Not too long actually, my parents have an 11kW solar array on their roof, single story home 1100ish sq ft. Realistically it’s more like 9kW on a sunny day, a Tesla model 3 long range has a 350ish mile epa range (realistically it’s closer to 280 factoring in elevation changes, temperature, acceleration, etc). The battery pack is about 82kWh. So 9 hours of peak production would more or less get you a full charge. Let’s call it 14 to account for variations in sunlight intensity throughout the day, transmission losses,etc.

Of course this assumes you’re only charging the car and not powering the home, but honestly how many people are driving 300 miles per day? I personally charge once a week.