuffolkOffGrid | Posts: 1,203 | Location: Suffolk/Norfolk border

@ForestWanderer — one thing I'd add that hasn't come up yet: check your VEConfigure settings, specifically the input current limit and the dynamic current limiter. In cold weather your inverter's working harder and drawing more instantaneous current on load spikes (kettle elements and induction hobs are notorious for this).

If dynamic current limiter is enabled it can sometimes cause the unit to be a bit twitchy about how it handles those peaks rather than riding through them cleanly.

Also worth looking at the low battery cutoff voltage threshold — cold batteries sag more under load, so what reads fine at rest might be dipping below your cutoff momentarily. You can tweak that in VEConfigure if needed.

Do you have a Cerbo or Color Control logging? Would help enormously to see what's actually happening at the point of tripping.

JimButler | Posts: 312 | Location: Derbyshire

@ForestWanderer — something worth looking at that nobody's touched on yet: the MultiPlus has a temperature-compensated charge curve, but the inverter side doesn't automatically derate its output threshold for ambient temps. If you're running it in an uninsulated space in winter, the unit itself gets cold and the internal protection can trip earlier than you'd expect.

Try wrapping the installation area with some basic insulation — not the unit itself, obviously, leave it breathing — just the surrounding space. I moved mine into a slightly warmer cupboard last February and the nuisance trips practically vanished overnight.

Also worth checking in VictronConnect whether your low voltage disconnect threshold is set sensibly. Cold batteries sag harder under load, so what looks like sufficient voltage at rest can nosedive the moment your induction hob kicks in.

TelHall | Posts: 64 | Location: Array

Had almost identical grief last winter with my static caravan setup. The MultiPlus has a temperature derating curve — it quietly reduces output capacity as ambient drops, which combined with cold batteries sagging under load is a double whammy.

Worth checking in VictronConnect whether you've got low temperature cutoff settings configured. Also, what's your battery chemistry? My Fogstar Drift LiFePO4 cells have built-in low-temp charge protection which was throttling things from the BMS side simultaneously, making the whole situation worse than it needed to be.

Are you running a BMV or SmartShunt? Watching the actual voltage under load in real-time told me far more than guessing — my cables looked fine visually but the voltage drop at load was brutal until I went up a size.

Brummie86 | Posts: 847 | Location: Array

Yeah had this exact issue in my van last January. Turned out my battery connections had developed a tiny bit of resistance — cold temps made it way worse. Voltage was sagging under load and the MultiPlus was hitting its low voltage cutoff before the trip warning even showed properly.

Grabbed a proper clamp meter and watched the voltage live while kettle was running. Dropped to like 11.2v which explains everything.

Cleaned all the terminals, replaced the crimps on the positive run, problem gone. Worth checking before assuming the unit itself is duff.

AlanPalmer57 | Posts: 43 | Location: Array

Has anyone checked what the MultiPlus is actually reporting via VictronConnect during these trips? Curious whether it's logging an overload fault or a low battery cutoff — because those need very different fixes.

My setup is similar and I've noticed the temperature compensation on the MPPT charging side can leave batteries undercharged in cold spells, meaning they're already a bit low before you even hit a big load. Worth checking your actual resting voltage before you fire up the induction hob?

What battery chemistry are you running @ForestWanderer — LiFePO4 or AGM?

Boycie74 | Posts: 312 | Location: Shropshire

Worth checking your battery cable connections as well — cold weather makes any resistance in a dodgy crimp or loose terminal far more noticeable under heavy load. I had similar symptoms on my 24v setup and it turned out to be nothing fancier than a corroded negative terminal on the battery. The voltage drop under load was enough to trigger the low voltage cutoff.

@AlanPalmer57 makes a good point about VictronConnect — have a look at the alarm history and check what's actually causing the trip before assuming it's the inverter itself. Could save you a lot of head-scratching.

Jim1985 | Posts: 1,204 | Location: Yorkshire

One thing nobody's mentioned yet — check your battery temperature compensation settings in VEConfigure. The MultiPlus will reduce charge current in cold temps which is correct behaviour, but if your absorption/float voltages aren't temperature-compensated properly, the battery voltage can sag badly under load, triggering the low voltage cutoff. Also worth noting that second-hand units sometimes have the transfer switch sensitivity cranked up from a previous install. Had mine tripping on my coffee machine until I adjusted that. What's your battery bank — AGM, lithium, lead acid? Makes a difference to how you'd approach this.

MarineDawn | Posts: 847 | Location: Array

Worth adding to what @Jim1985 touched on — cold LiFePO4 cells have meaningfully higher internal resistance below about 5°C, which means your pack's actual deliverable current drops significantly even if the BMS reports full capacity. Under a 2kW+ induction load, that voltage sag can trigger the MultiPlus's low-voltage cutoff before the BMS does. I saw identical behaviour with my Fogstar Drift 200Ah last winter. The fix was wrapping the battery cabinet in 50mm Celotex offcuts and adding a small reptile heating mat on a thermostat — kept internal temps above 8°C and the tripping stopped completely.