800 W is que conservative for a schucko plug, which is typically rated for 13 or 16 A (>3000 W). I regularly charge the car at 10 amps (2400 W) on a schucko.
Super interesting! With such a big solar system, the self-consumption is already quite high. With a smaller solar system, the ROI for a battery would probably be higher. So in itself a big solar system is a nice alternative to batteries. Curious about the details of the 30kWP solar setup!
Nice write up! The new version Marstek Venus E 3.0 now natively supports modbus TCP via the normal network connection if you upgrade the firmware. So with that one you can skip the Waveshare setup.