Two 410 Watt peak panels were not enough for me to utilize the 800 Watt inverter. Since the angle on the balcony is not ideal and also the inverter only handles 13A, I could rarely reach 600 watts in practice with two panels. After my panels provide a relatively low voltage, I am currently testing 2 panels in series on one input. With 4 panels, the balcony power plant is a bit oversized, but manages the 800 watts easily and also delivers in cloudy conditions neatly. Due to the fact that the voltage of the panels increases at lower temperatures, the setup could be problematic in winter. I will adjust the article if I have new findings here. The total cost is still under 1000 € even after the upgrade.