Depends on how much assistance you actually get/use... I know that on my set up on a 40Km ride if I am on level 1 all the time, about 14Km/35% of the ride the motor was doing basically all the work... I would have used 2 bars out of 8 of battery power. If I used level 4 for the whole ride I would have about 1 bar left out of 8 after 40Km about 30Km/75% of the ride the motor was basically doing all the work... Using throttle only, I wouldn't even make 40Km, about 30Km would be the limit with the motor doing all the work...