Lloyd
My Electric Motorcycle
How it beganMy sophomore year in high school, I decided that I wanted to make my own personal electric vehicle. Most of my transportation needs consisted of short trips within a five-mile radius of my residence, and it felt like a waste of money and energy to drive a car. While owning a car gave me a freedom an electric vehicle unfortunately could not completely provide, I wanted to create a mode of transportation that was light, quick, efficient, and practical for driving through the hilly roads of my hometown. Thus was born my mission to make an electric motorcycle.
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The First Step: My Motorized BMX BikeMy first ride-able electric vehicle was built off of the chassis of a children’s BMX bike my friend was throwing away. The bike was powered by a NPC-T64 Motor running at 24V provided by two NPC-B1412 SVR AGM Batteries. The motor was preassembled with a 20:1 gearbox, allowing for a near 1:1 gear ratio going from the gearbox to the rear wheel. The speed of the motor was controlled by an off-brand speed controller which was rated to supply up to 200A at 24-36V. I mounted a voltmeter and an ammeter to a piece of scrap Lexan to act as a rough battery gauge. The only part of the bike I did not completely construct myself was the final motor mount; my first version could not handle the torque of the motor, so my father welded a thick steel tube support to my bent motor mount. As a final touch, I made own seat out of an old pillow for a more comfy ride.
The bike rode great, moved completely silently, and blew every electric scooter I had ever ridden out of the water. However, it was still a toy. I could zoom around the neighborhood, but I could not ride it outside my neighborhood reliably. |
From Electric Bike to Electric MotorcyleSince the bicycle form factor proved to be too small for my needs, the next logical step was to build off of a motorcycle chassis. I was able to purchase a 1980 Honda Twinstar with a seized engine for $50. The bike was not in great shape, but provided a perfect base to build off of.
The new bike was powered by three NPC-B1812 Batteries, the NPC Black Max Motor, and the same speed controller from the BMX bicycle. My general design consisted of two nearly symmetrical 1/8in aluminum sheets sandwiching the frame of the bike with cut outs to hold the batteries, motor, and jackshaft. The jackshaft was necessary to achieve a gear ratio high enough to reduce the motor’s 3800RPM to a reasonable speed of 20MPH. I used a freewheel pulley on the motor to reduce the drag of the motor when coasting; in retrospect, this was unnecessary. With a max speed of roughly 20MPH and enough range to make it from my house to my high school, this could be called a real vehicle. However, it was barely a vehicle. While I could make it down to my high school, it barely had enough power to climb the hill back home, even if I fully charged it at school. More importantly, I was cooking the motor. I attempted to make a radiator by wrapping the motor with copper tubing and pumping water around the motor and through a coil of tubing on the front of the bike. While this did remove some heat, it was not enough to address the fact I using too small a motor for the weight and speed I wanted to have. |
Making a Real VehicleIt was time to make Lloyd a real electric motorcycle. Having recently taught myself how to MIG weld using my friend’s welder, the flimsy aluminum side panels were removed and in their place I welded a 1/2in thick steel plate motor mount. I had noticed previously that aluminum panels would flex when the motor was under heavy load, allowing the chain to skip; with the new motor mount, I wanted thereto be no flex whatsoever. This was even more important since I had moved away from the NPC Motor to the Etek-R Motor with more than triple the power.
The battery mount was born half out of necessity and half out of choice. With now six batteries, compared to the three I had previously fit snugly into the shape of the frame, it seemed likely that I would have to mount them in two separate rows. The “V” shape reminded me of an engine and added a bit of style to bike. Once all the welding had cooled, I took the bike out for a spin. It felt like a real motorcycle, with the added bonus of being completely silent. While the bike was ride-able, it took another month to make it more or less “complete”. This included adding mirrors, signals, locking mechanism, ammeter, etc. I say “complete” in quotations for I will never see this bike as a finished project; I will continue to work to make it better as long as I have it. |
Round 2, With More LithiumIn Progress
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