https://www.evspecifications.com/en/news/daea4e

Best source I could find. Seems like a low of 5-6 km in winter, a max of 34 km in summer, average 22-24 km (probably 10 in winter, 25 fall/spring, 30 summer).

But again it’s all speculation. Toyota is using much fancier panels, 34% actually, and says up to 34 miles a day: https://electrek.co/2019/07/05/toyota-solar-electric-car/

Again it really comes down to whether they can cut installation costs in a mass market product. Solar modules (the 18-20% variety) themselves are absurdly cheap these days so if it can be mass produced it’s sort of “why not?”.

Granted I doubt these are the people to do that, but I could see a major automaker pulling something like that off in the next 15 years or so.