I've noticed that my quattro lowers voltage of the system, without apparent reason.
Case - Grid with 5kw connected to AC IN 1. Fronius + house loads connected on AC OUT 1 (ESS config). For some reason, i can't get the batteries to charge with excess, as they should, so I manually switch "keep batteries charged" in the evening. Even if I have 1kwh charge on the batteries, the grid voltage drops to ~180-185v and during evening my fronius disconnects.
If I add 2-3 kwh loads, but not trough the quattro, the voltage only drops to 195v (from 205-210v).