about the eCortina v2
eCortina Article in May issue of CurrentEVents Magazine
The eCortina v2 electric bicycle is a more refined and reliable machine than my first electric bike build, of two years ago. It features a substantially larger motor and larger battery pack. Also as the weight of the battery pack and all other associated electronics are located in the triangle, the weight distribution and handling are far superior in the current build version.
This custom motorized bicycle, and other electric vehicle projects under development, use high performance motors, batteries, and controllers from the Radio Controlled (RC) hobby business. These RC motors are lightweight brushless permanent magnet in-runners (magnets rotate inside fixed wire coils) and outrunners (magnets rotate outside fixed wire coils).
The hybrid electric bicycle system is designed so that one can pedal only (human power), motor only (electric power), or in hybrid mode both motor and pedal at the same time. Under hybrid running the distance one can ride under one charge is extended. However, realistically the eCortina must be considered a motor bike with human assist.
The batteries are Lithium Polymer (LiPo) basically a lithium ion chemistry variant. These batteries are sensitive to overcharging and over depletion, meaning that purpose built RC chargers and active, while in use, battery state monitoring, via a Cycle Analyst (not a BMS), are required to ensure good battery life.
I am currently monitoring bike performance and range and will post results as they come in. However, theoretically: 48v x 10Ah = 480Wh. LiPo batteries do not want to be discharged to less than 80% of total charge so: 480Wh x 0.8 = 384 Wh. If say the bike uses 25Wh per mile (to be determined but this is a conservative number): 384Wh / 25Wh per mile = 15.36 miles. The eCortina should go about 15 miles under mild riding with some pedaling. If I am able to add two more battery packs this number goes up to about 23 miles.
The drive systems are derived from mostly bicycle related parts and concepts. There are two BMX style freewheels to allow pedaling without driving the motor and motoring without forcing the pedals to rotate. The BMX chains employed here are strong and up to the task of propelling this bike reliably. A Shimano Nexus rear hub, a 3 speed transmission and standard bicycle part, allows the motor to run in its efficiency range.
More to come…