With our frequent grid loss issues in my country it has brought back to light the problem I had with an AC Coupled SMA inverter on the Multiplus 1 5kVA. I was hoping that when I updated the firmware to 497 ( from 433 ) it would solve this however it did not. System is ESS configured - Multiplus with 3 kVA SMA at output ( AC coupled ) . The 3 kVA SMA has an very early modbus version which is not interpreted by the Venus so a Victron energy meter is configured to determine its energy output. Battery is 600AH lithium using BMS 2 wire assistant where Aux 1 is set to Float when BMS decides its had enough . When grid is lost and output by SMA is moderate ~ >1 kVA then the Multiplus immediately reverts to disconnect frequency and remains locked at this frequency seemingly permanently . Even when grid is restored ( > 10 mins ) it will not connect to grid. When SMA output is lowish ~ < 1 KW then this does not usually happen ( can do for ~ 20% of the time ) and the Multi successfully manages the SMA output via freq control.
I decided to to something different and removed the 2 wire assistant in the multi and selected "other type BMS " and this solved the problem . Frequency of Multiplus goes up during the power off transient but no high enough to trigger the disconnect frequency. Cause of issue found ! Now if only we can get the Venus to have a settable max SOC charge limit
