Problema con sistema trifásico multiplus-II

Bit of an odd one this — hoping someone with three-phase Multiplus-II experience can chip in.

Inherited a site installation that someone else put together (always fun...). It's a three-phase setup with a pair of Multiplus-II 48/5000s, Victron MPPT controllers, and a 48V battery bank — Pylontech stack if I remember right from the docs left behind.

The issue is that the phases aren't behaving consistently under load. One leg is clearly doing more heavy lifting than the other two, and I'm seeing the VE.Bus system throw occasional warnings that don't seem to correlate with anything obvious — no massive load spikes, nothing tripped, just... grumpy.

A few questions for anyone who's dealt with similar:

• Was the three-phase configuration actually set up properly in VEConfigure? I've been through it and the master/slave assignments look correct, but I'm not 100% confident the previous installer knew what they were doing.
• Has anyone seen load imbalance cause knock-on issues with the MPPT prioritisation between phases?
• Worth upgrading to the latest firmware across the board first before digging deeper?

I'm used to single-phase off-grid setups for EV charging applications so three-phase is slightly new territory for me in terms of fault-finding. The Victron community forums have some useful threads but a lot of them are written assuming grid-tie commercial installs rather than the hybrid off-grid stuff we tend to do here.

Anyone with hands-on experience with this sort of three-phase hybrid headache — would genuinely appreciate the input before I start pulling things apart unnecessarily.

@NQ_Sparks the thread title is in Spanish but your post reads as English — worth clarifying which language you're working in, as the Victron documentation differs slightly between localised versions and some menu paths aren't identical.

That said, three-phase Multiplus-II inherited installs are a particular minefield. The most common issue I encounter is phase rotation being set incorrectly in VEConfigure — it must match your actual L1/L2/L3 physical wiring, otherwise the units won't synchronise properly and you'll get persistent grid code faults.

Before anyone can help meaningfully, can you confirm:

• Firmware versions across all three units (must be identical)
• VE.Bus system configuration tool used (VEConfigure 3 or VictronConnect)
• Whether there's a shared neutral correctly sized
• What specific fault behaviour you're actually seeing

What does the post actually say — it seems to have been cut off mid-sentence.

@DefenderAdventure already flagged the language thing so I'll leave that alone.

@NQ_Sparks — you've cut off mid-sentence so nobody actually knows what the problem is yet. Post the full description and ideally screenshots from VRM if you've got remote monitoring set up.

That said, inherited three-phase Multiplus-II installs are almost always a headache. Nine times out of ten the issues come down to:

• Units not properly configured as a three-phase group in VEConfigure
• Firmware mismatches between the three inverters
• Dodgy VE.Bus cabling between units

Get yourself a MK3-USB adapter if there isn't one on site and check what firmware each unit is running. They all need to match. Victron's documentation on three-phase configuration is actually decent — download the relevant manual from their site before touching anything.

@NQ_Sparks yeah the post got clipped so we're all a bit in the dark about what the actual fault is — finish the description and we'll get somewhere useful.

That said, three-phase Multiplus-II setups inherited from someone else are a particular kind of headache. Done a bit of single-phase Victron work on my static van and even that had quirks baked in from the previous owner's decisions.

Main things worth checking once you've filled us in:

• VE.Bus configuration — are all three units actually talking to each other correctly in VictronConnect / VEConfigure?
• Which unit is set as master?
• Any ESS assistant loaded, and is it consistent across all three?

A lot of "inherited" three-phase installs have one inverter with a slightly different firmware version and that causes all sorts of weirdness.

@NQ_Sparks — echoing what others have said, we genuinely need the full fault description before anyone can help meaningfully.

That said, three-phase Multiplus-II setups are notoriously easy to misconfigure when you've inherited someone else's work. A few things worth checking while you're pulling the info together:

• Are all three units on identical firmware? Mismatched versions cause some really cryptic behaviour
• Is the VE.Bus cabling in the correct master/slave configuration?
• What does VictronConnect or VRM show for each phase individually?

I've not run three-phase myself (motorhome obviously rules that out!) but I've followed enough of these threads to know the devil is usually in the assistant configuration settings within VEConfigure.

Post the full fault description and ideally a screenshot from VRM — someone here will recognise it.

@NQ_Sparks — while you sort the truncated post, one thing worth doing straight away on any inherited three-phase Multiplus-II setup: pull up VEConfigure and check all three units are actually configured as a proper three-phase group (L1 master, L2/L3 slaves) rather than three independent single-phase units. Seen this catch people out more than once.

Also check the VE.Bus firmware is identical across all three — mismatched firmware on a three-phase stack causes all sorts of weird behaviour that can look like hardware faults.

Once you've posted the full description I can probably narrow it down further, but those two checks are quick wins while you're waiting for replies.