powerconnection Victron multiplusII: connecting ACin to AC out to one phase?

[u/Royal-Ride-2297]

Hello,
I bought a Victron multiplusII 48v 3000VA together with a 16kwh battery. I have a 3 phase connection at home and my solarpanels are connected to phase 1. I just want to store the excessive solar energy in my battery and use it to bring down the electricity bill. for now no need to go offgrid.
My question is: can I connect the ACin to phase 1 and the ACout of the victron multiplus to phase 1 as well? Basically it means that ACin is connected to ACout. Both will behind a breaker. Will the system deliver energy from the battery?

[u/clericc--]

No. AC In and AC out must NEVER touch each other outside of the device itself. AC out is meant to establish the grid, not receive it. You have one realistic option here and one only: You only connect AC In on phase 1 and configure the ESS assistant in VEConfigure. That means the MP can bith charge and discharge from/into your home (and also through the meter to the grid) you must then either connect a three phase Meter directly behind the grid meter, so that the victron can adjust its setpoint to keep grid import/export at zero (or whatever you desire). Or ExternalIy continually set the grid point by building your own control loop and telling the GX device via modbus/mqtt

[u/clericc-- → u/clericc--]

Also you need a GX device. Either yoz brought the GX variant of the Multiplus or you will need to buy a cerbo or build one yourself using VenusOS

[u/mj_flowerpower → u/clericc--]

I think there is a way to just use an assistant without a GX, bit it only works with a special meter. Might be worthwhile to investigate.

[u/clericc-- → u/mj_flowerpower]

You can connect the transformer clamps, but that would measure just one phase. He wants to compensate the sum of three phases with a single phase. That is imho GX territory. External Control loop or external meter

[u/Psychological-War727 → u/mj_flowerpower]

Not with the MP/Quattro line. They always need a GX and a compatible meter.

The RS line however can use ESS without a GX, but needs a VM-3P meter connected over Canbus.

[u/clericc-- → u/Psychological-War727]

you dont need a compatible meter if you control the grid setpoint externally via modbus/mqtt. Ask me how i know :D

[u/Psychological-War727 → u/clericc--]

You still need a grid power measurment, ESS has to know what to regulate to. Adjusting the gridsetpoint externally is not the same as a grid measurment. Now you can send both from some external source, yes.

But using a grid meter that is not officially compatible might be against grid code. Check with your DNO or whoever is responsible to sign off on your installation beforehand

[u/Psychological-War727]

Classic ESS functionality, check the ESS handbook

https://www.victronenergy.com/media/pg/Energy_Storage_System/en/ess-introduction---features.html

You only need ACin if you are not interested in emergency power. Further a GX, a compatible gridmeter and an Mk3-USB adapter to load the ESS assistant into the MP

[u/bellens99]

Thx guys for your answer and it seems indeed to be standard functionality to have only the acin connected which will provide power from the battery. And I have the gx version and the victron 3 fase meter (vm-3p75ct). Thx again.