I have the following existing installation in my home in Spain (Murcia)
Country: Spain
Grid: Single phase 230 V / 32 A
18 Enphase IQ8P microinverter installation
Enphase IQ Gateway Metered
ET112 Grid Meter
Battery: Future Victron-compatible battery
Home Assistant (non safety-critical)
MultiPlus-II GX
Physical installation
The Main Distribution Board (MDB) (where the Ibedrola cable enters the house) is located inside the house.
The Victron MultiPlus-II GX and battery will be installed in a garage approximately 10M away from the distribution board.
Between MDB and the garage there is already one existing 32 A feeder cable (to feed an EV charger). It is preferable not to add an extra pair 32A cable to feed the house in Island mode from the AC-OUT on the Victron MultiPlus-II GX.
In normal operation:
The system will operate as a standard ESS with the ET112 acting as the Grid Meter. The MultiPlus will charge/discharge the battery according to ESS control.
In MANUAL Island Mode (Automatic transfer is not required).
The system (Victron MultiPlus-II GX) needs to switch over to Island mode and feed the house (via the AC-OUT over the 32amp cable going from MDB to Garage). In order to prevent 220v flowing back into the grid I was thinking of adding the following setup:
The main Isolator (IGA switch) will be equipped with an extra contact which informs Home assistant and the GX OS about the state of the Grid connection (Connected / NOT Connected)
I understand one can create a script in the GX-OS to read out this switch and thus allow/disallow switch over to island mode.
Since there is only ONE 32Amp cable from MDB to the Victron MultiPlus-II GX available it will need to be connected to the AC-OUT in Island mode and to AC-IN in normal mode
For this I think I need an I-0-II switch where its output is connected to the 32AMP cable and its inputs to resp AC-IN and AC-OUT
SO during a longer outage, I will switch off the IGA, Victron MultiPlus-II GX detects this and will allow to manually switch over the MultiPlus-II over to Island mode.
To get the power back on the house I need to switch over the I-0_II switch to AC-OUT (AC-IN is then disconnected)
Is this setup possible the Victron MultiPlus-II GX sollution. Any 2nd thoughts?
From the grid I have a supply to the voltage control relay that controls the 40A power relay. In the event of a power outage, it disconnects the power relay. From there it goes to Multiplus ACin and the whole house is connected to ACout.
Multiplus II has 2 problems. If you don’t want to supply to the distribution, or you don’t have a contract (permit).
1. If it is in island mode on ACin, it generates voltage that the distributor’s electricity meter records as unauthorized supply to the grid. It’s a small power flow but my electricity meter recorded it. (I got a fine).
2. If the ESS mode (SoC limit Off), Multiplus II is ongrid and there is a power outage, Multiplus II automatically switches to BACKUP mode. But this mode does not disconnect the relay on ACin, so ACout and ACin are powered at the same time. In this mode, Multiplus pushes power back into the network and into the house at the same time. For this, I have an auxiliary power relay at the input with power monitoring to eliminate backflow to the distribution in the event of a power outage.
I control one side of the power 40A relay from CerboGX relay1 where the neutral wire is connected. There I have node-red running and I solve the disconnection of cerbogx relay1 based on the ESS status. And at the same time switching multiplus II to offgrid. The other side of the relay coil is controlled by the voltage monitor at the input from the distributor.
And if I understand correctly, you want to push back to the house via acout via a 32A cable. So the distributor switch and multiplus II would be in the house. Keep in mind that the 50Hz synchronization will not be accurate and what happened to me, that the half-waves met and the circuit breaker on the supply line tripped, could happen. For your project, I would rather use ACin rather than ACout to power the house. It can also supply the house as ACout and at the same time you can also charge the battery with the grid. But with this connection, the ESS must have power pushing to the grid enabled. Which is not a good solution when switching via switch 1-0-2. Do you have the option to add another cable to the garage? Otherwise, you will have to deal with tripped circuit breakers and constant outages.
What you want is not a good solution. In your case I would rather divide the switchboard into grid and backup. grid (washing machine, dryer, ceramic hob) all power devices. backup (PC, router, TV …), but even so this does not solve the problem with phasing multiplus II
Incorrect. In the event of a grid failure, the internal AC-in relay is physically disconnected, making it completely impossible to feed power back into the utility grid.
Set the ESS to the SoC limit and disconnect the house circuit breaker. You will have voltage from the inverter on the circuit breaker, which is undesirable for the safety of the inspection technicians.
and if the multiplus acin is connected to the grid and switched to offgrid, it produces a small flow of energy into the grid. I noticed this on the distributor’s electricity meter where there are arrows indicating the direction of energy flow.
You don’t seem to understand how ESS works.
You have to select a grid code, this enforces LOM.
On grid loss the inverter will disconnect from grid.
Dual relays prevent a relay failure from allowing live mains on the input.
This is a certification requirement.
Your comment is factually incorrect.
Your second point is unrelated, it as about the setpoint which ebbs and flows, something you can adjust and is irrelevant in a grid failure or rejection.