I was thinking of a 200 mile range for an RV or long range bus . However , I don't know how much energy the battery would need . I wonder if 500 kWh would be enough for 200 miles ? A big rig could haul giant batteries underneath the bed of the trailer it hauls and use a range extender to improve fuel economy . I'm no engineer , but I believe a range extender generator converting electricity would probably improve fuel economy by 20- 40 %
Let's say the tractor rig had a 50 mile range battery and a range extender , and the trailer another 200 mile battery .