The quattro day or night, will every minute sometimes twice or three times, raise frequency up to 53hz, for a second or so, then drop to 50hz. However this stops the AC coupled PV inverter connecting to the quattro. This happens day or night and with the battery at any level even as low as 50 SOC. Have the latest Firmware for the quattro installed. I am running PV inverter assistant. Works perfectly when I have grid on ac 2 connected as the frequency stays at 50 hz. any solutions or work arounds. PV inverter assistant is set to start decreasing power at 50.2 through to 51.7 and disconnect at 52hz.