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

Had this exact issue last summer with my cabin setup. Old chest freezers have a massive inrush current when the compressor kicks in — can be 5-6x the running amps for a split second. The Multiplus doesn't always love that.

Few things that helped me:

• PowerAssist — worth checking if it's configured properly in VE.Config
• AC input current limit — if it's set too low the unit panics on that spike
• Transfer switch speed — mine was set aggressively, caused grief

Also depends which Multiplus you've got. The 12/1600 I had on the boat struggled way more than the 24/3000 I moved to later. Older freezers with worn compressors draw even more on startup too, worth bearing in mind.

Honestly might just be the freezer itself. Stuck compressor or low refrigerant can make the inrush worse. A soft starter like a Micro-Air EasyStart or similar can make a huge difference if you don't want to replace the freezer — fitted one to an old fridge at the cabin and the inverter barely notices it now.

What size Multiplus and what freezer roughly? Someone here will probably recognise the combo. Also worth pulling the VE.Bus error logs if you haven't already — tells you whether it's actually an overload trip or something else going on.

Wendy1968 | 847 posts | ⚡ Solar Addict

@Fogstar_Fan makes a good point about inrush current. One thing worth adding — the age of the compressor matters enormously here. Older units often have worn start capacitors which make that inrush spike even worse than it should be.

Before assuming it's purely an inverter sizing issue, I'd check whether your freezer has a start relay or capacitor that might need replacing. Sometimes a £4 part from an appliance spares site sorts the whole problem out and the Multiplus stops tripping entirely.

Also worth enabling the PowerAssist feature if you haven't already — though honestly with a tired old compressor motor, the real fix is usually mechanical rather than fiddling with inverter settings. What model freezer is it? Someone here will likely know its specific quirks!

PanelGraham | 1,243 posts | 🔋 Battery Nerd

Worth checking your PowerControl and PowerAssist settings in VictronConnect — sometimes the transfer switch threshold is set too conservatively and it interprets that inrush spike as an overload before the Multiplus has chance to react properly.

Also, what's your battery setup? A undersized or high-internal-resistance bank will sag under that inrush, which compounds the problem. Happened on my narrowboat with an older AGM bank before I switched to Fogstar Drift lithium — night and day difference.

One practical trick: a soft starter on the freezer compressor. Relatively cheap, cuts inrush dramatically. ICM controls do decent ones.

Check your event log in VictronConnect too — it'll tell you whether it's tripping on overload or low voltage, which points you in completely different directions for the fix.

GemmaCooper86 | 312 posts | ☀️ Off-Grid Enthusiast

Had this exact problem with my static caravan last year — old chest freezer nearly had me pulling my hair out. What sorted it for me was a soft starter fitted to the freezer compressor. Dead simple fix, picked one up for about £30. Dropped the inrush massively and the Multiplus stopped complaining overnight.

Also worth checking your battery state of charge when the freezer kicks in — if your cells are low, the voltage sag under that inrush is worse. I've got Fogstar Drift cells and even they struggled until I sorted the soft starter.

@PanelGraham's point about settings is valid too, but I'd try the hardware fix first before diving into config changes.

OldSailor | 2,891 posts | ⚓ Salty Sparks

Old compressors don't just have inrush — they have ancient, clapped-out capacitors that make it even worse. Worth fitting a soft starter (NVT or Microcare do decent ones) between the Multiplus and the freezer; I dropped my compressor inrush from ~47A to under 12A measured on my Victron BMV-712. Also check your AC Out 2 vs AC Out 1 configuration — if that freezer's on a non-critical output, the Multiplus will shed it under load rather than trip entirely. @PanelGraham is right about PowerAssist, but realistically if the inverter's tripping rather than just struggling, your transfer switch timing settings in VE.Configure might need a look too. A £25 soft starter is usually cheaper than the headache though.

CamperJackie | 487 posts | 🚐 Van Life → Static Life

Oh this takes me right back — I had exactly this drama when I first started using my Multiplus for EV charging coordination at the static caravan. Completely unrelated load, but same lesson learned the hard way: the Multiplus isn't being dramatic, it's doing its job properly.

What sorted mine was adjusting the low battery trip threshold first, because the voltage sag during inrush was fooling it into thinking something catastrophic was happening. Worth ruling that out before anything else.

Also — and @OldSailor will probably agree — sometimes the honest answer is that a 30-year-old compressor just isn't compatible with modern inverter tech without a soft-starter fitted. The Victron ESS isn't magic, it can only work with what the load demands of it.