MP2 AC Coupling

DIY
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21

Sure,

BTW I finally received the Technician Access for the VRM

Screenshot_20251222-132904
Screenshot_20251222-132904847Ɨ986 42.6 KB

Will config AC coupling soon !!!

22

Nice but if youā€™re configuring it on the output obviously it would need to be wired onto the output side rather than the input. And donā€™t forget the meter to monitor the output of the solar inverter, PS make sure you test the frequency shift works before leaving it after config

23

Learn something from my experience and from this answer:

My system initially had just a Fronius Snap inverter, no batteries, with grid export of the production excess.

  • Iā€™ve added a Victron inverter, and Iā€™ve connected the Fronius Snap inverter to the AC output of the Victron Multiplus II.

  • Iā€™ve changed the country code on Fronius to Microgrid 50Hz

  • Iā€™ve made the Modbus changes on Fronius (now all, see below), I could see the Fronius smartmeter on Victron (there is still no other smartmeter on the system). The smartmeter is in front of any other consumers, on the AC-IN of the Victron.

  • Iā€™ve added seven 16kWh LV batteries to Victron (112 kWh) with JK BMS v19 and communication to Victron via CAN.

  • The system worked PERFECT for about a month, then I got a lot of ā€œovercharged cell protection errorsā€ on batteries, one by one = BMS will cut the charging.
    It was a very sunny day.

  • After a lot of hair-pulling, Iā€™ve discovered the problem: Iā€™ve forgotten to activate the ā€œInverter control via Modbusā€ option on Fronius, so Fronius was not stopping even if the Microgrid option was active.

  • Iā€™ve activated the Inverter control via Modbusā€ option on Fronius, and all is good now.

So, I believe that as Victron supports AC passthru, for a grid-connected Victrons, the simple AC Coupling (without modbus control) will not work, as Victron cannot have one frecvency on input and another on the output.

This is not a problem for UPS inverters like Deye, but they do not have AC-passthru.
You can have AC Coupling on the output of any Deye LV without grid communication, but you are limited to Deyeā€™s maximum power for the AC output.

snap_modbus
snap_modbus1570Ɨ1116 133 KB

Later edit
It seems that Victron fixed the issue when you are grid-connected with the Victron and use an AC Coupled inverter on AC Out.
It needs a Victron Smartmeter between the Victron and the AC Coupled inverter so that it can measure the produced power of the inverter.