Nullmodem

Hi guys, I also have the problem of no charging on cloudy days (my inverter has got firmware version 45.07). I haven't connected utility power, so can't tell about the unwanted feed. My observation is that in cloudy conditions, the PV voltage is stuck to around 70-100V, pretty much independent of how many panels are connected in series. I have two strings with a nominal max power voltage of 200V. No matter if I connect only one string, or both in series, or parallel, the MPPT of the inverter does not seem to find the correct voltage under cloudy conditions. There is no shadow on my roof, and I can compare to another two strings on the same roof that I connected to a simple PWM regulator using a fixed voltage. While the PWM regulator achieves about 100-150W at 200V, the inverter shows mostly around 10-20W at 80V (Not sure how accurate these values from the display or from the app are, but I'd trust the voltage more than the power reading). Only when the sun comes through and the power exceeds about 150W, the inverter increases the solar voltage also to around 200V. I did not yet dare to flash a different firmware version, but if I understand Jopie right, it wouldn't improve the situation. Do you think I should try nevertheless? /nullmodem