ABB Aurora WIM power supply

Hello Renzo, a great project you have made. I think it's really great and would like to rebuild it. What I wonder, why do you need a battery? You wrote, if there is no sun, the ESP runs via battery. Where does the ESP get the power from when the sun is shining? You must have a 230V to 5V power supply somewhere. At the 230V you actually always have power, unless there would be a power failure. Can you give me a hint or post a photo? Thanks Chris