I have a 3-phase-ESS, where one Multiplus is currently broken, so the whole ESS is down. Not a big problem as I also have a bypass switch.
However, there’s a state of emergency in my province ATM due to rain and storm, so I’d rather be prepared.
So, can I just configure the remaining 2 Multis as standalone, while keeping the AC cabling untouched? Of course that’d only provide power to 2 phases of my house, but that’s still better than 0. I have no 3-phase loads.
If I can do that, can I keep both Multis on the same VE.Bus and my GX device will just show them as two units?
Quick update: I have now reconfigured the two remaining multis to 2-phase/240° and am running the ESS with all loads and the PV on AC-In, which seems to run fine and currently charges the batteries with the PV excess.
In case of a grid outage, I would have to manually switch over the bypass switch and live with the fact that I only have 2 phases available.
My thoughts behind this are that while I could connect the AC-In cabling of the missing multi to AC-Out and have my house on AC-Out, that’d probably be dangerous in case of a grid failure as there would be no clean separation.
Also, what would be the right choice, If the Phase 1 unit died?
Configuring unit 2 and 3 as a “splitphase 120” would cause display issues I assume, cause “new unit 1” is actually running on phase 2, but probably data is matched with meter/ pv values on phase 1?
Can you run a “splitphase 120” on phase 2 and 3 at all, or will the system always assume that the first unit is phase 1?
I can enlighten as far as: with L1 and L3 remaining, “2 phase 240” works and the units sync to the grid (I didn’t try how “2 phase 120” would behave).
They do show up as “L1” and “L2” in remote console (under the multi details). Some of the numbers there (e.g. the power reading of L3 under “AC loads”) are off, but (with multi-phase regulation active) the ESS nicely brings my grid meter to a true zero reading.
It will technically the master will run as L1 regardless of the phase it is on. And they always run in master follower format. I have not tried it personally.
But the meter will read or show it differently i guess?
Is the AC PV three phase or three single phase units? That will also fall away as well with a missing phase.
The phase angle is what ever phases they are on. I have seen one poorly configured (as in 180° out on a three phase). Connected to grid they are correctly angled since it is synchronised, but inverting not. They system had run for years like that with just a tonne of overload warning/alarms on grid connect and disconnect. (Don’t recommend it).
I am assuming you don’t have actual three phase loads here. Since obviously that’s really what will be affected.
Which is kind of … bad. This will totally mix the pv inverters, loads and even grid meter readings on phase 3 with the inverters power beeing reported as phase 2…
Imho, there is the option missing to configure the phase for the FIRST unit.
If that would be a seperate config-value (during setup) then all other phase/unit allocations could be computed correctly.
Even in the case of using splitphase 240 - what kind of system should that be to assume “L1 and L2” for the units? 3rd, unmanaged phase at 480°?
I agree it is weird, or unexpected, but it’s not really affecting anything critical – with multiphase regulation set to “total of all phases” at least.
I’m currently (with the grid present) running everythng on AC In (PV, grid, loads) and ESS does grid setpoint regulation just fine while charging and discharging, despite the phase name mismatch – it needs power values for all phases for the grid meter and not just a total, or it will stay in Passthru, but those phase power values can just be “total_power/3” with no ill effects.
The “energy counters” on dbus/MQTT are correct, so the totals in VRM also are good, as is my local energy management.
The only thing that’s off seems to be “AC Loads” calculation – the GX overview generally shows L1, L2 as 0 and L3 with the same number as the total, while VRM shows higher numbers that I still haven’t understood where they come from.
Out of curiosity: what are the options “L2&L3 floating” and “L2&L3 floating, return to original phase” for in VE.Bus System Configurator?
To your questions: the PV is three phase, it will probably not synchronize when the grid is gone. Oh well, I have 560Ah of batteries and grid repairs are usually pretty quick here (The last time it took them 45 minutes on a saturday evening).
The only three phase load I have is the EV charger, but that can be switched to single phase.
They can handle three phase rotation on the incoming when floating. Otherwise the whole system rejects grid and remains inverting. Its a useful feature but obviously not applicable to all systems especially where rotation matters.
