This is a solution in search
This is a solution in search of a problem. For daily-drives (commutes) most people will find it just extra dead weight.
For long road-trips, it's inability to quick-charge makes it next to useless except for people who only want to go about 150 miles per day!
What's needed is a towable or (temporary internal) genset using LP or gasoline for those rare long trips.
An alternative that would be lighter and more economical? A pusher-trailer, which would allow you to recharge using regenerative braking and would not contain a redundant generator of it's own!