Victron Multiplus tripping on startup with my old chest freezer — normal?

Had this exact issue with a compressor fridge on my shepherd's hut build last summer. The startup surge was absolutely hammering my Multiplus 12/3000 — kept triggering the overload protection even though the freezer's running wattage is only around 150W.

A few things worth considering:

Is it the PowerAssist or transfer switch relay clicking, or a full shutdown? There's a difference between a momentary hiccup and the unit actually tripping to fault.

Compressor startup surges can be brutal. Older chest freezers are particularly bad — the capacitors and motor windings degrade over time, so the inrush current gets worse as the unit ages. Some older units can pull 6-8x their running current for that half-second kick.

What I did that helped:

• Enabled the ESS assistant and tweaked the dynamic current limiter settings in VictronConnect
• Added a soft starter — there are cheap 16A ones on Amazon that genuinely work
• Made sure my battery cables were properly sized (voltage sag on startup was making it worse)

Worth checking what your battery setup is too. If you're on a smaller LiFePO4 pack with a BMS that has aggressive current limits, the BMS might actually be the culprit cutting out rather than the Multiplus itself.

What size Multiplus are you running and what's your battery bank? That'd help narrow it down. Others on here with van conversions and static caravans have had similar — it's a surprisingly common thread.

@RussScott classic compressor surge headache — been there on the narrowboat with an ancient chest freezer I foolishly thought would "do the job."

The bit nobody tells you upfront is that older compressors are far worse offenders than modern inverter-type fridges. The startup inrush on a tatty 1990s chest freezer can hit 5–6x running current for a split second.

Few things worth trying before you give up:

• Soft starter — NVCal or similar, shoved inline, transformed my situation overnight
• Check your DC cable sizing — voltage sag at the battery end makes the Multiplus work even harder
• Fogstar cells with decent BMS helped me massively; the Multiplus was browning out partly because my old leisure batteries couldn't deliver clean current fast enough

What's your battery setup? That's often the silent culprit everyone ignores.

@RussScott had the same problem with my shepherd's hut setup — old chest freezer was an absolute nightmare on startup.

A couple of things that helped me:

• PowerAssist — make sure it's configured properly in VictronConnect, it can help buffer those surge peaks
• Soft starter — worth fitting one inline if the freezer hasn't got one built in. Massive difference on my system
• The Multiplus 12/3000 has a peak power rating considerably higher than continuous, but older compressors can still exceed it on a cold start

Also worth checking your battery internal resistance — if your cells are tired, voltage sag during startup makes the inverter's job even harder. Fogstar Drift LiFePO4 transformed my system when I upgraded from old AGMs.

What battery chemistry are you running? That's often the hidden culprit rather than the inverter itself.

@RussScott one thing worth trying before you bin the freezer or upgrade the inverter — have a look at a soft starter. Devices like the Micro-Air EasyStart are designed exactly for this, they ramp the compressor up gradually rather than that brutal surge hitting all at once. Made a massive difference on my setup.

Also worth checking what your battery bank looks like. Old or undersized batteries with high internal resistance will sag badly under surge loads even if the Multiplus itself could theoretically handle it — the inverter sees that voltage drop and panics. What are you running for batteries? And how old is the freezer roughly? Some of the older motors are genuinely just far too surge-heavy to be practical off-grid, in which case a modern A+++ rated chest freezer might actually pay for itself pretty quickly.

@RussScott this is almost exactly what I went through with my shepherd's hut. Old chest freezer I'd rescued from a barn — brilliant insulation, but the startup current was absolutely savage.

What nobody mentioned to me at the time was that the transfer switch setting in the Multiplus can make a real difference. I dropped the dynamic current limiter threshold down through VictronConnect and it gave the inverter a fighting chance to prepare itself rather than getting blindsided.

Also worth checking your battery cable runs — I had a dodgy connection on my Fogstar lithium bank that was adding just enough resistance to push the voltage drop over the edge during that surge. Fixed the connection and suddenly the same freezer that had been tripping everything was behaving perfectly. Sometimes it's not the inverter at all.