Is this a correct wiring diagram?
(especially AC Out-2 not used)
No. 
A lot more information would be needed. But it if youâre asking can you use a 230V MPII between Phase L1 and Neutral and run some loads off of an AC out, yes, as long as you follow the guidance in the manuals and the wiring guidance Victron provides.
It might be a good idea to meet with a professional electrician that knows Victron and related equipment. Youâll probably want an Ekrano GX or Cerbo GX in there, and more.
That will work fine, but as said you need more parts than just the mp2 and a battery
Instead of a separate gx you can use a mp2 gx, a grid meter would also be my advice
If the objective is purely critical loads, effectively a UPS, since you have no PV, a grid meter would be an expensive piece of equipment that wonât add any benefit as you wonât be backfeeding power.
Of course if you do have PV and want to offset some loads on the other phases then a meter would help, or if if you have some parallel loads on L1 you want to cover, a CT is a cheap option for single phase.
Again, neither required.
Definitely a GX for management and visibility via VRM.
I have run a single phase multi pair for ages on a 3-phase supply, though powering all the loads. Works like a dream.
It doesnât have to be on L1, you could wire it into any of the 3 phases, since it has no clue what phase it is actually on.
I have a similar setup, but in a single phase system. Itâs working fine.
Something to consider is that for the few seconds after the grid is restored (after a power cut), the two sets of L1(direct from grid and ACout1) will be live in the system but not yet synchronised.
For this reason Iâve been careful to keep those two sets of wiring well separated.
A power cut will become less noticeable around the house. VRM can send a message on Loss of Input, but if an RCBO trips on a critical circuit (like a fridge or freezer) itâd be good to be notified of that too. I installed contactors on those circuits and connected the slave contacts to the digital inputs of my GX so that I could set up a messaging rule in VRM.
You might also want to install some more PV via an MPPT direct to the battery in order to increase your endurance when the grid is down.
I certainly wonât do it myself and leave it to a skilled electrician. And I am fullly aware more equipment must be used.
But I want to understand the principles.
Unitil now I have not found an officiual diagram that is âsimpleâ enough for me to understand.
At first I made the pricture below, but now think AC OUT-2 will never be used.
( picture removed tho avoid confusion)
A load wil either be connected to AC OUT-1 or to the normal L1, so I suppose there wonât be a problem like you warned me for.
I have tought (a little bit) about changing my PV tot an MPPT, but think that is too expensive for me.
Unitil now power outages are seldom and short.
Rather than hoping for PV (during longer outages), I am now thinking to load the battery via the V2L of my car,
There is PV (the âzonnepanelenâ in the picture).
And a grid-meter (and GX and go on) will certainly become part of the installation.
Installation will be done by a certified installer (I am in a quotation process), but I want to understand the principles.
I havenât found an official Victron diagram yest.
Glad to hear that you have good experiences with this situation.
Add a cerbo GX and a gridmeter (VM-3P75CT) and cables this works fine.
If Grid-network is off, your 3Phase PV-Solar inverter wil also be off. zo this is only a UPS solution, with a peakshaving on L1.
With a PV inverter you would want this configured so the inverter can control it and be aware of what is being produced. Your installer will know how to do this.
You are correct, but Iâm only giving a heads-up that for a few seconds when grid power is restored you will have two unsynchronised AC sources. So you need to take care that there is no wiring link between them.
After those few seconds, the MP2 will have synced to the grid and the issue goes away 
Thatâs a great idea to load the house battery from your EV during a power cut. eg. LiFePO4 Charger (Fogstar Energy) - 48V 35A
They are completely isolated outputs. Else you would be looping AC out to AC in.
Not sure how synchronisation is an issue in the topology drawn above.
in which country do you live? Or more precisely does ânet meteringâ apply or is every phase measured independently?
If net metering apply like in Germany, then a single MP2 can store surplus PV into the battery and serve all your loads from billing perspective during grid operation. This is named âESSâ with net metering or âsum of all phasesâ.
In case of grid failure, the single MP2 will serve only the circuit on ACout.
If you are integrating this into an existing maybe older building, main issue will be the circuits spanning several rooms. So you might not be able to separate the critical loads from all loads without adding new circuited throughout the entire building.
In any case you have to ensure the critical loads are only connected either to ACout or to the grid, never both. Furthermore the one-phase circuit with critical loads shall not include 3-phase loads.
This was the main reason I decided to go with 3x MP2. Fridge, freezer, IT and heating system have been on separates circuits, which have been on different phases and reused for several rooms. No chance to put them on a single circuit.
