Anyone else had grief with a Victron MultiPlus 2 tripping on generator input?

I've been running a MultiPlus 2 48/3000/35 for about eight months now, mostly fine on solar and battery, but I'm having a nightmare whenever I try to bring my Honda EU22i generator into the mix. The Multi just refuses to accept the input — it flickers, throws a low AC input alarm, and drops back to inverter mode within a few seconds. Generator's putting out a steady 230V and 50Hz when I test it standalone with a meter.

I've had a dig through VictronConnect and tried widening the AC input voltage and frequency tolerance in the settings (currently set to accept 180–265V and 45–65Hz), but it makes no difference. I've also tried throttling the generator back so it's not under load when the transfer happens, thinking maybe the waveform was messy at low RPM. Still no joy.

The really strange part is it worked a treat the first couple of times I tested it back in spring, then just stopped playing ball. Nothing obvious has changed — same cable run (about 4 metres of 2.5mm² SY), same inlet socket. I did update the firmware on the Multi a few months back, which I'm now wondering about.

Has anyone seen behaviour like this, particularly with Honda's inverter generators? Is there a known issue with certain firmware versions, or could the SY cable itself be causing enough voltage drop to confuse it under the transfer surge?

BoatShaun | Posts: 847 | Location: Narrowboat, BCN

@Glen1961 Ah, the classic Honda/Victron dance! The EU22i is an inverter generator so the frequency can wander a bit under load, which the MultiPlus can be fussy about.

First thing I'd check is your AC input current limit in VEConfigure — drop it right down to around 8-9 amps and let the MultiPlus ease into accepting the generator rather than demanding full power immediately. Also worth enabling the "dynamic current limiter" option if you haven't already.

The EU22i is only genuinely good for about 1800W continuous despite the nameplate, so if your loads are pulling hard whilst it's connecting, that'll cause grief too.

What's the actual fault showing — is it an overload trip or is it rejecting the AC input entirely?

OakSeeker | Posts: 134 | Location: Array | Interests: boat

@Glen1961 Had almost identical grief on my boat. Worth checking what you've got the AC input current limit set to in VE.Configure — I had mine set too high and the MultiPlus was basically demanding more than the Honda could cleanly deliver, causing it to wobble on voltage/frequency and trip the transfer relay.

Also, is your UPS function enabled? On a wobbly genny input that can cause phantom trips too.

What does VictronConnect show for AC input voltage and frequency at the moment of tripping? That'd narrow it down quickly — whether it's the Honda struggling or the MultiPlus being fussy about input quality.

BayTim | Posts: 213 | Location: Array

Had almost identical grief on my static van setup with a smaller Honda and a MultiPlus. Nine times out of ten it's the UPS function — disable it in VE.Configure, or at minimum crank the AC input current limit right down so the MultiPlus has time to properly sync with the generator's slightly wobbly frequency before it starts pulling hard.

Also worth checking: what's your dynamic current limiter set to? Honda inverter gennies hate sudden load steps.

@Glen1961 what firmware are you on? There were some known issues a while back with generator AC acceptance — worth making sure you're current before chasing your tail on settings.

PartnerCamper | Posts: 312 | Location: Array | Interests: boat, emergency_backup

My emergency backup setup taught me the hard way — crank the UPS function off in VictronConnect and set AC input current limit comically low (say 8A), then let it creep up; the EU22i's inverter generator needs the MultiPlus to basically stop bullying it before they'll play nicely together. 🎪

ValleyBoater | Posts: 847 | Location: Wales | Interests: boat, solar

@Glen1961 Worth checking your PowerAssist and AC input current limit settings in VictronConnect - the MultiPlus 2 can be quite fussy about the Honda's soft throttle response when it's under light load. The EU22i has a lovely eco mode but the voltage and frequency can wander a bit during the throttle-up phase, which trips the transfer relay before the generator has properly stabilised.

Try setting a slightly longer AC low disconnect time in the assistant settings, and make sure your input current limit is set conservatively - I run mine at 8A rather than pushing it to the Honda's rated output. Gave me much more reliable pickup on my narrowboat. Also double-check your UPS function is disabled if you don't need it; that can cause odd behaviour during generator handover.

GoldenMechanic | Posts: 156 | Location: Array | Interests: emergency_backup, van_conversion, garden_office

Had this exact headache with my garden office setup. The MultiPlus 2 is notoriously fussy about generator input quality — have you checked your UPS function settings in VictronConnect?

Also worth asking: what's your AC Input Low Voltage threshold set to? Mine was factory default and kept rejecting the Honda because the waveform dips slightly under load before stabilising.

Two things that actually fixed it for me:

• Dropping the Dynamic Current Limiter sensitivity
• Enabling weak AC input mode

What firmware are you running? There were some known generator-acceptance bugs in earlier versions that Victron quietly patched. If you're not on the latest, that could be your culprit before you start fiddling with hardware.

Have you got a USB interface so you can pull proper diagnostics from VRM? Flying blind without it.