I built a lithium ion powered bicycle to test out the technology. It has a 48 volt 10 AH LI-ion battery with a 2 KW external drive. The lower rated internal drive smoked within a few days.
I used a Magic Pie motor. The motor broke free of its torque arm and spun free on its shaft a number of times. This ripped the wires out of the motor and blew out the hall effect position sensing transistors. I spent many hours fixing this problem. I bought 3 hub motors before this was all done. They are less than $200. My most recent modification was to weld the shaft on the torque arm. That looks good so far. They are both hardened steel parts and the weld could snap. I told the welder to get it hot and put on a lot of metal. I was crossing the road with the bike going for a space in the traffic. I gave it the full throttle. It should have made it across with room to spare. The battery management system cut of the supply power and the bike bricked. I had to peddle it very hard against the load of the motor to get out of the way. The traffic did not slow down for me one bit. A truck was coming fast. The Battery Management System senses a low voltage on one of the cells and cuts of the power pack to save the battery. Of course that bricks the bike and risks me. I jumped out the shutoff transistor. I would watch when the battery manually and limit its use this way. There was no more bricking. One year later the battery is ruined. Four of the cells no longer hold any charge. Several others hold only a volt. They should hold 3.5 volts. The cells appear to be internally shorted out. It's $500 for a new battery. That's a bit steep and the bike may just sit in the shed forever. I would never want an electric car. I purchased anther toy in my older age; a MIDI Cooper convertible. I got it used for a good price. I am 6 ft 4 in and fit nicety in it. It has a gasoline engine that used very little gasoline and is doing just fine. ICE forever! Frank Z
