Anyone else had issues with Victron MultiPlus-II tripping on high loads?

Running a MultiPlus-II 48/3000 with a 16kWh Fogstar Drift LiFePO4 bank and it keeps tripping when I fire up my workshop compressor (about 2.2kW startup surge). Inverter's set to 3000W continuous so I'd expect it to handle it, but nope — cuts out within seconds every time.

Checked the DC cabling and it's all 70mm² with decent Anderson connectors, so I don't think it's a voltage sag issue. Assistant switch is off. Wondering if it's the overload trip threshold in VE.Configure that needs tweaking, or if the compressor inrush is just hitting too hard even for a 3kVA unit.

Anyone dialled in their overload settings for motor loads? Feels like there should be a way to give it a bit more headroom without voiding the warranty or cooking anything. What settings are you running?

Your compressor's startup surge is probably hitting 4-5x the running wattage, so your 3000W inverter is seeing somewhere north of 8kW for a split second — the MultiPlus-II 48/3000 only does 6kVA surge, mate, it's not magic. 🔧

Check your AC input current limit and overload trip delay settings in VictronConnect — bumping the trip delay slightly can save you from nuisance trips on motor loads. Alternatively, a soft starter on the compressor (ring Bimble Solar, they stock decent ones) will knock that inrush right down without needing to upsize the inverter.

Had the exact same battle with my motorhome's inverter running a angle grinder — soft starter sorted it completely.

Hey @Wayne1980, worth checking your PowerAssist and AC input current limit settings in VictronConnect — sometimes the inverter's overload trip point gets configured quite conservatively from the factory. Also have a look at your Low Battery Shutdown voltage threshold; if your BMS is momentarily drooping the bus voltage under that surge load, the MultiPlus can interpret it as a battery protection event rather than a true overload trip.

What's your battery cabling like? Undersized or long runs will cause voltage sag that compounds the problem. I had similar grief with a motor load until I dropped my cable resistance significantly.

Lastly, consider whether a soft-starter on the compressor motor is an option — they're not expensive and can cut that startup surge dramatically without needing to upsize your inverter.

Hey @Wayne1980, one thing worth looking at that hasn't been mentioned yet is your battery cable sizing and connection quality. Even with a healthy 16kWh bank, if your cables are undersized or you've got a high-resistance connection somewhere, the voltage will sag badly under that compressor surge and the MultiPlus-II will interpret it as a low battery condition and trip on undervoltage rather than overload. Check your BMS discharge current limit too — Fogstar Drift packs have configurable settings and it's worth confirming yours is set high enough to actually deliver the peak current that surge demands. Also, what's your DC fuse/breaker rated at between battery and inverter? Sometimes people fit conservative protection that's nuisance-tripping before the inverter even gets a chance to ride through the surge.