Button with % slider and Timecontrol

Hello, everyone,
I’m new here.
I’ve had Home Assistant for 3 days and I’m having a hard time right now.
I would like to create a button where I set a slider to a % number, which turns on a shelly for a period of time.
The whole thing is intended for my wallbox, if I connect my car and say the battery level is 60%, the wallbox should stay on for 2:30 and thus charge the car.
I have prepared the calculation for the loading time and could store it as a fixed value for the button.
Maybe someone can help me.
Thank you very much for your time.
Regards

Hello,

no one here who can help me?
I would like an input_number where the values ​​are manipulated.
Min is 0% and max is 80%. These should be converted to a minimum of 36 KW and a maximum of 0 KW.

Is this possible?

Best regards