Partly OFF topic - BMS --> solar charger

Hi to all.
I am planning to build one 12KW OFFfrid solar system for one of my friends. ON grid can be used but only if really needed, and it can be set on different power lines. The idea is to charge EV with DC directly form panel, and when this is done, DC switch should be used to switch battery power for use on hybrid 6KW inverter. Of course, it's not as simple as it seams but lets try to separate this into few main parts.
--> EV charging time --> 6 hours --> every few days.
--> constant working house devices ( fridge etc ) --> 24h --> 1KW
--> partial working devices, cca 2H per day --> 2,5KW
I would like to define battery bank, one arduino based BMS and if possible, automatic DC switch which will detect that the car is charged and switch charging to battery bank. In other words, when car battery is charged, arduino based system should activate DC switch and pass the solar panel charging directly to battery bank.
I guess you all are wandering why am trying to charge EV with DC and why use DC charging station. The answer would be: i can expand solar panel installation up to 12KW ( i have that much room on the roof ) but as far as i know there is no real 8KW or higher inverter on the market and if there is, it must be quite expensive...
Other thing is , DC chargers are faster... Of course , they are also more expansive.
Anyhow, what do you think regarding power bank and automatic DC switching ?
Best regards !