It seems to be free if you come back and get the battery you dropped off - which seems to makes it possible to drive across the country with no more than 90-sec

It seems to be free if you come back and get the battery you dropped off - which seems to makes it possible to drive across the country with no more than 90-second battery stops, and drop them all back off taking the same route back. Don't know if they'll be okay with that, but it's an awesome possibility. That's thousands of miles with free (renewable) energy and fast.