For a 20 mile range with a 600 Watt motor running at moderate speeds a battery pack made from three 12 Volt 35Ah will do the job. If there are many hills, or the cycle would be used at or near full throttle for the entire 20 miles, then a battery pack consisting of three 12 Volt 50Ah batteries would be a better choice.
Please let us know if you have any questions.
Same questions apply:
Thanks in advance for your recommendations!
Kyoto Cruiser from back Kyoto Cruiser from side