Directly from the sun during the day
When the car is at home during generation, energy can flow directly from the photovoltaics to the vehicle. There is no need to store it in the home battery first just so the battery is used.
If you only come home in the evening, the home battery can shift part of the daytime generation to later. However, it does not have to cover the car's full charge.
What matters is the energy for the next journey.
You usually do not refill the vehicle's full capacity every evening. For the design, we need the daily mileage, consumption, arrival time and next departure.
If you arrive at 18:00 and leave at 07:00, you have 13 hours for charging. This can create room to spread the load.
The home and the car do not have to compete for power.
Cooking, water heating and a heat pump can increase the household's demand in the evening. Smart charging control can temporarily reduce the vehicle's charging power, within the system's capabilities, and increase it again later.
A charging station does not have to run at maximum power all the time. Its control can take into account PV generation, the home's consumption, the available power and the departure time.
Do you need a bigger battery because of the car?
Not automatically. Energy can come directly from the sun, from the grid or from the home battery. Your routine and the benefit of each option are what matter.
With a second electric vehicle, we reassess simultaneous charging and the capacity of the home's grid connection. Higher consumption does not mean that everything has to be solved with a bigger battery.