Battery charged and range

Battery has been fully charged. It took 6 hours for the charging process to be completed for a fully depleted battery. I have since ridden and charged the battery 3 times, however, did not ride down to the battery's red light but to about 1/3 charge left. Range has improved since the first ride a week ago, from 50km actual to estimated 65km. Speeds range from 50km/h to 80km/h, mostly at 70km/h, (70%).