I find this difficult to believe. Filling up a low-end Model S requires 60kWh. Assuming you use one "tank" of charge per day (210 miles) and you have 5 hours of sun per day, this is 12kW of panels. Nowadays you can get around 200 watts from a square meter of panels (modulo proper cosine=1 mounting) so this is 60 square meters. Multiply by 1.2 for efficiency losses and it's 72 square meters. Granted that's a lot more than most solar houses need, but it also assumes you're driving 210 miles per day, which is more than most people.

Why do you need an acre to mount 72 square meters? Even if you're in the Arctic Circle, you don't need that much. And you won't be charging in the winter anyway :-)