Multi RS 6000, inverter op AC out 2?

Running a grid-tie inverter on AC out 2 is one of those ideas that sounds brilliant at 2am when you're staring at your Victron dashboard and wondering why you're not squeezing every last watt out of life.

On my boat I've been tempted to do something similar — basically using AC out 2 as a "dumb loads only when grid is present" zone, which is exactly what Victron designed it for. The moment shore power drops, AC out 2 goes dark, so anything connected there dies with it. For a grid-tie unit like a GoodWe that needs a reference grid signal to sync against, that's actually the correct behaviour — it won't island and start doing something mad.

The real question I'd be asking is whether the Multi RS's AC out 2 provides a clean enough reference signal for the GoodWe to lock onto during normal grid-connected operation. Anyone actually measured the waveform quality coming off AC out 2 under load? My gut says it'll be fine but I've been wrong before (RCD incident of 2023, we don't talk about it).

Also worth flagging for UK folks — your DNO notification requirements under G98/G99 don't care that you've got it tucked behind a Victron, the GoodWe still counts as an export device if there's any path back to the grid.

Has anyone in the UK actually run this setup successfully? Feels like there's a gap in the Victron documentation that someone's inevitably filled with either a working system or a very expensive lesson. 🔥

@Cerbo_Master ha, the 2am dashboard rabbit hole is real 😅

Worth knowing that AC out 2 on the Multi RS is unswitched — it's live whenever the unit is, so no "ignore AC input" tricks to play there. A grid-tie inverter feeding back into it could get very messy very quickly with islanding protection. The Multi RS isn't really designed to manage that situation cleanly.

What are you actually trying to achieve? If it's just maximising solar harvest, the RS has pretty decent MPPT built in already. Might be worth checking your charge parameters first before bolting on more complexity.

Had a similar "brilliant idea" moment with my shepherd's hut setup — ended up keeping it simple and just upsizing the panels instead.

@AnneWatson beat me to the unswitched bit but worth adding — the Multi RS AC out 2 is really just meant for non-critical loads, not for feeding power back into the system via a grid-tie inverter. You'd basically be creating a feedback loop that the Cerbo wouldn't know how to handle properly.

Had a similar idea for my static caravan setup last summer, got talked out of it pretty sharpish on here 😅

If you want to maximise yield, proper MPPT via Victron SmartSolar is a cleaner solution. The ESS assistant on the Multi RS handles the whole picture much more elegantly than trying to bodge a grid-tie onto AC out 2.

So basically AC out 2 is the electrical equivalent of that drawer in your kitchen that just has random cables and batteries in it — technically useful, practically a mess waiting to happen?

Genuine question though — has anyone actually tried running a small grid-tie on it and logged what happens in VRM? I keep staring at my Multi RS setup in the motorhome thinking *surely

@Cerbo_Master the real problem nobody's mentioned yet is that grid-tie inverters want to see a stable grid reference to sync against. AC out 2 on the Multi RS isn't providing that — it's passthrough when grid's present, dead when it's not. Your grid-tie unit will either fault out or behave unpredictably depending on its anti-islanding protection.

Spent an afternoon last winter tracing exactly this nonsense in my van backup setup before I understood what was actually happening. The Victron documentation buries this in a footnote somewhere around page 47 if memory serves.

If you want meaningful grid-tie integration, look at AC-coupled arrangements on AC out 1 with proper frequency-shift control configured through VEConfigure. That's the supported path. Anything else is just asking for grief.