Electric Bicycle
This project started because MSOE would not offer a parking permit in their lots for full time employees. Because I was a graduate student I could not purchase a parking permit like all the other employees.
Regardless, my commute is about two miles and taking a car seemed kind of unnecessary. But I didn't want to spend an hour of my day walking back and forth to work. Peddling a bicycle in winter is difficult. A few students have mopeds but I didn't see that as an option because it's a second job for them to maintain those 30 year old engines.
The answer was to modify a mountain bike frame to use a 1 hp electric motor and 2 group U1 gel cell batteries.
The bike and modifications were modeled in Solidworks. Pieces were cut in the machine shop and welded onto the frame. The electric motor was left over from a senior design project and had some serious issues. My best guess was that the armature was swapped from another motor because only half of the brush made contact with the commutator. So the commutator was trued, the housing machined down and re-assembled correctly.
I also replaced the front forks for ones that would accept a disk brake caliper. The industry standard for disk brakes is for 24" tires while I use 20" tires. This meant that custom brackets needed to be made to fit the disc rotor.
Once all of the mechanical changes were made to the bike, it was disassembled and taken from my lab to my parents' garage for Christmas break. There I was able to sand-blast and paint the frame and swing arms.
The batteries and speed controller were mounted on the frame as well as a headlight and tail light. Once everything was wired, it was obvious that something was needed to cover the batteries and wires for safety, aesthetics and theft deterrence. So before the frame was painted, I had installed foam on the frame and cut away a 'gas tank' looking shroud.
After several layers of bondo and much sanding the cover was painted and installed with an on/off and light switch.
People have the same three questions when I get stopped on the street: "how fast does it go" "how far does it go" and "is that electric."
I never put a speedometer on it but I can say it goes fast enough to keep up with traffic. I can make it to work and back on a charge but I installed a permanent battery charger on the bike so I charge it wherever there is an outlet. Finally, yes it is electric. The technology is old; lead acid batteries have been around for a while as well as DC brushed motors. But it was an inexpensive solution; it is fun to ride and it solved my parking problem. I drive it all year round and find it easier and more comfortable to ride even on the coldest winter days.
