Adjust AC input on Multiplus ii when trigger event

Same situation on my narrowboat — Victron Multiplus-II 3000 hooked up to a Honda EU30i genny, and I'm forever playing the "don't trip the genny" game when shore power isn't available.

The thing is, the Multiplus is perfectly happy hammering away at full input current when I'm on marina shore power, but the moment I'm running off the Honda, I need to dial the AC input limit right down or the poor thing starts having a wobble.

What I've landed on is using Node-RED on a Cerbo GX to watch which AC input is active, then automatically push a new ESS AC input current limit value via MQTT when it switches over. Bit of faff to set up initially, but now it's completely hands-off — genny fires up, limit drops to 13A, shore power resumes, limit goes back to 30A.

You can do it more simply with VEConfigure profiles if you're not fussed about full automation, but that requires physically swapping profiles each time which rather defeats the purpose.

Anyone else doing something similar with a Cerbo or even a Venus OS on a Raspberry Pi? Curious whether there's a cleaner way I'm missing — knowing this forum, someone's already done it in half the steps with a bit of Node-RED wizardry I haven't stumbled across yet. 🤔

Also worth noting for anyone on a narrowboat or shepherd's hut setup: if your genny is undersized relative to your Multiplus rating, sorting this early saves a lot of grief.

@FETFan snap — almost identical setup here on my boat! One thing that's made a real difference for me is using Node-RED on a Cerbo GX to dynamically adjust the AC input current limit based on what the genny's actually doing.

Basically I monitor the AC input frequency — when the Honda starts to bog down (frequency drops below ~49Hz), Node-RED triggers a reduction in the input limit via the com.victronenergy.vebus service. Gives the genny breathing room before it trips.

Worth asking though — are you using the VEConfigure power assist settings at all? I found getting the transfer switch thresholds right was half the battle before I even got into automation.

What's your typical load when it trips? Wondering if it's a startup surge or sustained draw that's catching you out?

@CornishBoater beat me to the Node-RED mention so I'll add some colour from my own experience.

The bit that changed everything for me was setting up a scheduled assistant on the Multiplus-II alongside the ESS — when the Cerbo detects the genny running (I monitor it via a current clamp on the AC input), it automatically drops the input current limit right down to about 10A, leaving headroom for the genny to breathe rather than choke.

The Honda EU30i is surprisingly tolerant but push it into that overload zone and you'll hear it hunting — not ideal at 2am on a mooring with neighbours close by.

One gotcha: make sure your VE.Configure transfer switch settings aren't fighting your automation. Took me an embarrassing afternoon to figure that one out. The Victron community forums have a solid thread on genny-aware current limiting if you search "generator assist."

Great thread — narrowboat life really does sharpen your appreciation for generator management!

To add to what @CornishBoater and @TomCampbell have mentioned, one thing worth considering alongside the Node-RED approach is setting up the ESS assistant with a dynamic current limit tied to your battery state of charge. So if the batteries are reasonably topped up, the Multiplus naturally draws less from the Honda anyway, giving you that buffer before anything trips.

Also worth checking your EU30i's eco-throttle behaviour — mine would sometimes struggle with sudden load spikes even within its rated capacity. I found disabling eco-throttle when running the Multiplus made the whole system far more stable, at the cost of a bit more fuel.

The combination of both approaches — smart current limiting and a steadier generator output — has made a genuine difference on my setup. Happy to share specifics if useful!

Great thread! One thing I'd add that nobody's mentioned yet — have a look at the AC input current limit setting via the VRM portal if you're connected remotely, or just through the GX device directly. You can adjust it on the fly without any automation at all, which is handy when you know you're about to run the kettle and washing machine simultaneously.

Also worth checking your Honda's actual usable wattage rather than peak — the EU30i is rated 2.8kW continuous if I recall correctly, so setting your AC input limit around 10-11A gives you a sensible buffer before the Multiplus starts stealing from the batteries.

@TomCampbell's Node-RED approach is the proper solution long-term, but manual adjustment kept me sane while I was getting everything configured! 😄