Just some back-of-the-napkin math. An electric car uses approx .25 kWh per mile. Household solar gives you 15 watts/sq ft. Assuming a car 5 ft wide, the hood 5 ft long, roof 4 ft, and trunk 3 ft, that's 60 sqft of sky-facing surface. Accounting for rounded edges, let's make that 50 sqft. So 750 watts, or .75 kWh per hour.
That comes out to 3 miles of driving for every 1 hour charge. So your car sitting at work for 8 hours will give you 24 miles of power to drive home.
Adjust up or down based on location, summer vs winter, cloud cover, solar cell efficiency, etc.
Now what you can do is have your garage roof covered in solar, charge a stationary battery, then transfer from there to your car every night. Or swap-able car batteries.
Another possibility is have a design that keeps the solar on the car following the curves of the vehicle when driving, then have a parking mode that would extend / unfold solar to cover more of the car when it is parked. That would be good for people who live in apartments without charging ports, although if parking is provided for tenants then adding charging ports (for a fee) may be a thing.
And, importantly (which you imply, but I feel needs stating outright), this car-roof solar does not have to be the sole source of charging. It can be a convenient (and energy-efficient) supplement to whatever other charging options we can make work.
That comes out to 3 miles of driving for every 1 hour charge. So your car sitting at work for 8 hours will give you 24 miles of power to drive home.
Adjust up or down based on location, summer vs winter, cloud cover, solar cell efficiency, etc.
Now what you can do is have your garage roof covered in solar, charge a stationary battery, then transfer from there to your car every night. Or swap-able car batteries.
Another possibility is have a design that keeps the solar on the car following the curves of the vehicle when driving, then have a parking mode that would extend / unfold solar to cover more of the car when it is parked. That would be good for people who live in apartments without charging ports, although if parking is provided for tenants then adding charging ports (for a fee) may be a thing.