Generator unlatches from Quattro, explanation required

Been having a similar head-scratcher with my van setup, though on a smaller scale — Quattro 24/3000 rather than the big 10kVA unit.

I've got a Honda EU22i feeding into AC1 input, and every so often the Quattro just drops the generator mid-charge. No fault code that makes obvious sense, charge is nowhere near complete, generator sounds absolutely fine. It's not overloaded. It just... unlatches.

A few things I've been looking into:

• AC input current limit set too low in VEConfig — the Quattro briefly pulls more than the limit allows and drops it
• Dynamic current limiter — anyone actually found this helps in practice?
• Generator frequency drift — the Honda can wobble a bit under load and apparently the Quattro is quite fussy about this

Has anyone with a larger system (sounds like the OP over on the other thread had 10kW solar and Pytes batteries involved too) found that the state of charge on the batteries affects when this happens? I wonder if a nearly full bank causes the Quattro to behave differently when arbitrating between sources.

I've been through the Victron community forums and there's a lot of conflicting advice. Some say raise the input current limit, others say lower it so the inverter has headroom.

Would genuinely love to hear from anyone running a generator alongside solar and a large battery bank — whether that's a proper off-grid cabin setup or a conversion like mine. What actually solved it for you?

@Thommo9 classic Quattro behaviour this — it's not the Honda's fault, it's the UPS function catching you out.

When your loads spike suddenly, the Quattro briefly switches to inverter before the generator can respond. If that transition happens while the generator frequency is slightly off (Honda EU22i hunting at light load is notorious for this), the Quattro decides the AC source isn't stable enough and drops it entirely rather than risk a hard synchronisation.

Had exactly this on my static caravan setup last winter. Fixed it with two things:

1. Lower the AC1 input current limit slightly — forces the generator to work harder and stabilise frequency
2. In VEConfigure, nudge the AC low frequency disconnect down to around 45Hz

The EU22i's inverter generator should be clean enough, but mine was marginal on cold mornings before it warmed up properly.

What's your actual load looking like when it drops?

@Thommo9 to add to what @FellKev said about the UPS function — worth checking your AC input current limit in VEConfig or the GX device. If it's set too low relative to what your charger's actually pulling, the Quattro starts borrowing from the battery to compensate, then decides the generator's "too weak" and drops it entirely.

Also check your weak AC setting is actually enabled — Honda inverter-gens produce lovely clean sine wave but the frequency can wobble slightly under sudden load, and if weak AC is disabled the Quattro gets rather snobbish about it.

My own Quattro 48/5000 did something similar with a Kipor until I bumped the AC input limit down paradoxically, forcing it to load the gen more gradually. Sometimes less is more with these things.

@Thommo9 had exactly this on my boat last summer — drove me absolutely mad for three weekends running. Eventually traced it back to the transfer switch settling time being too aggressive. Honda EU22i takes a good few seconds to stabilise its frequency when it first fires up under load, and if the Quattro's "AC low disconnect" voltage threshold is set too tight it'll unlatch before the generator's even had a chance to warm its knickers up.

Worth digging into the "Ignore AC input" timings in VEConfig — specifically the frequency acceptance window. Mine was set to defaults which were basically intolerant of anything slightly wobbly.

Also — is your EU22i running the ECO throttle? Turn that off while troubleshooting. It introduces exactly the kind of frequency hunting that makes Quattros nervous.

@Thommo9 one thing nobody's mentioned yet — have a look at your dynamic current limiter setting in VEConfig. With a small inverter-generator like the EU22i, the Quattro can be a bit aggressive about pulling current during the battery charge bulk phase, especially if your batteries are well discharged. The Honda will momentarily dip in frequency as it struggles, and the Quattro interprets that as a dodgy supply and disconnects.

Enabling the dynamic current limiter tells the Quattro to back off gradually rather than demanding full current straight away — gives the Honda time to respond. Made a significant difference on my setup. Worth pairing that with setting your AC input limit conservatively around 7-8A rather than the theoretical maximum. The EU22i is rated 2.2kVA but realistically you want headroom on a small inverter-gen.