Chemistry determines the cell voltage (1.2V or 1.5V and there are others like Lithium at 3.0V), whether the battery is rechargeable, and how the voltage changes as the battery discharges i.e. at what voltage is the battery considered to be flat or fully charged. Switched mode power supplies. One more point.
The Average Bike Riding Speed. The average road bike speed is between 11 and 12 mph. Bike riding speeds vary widely depending on your riding conditions. When you are zooming down a paved hill, your speed may increase to over 20 mph, while you may slow to only a few miles per hour when you are climbing a steep or rocky grade.
I am now a lot fitter, have a road bike and cycle a lot further without feeling shattered at the end of it. I now average 15mph on a short ride (up to 15-20 miles) and between 12-14mph for longer rides (over 35 miles). I reckon I do 10 miles in about 40 mins. I can do 15 in an hour or just under.