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

Had this exact issue last year with my static caravan setup. Old chest freezer was tripping my Multiplus-II 24/3000 every single time the compressor tried to kick in — absolutely maddening.

The problem is the startup surge on older compressors. They can pull 4-6x their running current in that first half second, and if your Multiplus isn't sized generously enough (or your battery cables have too much resistance), it sees that spike and protects itself.

A few things that helped in my situation:

• Checked all cable connections — even a slightly loose terminal can make the voltage drop worse under surge load
• Enabled the PowerAssist feature in VictronConnect — not sure if this applies to your exact setup but worth checking
• Adjusted the dynamic current limiter settings, though I'll be honest I had to ask on here before I understood what I was doing 😅

The other option people suggest is a soft starter device inline with the freezer. Apparently they smooth out that compressor surge significantly. Has anyone here actually tried one with a chest freezer specifically? I've seen them recommended for air con units but wasn't sure if the principle is the same.

Also worth asking — how old is the freezer? At some point an aging compressor gets harder and harder to start, and no amount of inverter tweaking fixes a worn-out motor. Might be worth checking the running current with a clamp meter to see if it's drawing more than it should.

What size Multiplus are you running and what's your battery bank? That might help people give more specific advice.

WattJane | 847 posts | ⚡ Solar Addict

@Julie1991 Classic inrush current headache! One thing worth trying if you haven't already — enable the "PowerAssist" feature in VEConfigure and also check your transfer switch settings. Sometimes the Multiplus is reacting to the surge before it's had chance to properly assess it.

Also worth looking at a "soft starter" add-on for the freezer compressor — NorthernTool and a few others stock them for reasonable money. Drops that startup current dramatically and completely solved a similar problem on my narrowboat setup with an elderly chest freezer I refused to give up on!

What's your battery bank like? Weak or undersized batteries can make the inverter more sensitive to these spikes too. Worth checking your battery voltage is holding steady under load before throwing money at anything else.

IslandOffGrid | 234 posts | 🏝️ Off-Grid Dreamer

Had this same battle fitting out my shepherd's hut. Old secondhand chest freezer was absolutely flooring my Multiplus every startup — genuinely thought I'd done something wrong with the installation.

What finally cracked it for me was enabling the PowerAssist function and adjusting the AES settings in VictronConnect. The Multiplus has a configurable transfer switch speed that can be softened slightly for resistive/motor loads.

Also worth checking: what's your DC bus voltage at the moment the compressor kicks in? If your battery's marginal, that inrush spike hits harder. I switched to Fogstar Drift LiFePO4 cells and the difference in voltage stability under surge loads was immediately noticeable.

Older compressors genuinely do have brutal startup draw — sometimes the honest answer is a soft-starter like the Micro-Air EasyStart. Transformed my motorhome setup too.

RelayNomad | 412 posts | ⚓ Boat/Cabin Dweller

Worth checking whether your Multiplus is actually configured with the correct PowerControl settings in VEConfigure — a lot of people leave the AC input current limit set too conservatively, which compounds the inrush problem even when shore power isn't involved.

Also, old chest freezers vary massively on startup draw depending on how knackered the capacitor on the compressor is. Ran into this on the cabin — same freezer, same inverter, fine in summer, tripping constantly in winter when the compressor was working harder against a cold ambient start. Replaced a £4 run capacitor and the problem vanished.

Before spending anything on soft starters or newer kit, I'd at least check that capacitor first. It's a five-minute job and easily overlooked.

ThistleTel | 1,203 posts | 🔌 EV & Off-Grid Nerd

Something nobody's mentioned yet — check the PowerAssist settings in VE.Configure. If you're running the Multiplus off a battery bank that's even slightly undercharged, the inverter's DC input low-shutdown threshold can interact badly with compressor inrush, essentially collapsing before PowerAssist can compensate.

Also worth looking at the AC output current limit setting specifically. I've seen installs where this was left at a conservative figure from initial commissioning and forgotten about entirely.

On my own setup I run an old chest freezer alongside EV charging loads — the key fix was actually a soft-starter module (ICM Controls do decent ones, or search for Sprecher+Schuh). Dropped my compressor inrush from ~65A spike to under 20A measured on my Victron BMV. Completely transformed reliability without touching the Multiplus configuration at all.