The most economical solution is a grid-parallel MP2 or Multi RS 230 and a small distribution panel with CEE and EU plugs on ACout. In case of grid failure you take your blue CEE camping cord to the fridge.
The other end is a 3-phase system (3x MP2 or Multi RS) and the whole house including your three-phase PV on ACout.
During grid failure, the Victron gear will create a micro grid (island, offgrid) and your PV inverter will charge your battery.
Putting the wall box on ACout2 or grid-parallel (ACin) is a flavor. ACout2 can be programmed based on SOC.
Hello Björn
I live in the Netherlands.
For me it was an eye-opener that there is a thing called âphase nettingâ (I donât know if this is the correct transalation of the Dutch word âfasensalderingâ)
Simple example: L2 and L3 both use 2 kW. L1 asks nothing,
Now the MP2 pushes 4 kW back to the grid (via L1).
The nett result for the grid is 0, so no costâŠ
At least: that is how I understand it.
Suppose I have enough power in my battery, then only when my total house (over all my phases) uses more than 4 kW (the maximum a MP2 can produce) I have to pay.
That is very seldom the case.
And if so: I donât care that so now and then I ask power from the grid.
I donât aim for an âoff-gridâ house.
And for charging the battery: when I have plenty of PV-power, one MP2 can charge the battery with 4 kW and on a summerday there is enough time to fully load the battery.
When there is less surplus PV-power (letâs say less than 4 kW), a second (or third) MP2 would not help to load the battery quicker.
So: in my house I see no good reasons for 3 MP2âsâŠ
About the circuitry:
I have a modern house and there are only a few circuits (with e.g. the freezer) that I want to have power during an outage
⊠Furthermore the one-phase circuit with critical loads shall not include 3-phase loads.
I understand that, and hope my picture was clear about this.
.. In case of grid failure you take your blue CEE camping cord to the fridge.
I understand.
But for now I am aiming tot load the battery via my V2L (in case of an outage).
I plan to always leave 3 kWh in the batterry. In case of an outage that gives me a few hours to act (my critical load is less than 1 kW),
Normally spoken there is at least some 30 kWh in the battery of my car. I use a charger to bring power from my car to the LiFePO4 battery. Letâs say 10 kWh in 3 hours. This buys me another 10 hours time.
Then I unplug the charger, and drive my car to the nearest fastned-station that has power. There I quick-chartge my car until 50 kWh and go home again. Fill my battery.
Easy does it
⊠Putting the wall box on ACout2 or grid-parallel (ACin) is a flavor. ACout2 can be programmed based on SOC.
I hear that this is not as simple as it sounds. Most people advise for a LiFePO4-charger.
Ofcourse I understand that 3MPâs is better.
For example during power-outage you can power 3-pase equipment.
But: it is a lot more expensive. And until now power-outages are seldom and not very long.
Hi @pesmi30
according Google Netherlands use â intern salderenâ, though feeding back on L1 is summed up with usage on L2 & L3.
In this case one MP2 is perfect. Normal load is 300-500W for a house.
With the energy meter VM-3p5ct directly after you grid meter, your MP2 tries to keep 0 watt net over all phases. Surplus PV goes to battery, all loads will be supported from battery.
ESS setting is âall phasesâ.
In ESS you can define a âminimum SoC until grid failedâ. The system will keep that amount of energy in the batteries.
Everything works automatically.
Do not forget earthing and RCBOs for the critical loads circuits.
Pls read about the humming of MP2 and isolation. Maybe the new Multi RS 230 is an option.
In my opinion, a single-phase Victron system is perfectly adequate for most households. Apart from details like the GX device, grid meter, fuses, etc., your wiring diagram is completely correct. The most important basis for planning is your householdâs load profile.
If you havenât yet purchased the three-phase PV inverter and solar panels, I would advise against it; instead, I would charge the majority of the solar yield into the battery using Victron SmartSolar MPPTs. However, using one or two small microinverters to cover the base load makes perfect sense.
An electric car can also be charged very effectively on a single-phase 230V supply; with a charging power of just 2 kW, you can add over 100 km of range every night. That is more than double the daily driving distance of an average passenger car in the Netherlands or Germany.
I wouldnât worry too much about powering the heat pump, as it consumes the most electricity precisely when solar output is insufficient to supply the house anyway. I installed a very similar Victron system myself in Germany. Here, DIY installation is generally permitted, provided the system is inspected and registered by a certified installer, who then connects it to the grid and commissions it. However, I am not familiar with the legal regulations in the Netherlands.
Thank you.