- Blog entry posted in 'Uncategorised', July 31, 2011.
The heart of this project is the motor that drives the bicycle. Due to all the weight it would have to move, I needed a powerful 12 volt motor capable of producing a lot of torque. My first idea was to use a motor from a treadmill, but that hope quickly faded away--treadmill motors generally use 130 volt DC motors, which was too much for me. From there I started thinking more about motors that can be found in cars. I figured that they are generally in high-torque applications and ran on 12 volts--ideal for this project. Unfortunately, most of the motors I found were fairly small and would not work to power a bicycle. However, then I started looking at the engine. The first thing that caught my eye was a relatively large motor with the shaft going inside part of the engine.
I guess I should mention right now that I do not know very much about cars. I didn't know much about this particular motor, but I figured this was the starter motor. It turned out I was correct. This motor seemed to fit my needs. It ran on 12 volts and was capable of producing a large amount of torque. So, before doing anything else, I decided to do a bit of research....
Hong Bin, August 23, 2011
12 Volts, what is the current? current is a important thing to power a bicycle. and aslo you should think the size of the motor, large motor is not good for placement.
DerStrom8, August 23, 2011
Hello Hong Bin. Good to hear from you :) After doing some research, I learned that on average, a starter motor draws about 50 Amps. Of course, this value changes depending on grade of the road, weight on the bike, and countless other variables. Figuring 50 Amps, Two 12v 9Ah motorcycle batteries (average capacity) would last for about 21 minutes before they're completely drained. As for the placement, you're right. Putting the motor in the wrong place could cause the bike to be very unstable and easy to tip over. Generally a low center of gravity is the best idea, and of course, make sure it is well-supported. Thanks for the comment :)