Anyone else had grief with a Victron MultiPlus 24/2000 tripping on high loads in cold weather?

Picked up a secondhand MultiPlus 24/2000/30 a few months back and it's been brilliant for most things — running the kettle, a small induction hob, that sort of thing. But now we're into winter I'm getting nuisance trips when I try to pull anything over about 1,400W. Outside temp last night was around 3°C, and the unit's mounted in an uninsulated outbuilding. Wondering if the cold is throttling the output somehow or if I've got a duff unit.

Battery bank is 4 x 100Ah 24V LiFePO4 (Daly BMS, 100A continuous rating per pack — wired in parallel for 200Ah total). Cables are 70mm², all kept reasonably short, so I don't think it's a voltage drop issue. I've had the VE.Config software on it and nothing looks obviously wrong in the settings, though I'll admit I'm not fully across everything in there.

Has anyone seen thermal derating kick in at low ambient temps on these, or is that more of a high-temp protection thing? I'd have thought cold would actually help keep it cool. Also open to the idea that the BMS is cutting out first and the MultiPlus is just responding to that — hard to tell which is the weak link without better monitoring. Anyone been down this rabbit hole?

VitoAdventure | Member

@TimHarris Classic cold weather behaviour this, and often catches people out. A few things worth checking:

First, what's your battery temperature like? Cold batteries have significantly higher internal resistance, meaning voltage sags harder under load — the MultiPlus will trip on low voltage before it trips on overload. If you're running lead-acid or AGM, even 5°C can make a noticeable difference to available current.

Also worth checking your battery cable cross-section and connection quality. Resistance that's acceptable in summer becomes more problematic when the battery is already struggling.

The MultiPlus itself actually performs better in cold ambient temps, so the inverter isn't usually the culprit here.

What battery chemistry and capacity are you running, and roughly what voltage are you seeing just before it trips? That'd help narrow it down considerably.

@TimHarris yes, classic cold weather behaviour. Battery internal resistance goes up significantly below about 10°C and the MultiPlus will trip on low voltage before the cells can deliver the current — even if your state of charge looks fine.

A few things worth checking:

• Battery temperature — are they inside or exposed to the cold?
• Cable sizing — undersized cables make this worse, voltage drop compounds everything
• VEConfigure settings — the low voltage disconnect threshold might need tweaking slightly for winter conditions

Mine did exactly this on the boat last January. Turned out my 24V LiFePO4 bank (Fogstar cells) was sitting in an uninsulated locker. Insulated the box with some cheap PIR board and the tripping stopped almost entirely.

Also worth checking the DC cable connections for any corrosion if it's been secondhand — poor connections get worse in the cold.

My Fogstar Drift cells in the shepherd's hut do exactly this — trips the MultiPlus faster than I can boil a brew once it drops below 5°C, and the BMS is basically doing you a favour by telling the inverter to take a nap. Worth checking your DC cable runs too; a dodgy crimp that's fine at 20°C becomes a voltage-drop disaster in winter and the MultiPlus will see a sagging bus voltage and assume the worst.

EwanGreen | Member

@TimHarris One thing worth checking that nobody's mentioned yet — have a look at your DC cable run from the batteries to the MultiPlus. Cold weather can cause connections to contract slightly and any marginal crimps or loose terminals will increase resistance noticeably. Even a small voltage drop there gets amplified under high loads like a kettle or induction hob.

Also worth pulling up the VictronConnect app and looking at the actual low voltage trip threshold in the settings — secondhand units sometimes come with non-standard configurations from the previous owner. You might find it's set more conservatively than factory default. The 24V MultiPlus will trip on low DC input before it ever thermally protects itself, so ruling that out first makes sense.

MidlandsExplorer | Member

@TimHarris Worth having a look at your battery temperature sensor as well — if you're running VE.Configure, check whether the low temperature cutoff settings are configured sensibly. Some secondhand units come with settings the previous owner had tweaked for their specific setup, which might not suit yours at all.

Also, what's your battery SOC when these trips happen? If you're going into the colder months already starting pulls from a partially discharged bank, you're stacking two problems on top of each other. Cells that are cold and not fully topped up will sag badly under kettle-sized loads.

@CharlieCampbell66 makes a fair point too — Drift cells are decent but they're not immune to the physics!

LauraCole | Member

@TimHarris Had almost identical issues last winter with mine. One thing I'd add to what's already been said — check your PowerControl and PowerAssist settings in VEConfigure. In cold weather your batteries have higher internal resistance, so they're delivering less power than the MultiPlus expects, and if PowerAssist isn't set up properly it can't compensate quickly enough before the overload protection kicks in.

Also worth checking the "AC input current limit" — sometimes it gets knocked down accidentally and causes confusing behaviour under heavy loads.

Are you running any shore power or generator input at all, or purely off the batteries? That changes things quite a bit. What's your battery capacity and chemistry? LiFePO4 behaves quite differently to lead-acid in the cold and the MultiPlus needs to know what it's dealing with. 🙂