Victron Multiplus keeps tripping at night - think it's the freezer but not sure

Had this exact issue last winter with my backup setup. Turned out to be the compressor startup surge on my chest freezer absolutely hammering the inverter for a fraction of a second — even though the running draw was perfectly manageable.

Few things worth checking:

• What's your low voltage cutoff set to? Batteries sag under compressor startup and if your cutoff is a bit aggressive it'll trip before the surge clears. Victron's default settings can be quite conservative.
• Check your AC out 1 vs AC out 2 — if you haven't already, putting the freezer on AC out 2 means the Multiplus can shed it before it causes a full trip
• Dynamic cutoff — if you're running LiFePO4 (Fogstar or similar) make sure your battery profile is set correctly in VictronConnect, lithium sags differently to AGM under surge loads

Also worth pulling up the VRM portal history if you've got a Cerbo or Venus GX connected — the graphs will show you exactly what the voltage and load looked like at the moment of each trip. Takes the guesswork out completely.

What size Multiplus are you running? The 1200VA version struggles more with compressor surge than the 2000VA+. And what batteries?

Has anyone else found the PowerAssist feature actually helping with this scenario, or does it cause more problems than it solves on smaller systems? I've never been fully convinced by it personally but curious what others reckon.

Hey @Spud74, worth checking whether your Multiplus has PowerAssist enabled and what your dynamic current limiter is set to. The startup surge on chest freezers can be brutal — I've seen them pull 6-8x running current for that split second.

One thing that helped me was fitting a soft starter to the freezer compressor. Picked up a Micro-Air EasyStart for about £80 and it made an enormous difference. Completely transformed how my inverter copes with it.

Also check your Victron Connect logs — the Multiplus should show you exactly when it's tripping and why. If it's showing overload rather than low battery, that confirms it's the surge rather than capacity that's the problem.

Compressor surge got me too on the narrowboat last winter — woke up at 2am to that familiar relay-click silence.

What solved it for me was fitting a soft starter on the freezer. Picked up a Micro-Air EasyStart equivalent and the inrush current dropped dramatically. The Multiplus stopped throwing a wobble overnight almost immediately.

Worth also pulling up your VRM history if you've got a Cerbo or Venus device connected — you can actually see the surge spike on the graphs and know exactly what you're dealing with before chasing settings. I spent a week fiddling with transfer limits before I just looked at the data properly.

@WillRoss makes a fair point about PowerAssist, but in my experience the soft starter is the cleaner fix rather than masking the symptom through the inverter settings.

@Spud74 soft-starter relay on the freezer compressor — about £15 on Amazon — saved my Multiplus from its nightly existential crisis in the static van, because apparently 600W of chest freezer thinks it's a welder for the first 200 milliseconds.

@24VPro beat me to the soft-starter but also worth checking your transfer switch settings in VictronConnect — my Multiplus was set to a stupidly low AC input current limit which meant the moment the static caravan freezer cycled on, the whole thing had a meltdown at midnight like me after three pints.

Also: what's your battery setup? If you're running older cells with high internal resistance, the voltage sag during that compressor kick can trigger low-voltage protection before the soft-starter even gets a chance to help — learned that the hard way before I swapped to Fogstar Drift cells last spring.

The soft-starter suggestion is solid, but here's something nobody's mentioned yet — battery internal resistance creeping up on cold nights.

I had this exact drama with the shepherd's hut build last February. Temperatures dropped to -4°C and my Fogstar Drift LiFePO4 cells were throttling output hard under surge load. The BMS was doing its job, cutting power in microseconds, and the Multiplus interpreted that as a fault.

Worth checking your DC voltage logs in VictronConnect during the trip events. If you're seeing the voltage spike downward sharply just before shutdown, it's a battery-side story rather than the inverter itself.

Ran a short extension from the hut to charge the EV one morning and got the same relay-click. Traced it back entirely to cold-soaked batteries struggling to deliver surge current — no freezer involved at all that time.