There is no one answer for this question because it depends on the model of electric car and how much you drive it.
A good estimate for electric usage for those on the high end – those who drive every day – would be between 500-600 kWh per month. It would take a properly-aimed 4kW solar system to produce this much energy.
Typical users should be able to get by with 300-500 kWh a month, and a 3kW solar install should be sufficient to produce this amount of energy.
These numbers are just estimates and will vary with car type and driving habits. Still, if you’re considering an electric vehicle and you’d like to charge it with 100% renewable solar power, this is a good gauge for how large a solar setup you would need to install.