If you want to look at the limits of what physics seems to allow (cost practicality be damned), look at things like americansolarchallenge.org winners. They eve

If you want to look at the limits of what physics seems to allow (cost practicality be damned), look at things like americansolarchallenge.org winners. They even have a multi-occupant-vehicle class nowadays. The 2018 MOV winner (https://www.americansolarchallenge.org/the-competition/american-solar-challenge-2018/ https://www.americansolarchallenge.org/the-competition/ameri... ) logged 1762 miles over 58.4 hours, or about 30mph average pace (with a 16.8kWh battery, but no external charging, just the ability to time-shift some energy). That's with a vehicle that looks like this: https://www.youtube.com/watch?v=aE9gkYsR4TU https://www.youtube.com/watch?v=aE9gkYsR4TU