I have a 3 phase ESS setup with 3 x 5000 VA Multiplus 2, 1 MPPT, 1 Fronius ongrid inverter and a Pylontech battery bank of 20 kWh.
If one of the phases fails then the ESS system switches over to inverting mode feeding the whole house from battery. Even though the other 2 phases are present the ESS will ignore them and run the battery down to SoC then blackout the house.
From my research this is a common problem where 1 phase goes out of specs and has not been solved by Victron (found posts from 2022 describing this issue)
My ideea is to add an Automatic phase selector device that I have already purchased in the past (https://www.novatek-electro.org/pef-301/). This device gets a 3 phase input L1 L2 L3, monitors the phases and outputs 1 phase 230V, the most reliable one.
From this phase I plan to feed an aditional Multiplus 2 3000VA that will only feed the 48V bus bar to charge the battery bank.
Plese see bellow arrangement where the red lines represent the newly addition to the system.
Any toughts on this solution ? Could it be integrated in ESS to be last priority to charge batteries ?
Automatic phase selector