35 mph Electric Scooter Build - joshuarothfuss/projects GitHub Wiki

This is my favorite project so far. Originally I didn't want a scooter, but as I walked up to 20 minutes to and from class every day, the idea became more attractive. I am currently building Version 3. Below is the process of how the scooter was developed.

Link: Google Photos Album of Everything Scooter

Tools/Skills Used

  • Basic Hand Tools
  • MIG Welding
  • Breadboards
  • Fusion 360 -Design and Simulation (only for Version 3)
  • platformIO
  • Angle Iron
  • Band Saw
  • Drill Press w/ milling clamp
  • Drill/Impact Driver
  • Oxy-Acetylene Torch
  • Deburrer
  • VESC
  • ESP 32
  • SendCutSend

Version 0

I wanted a transportation device that would preserve kinetic energy. The picture "Huffy" Scooter is what was used. It was a great scooter, but it would take 10 minutes to get to class and I would be drenched in sweat upon arrival.

Version 1

This was to improve upon the previous version by adding a motor.

  • Hardware

    Due to my electrical background in RC cars and planes, I turned to what I knew first. I used a 8s 1275Kv motor and 200amp ESC, both made by Traxxas. Gearing was necessary to make this useful. 2 pillow-block bearings, a 10mm steel rod, rack and pinion, and 2 sprockets. I also used square aluminum tubing, 2 10 inch wheels. 3/16x1 inch steel bar, disc brake caliper, assortment of bolts, servo wire, 8-gauge wire, arduino nano, throttle lever, brake lever, and brake cable.

  • Construction I started by using some the steel to make trailing arms and front forks. All cuts were made with an angle grinder. The drive line was a little harder to make, and took a majority of the build time. Then it needed a battery box, which was added on the underside.

  • Results By the end a had an electric scooter that technically worked. It was loaded with issues, the biggest one was the gearing was loud, and a high failure point. The RC parts just couldn't handle real use. The flex in the plate that I mounted the motor and gears to also deformed to much and cause chain derailment, and gear striping.

Version 2

Version 2 is where there was some real success. It used the frame from last version, but upgraded all the electronics

  • Hardware

    All Traxxas hardware was removed, and a MAKERX GO-FOC HI100 vesc was using in combination with a Flipsky 7070 100Kv motor. Aluminum flashing was used to make sidewalls for the battery bay. The Arduino was also removed.

  • Construction

This was a 16s system so the wiring harness was converted from 8s2p to 16s1p. The previous mount plate for the drive assemble was removed. A new motor mount was made, the motor now had enough torque to attach the sprocket directly to the motor. The Vesc had an ADC directly on it, so the arduino wasn't necessary for converting to PPM or PWM. A charging port was also added, along with a 16s battery balancer to keep a Lipo cell from over-draining or exploding.

  • Results This version was amazing. It could sustain about 38mph, with a 21/80 sprocket ratio. See video link below. The biggest issue was charging, and waterproofing. I had to disassemble the scooter an annoying amount to charge it. Any day, there was even a heavy dew I couldn't use it. After a couple of months of use the quickly made parts started to ware and become unreliable. This is what led to version 3.

Version 3 Speed Run

Version 3

This version isn't finished. The entire scooter was made in Fusion 360 and then the relevant parts were ordered from SendCutSent. Everything is ready for assembly except the gooseneck.

  • Hardware
    1. 4x4-24 inch,1/8 thick, 6061 T6 aluminum for frame
    2. 2x2-12 inch, 1/4 think. 6061 T6 aluminum for neck
    3. 1/4 thick, 5052 aluminum for hinge and trailing arms
    4. 1/8 304 stainless steel for motor mount and sprocket adapter
    5. 3/4 inch stainless steel rod for hinge pin and lock
    6. Purchased front forks with suspension. There are a ton of accessories like a 3.0 PD hook-up to use as a battery bank. Also a gyroscope for wheely balancing. Panel mount usb-micro connectors for reprogramming without disassembly. LCD screen on handlebars for travel data.
  • Construction

Lots and lots of tapping and counter sinking. Also a fair bit of aluminum welding. See results.

  • Results

The biggest thing right now is the nearly complete Fusion 360 file. This also allowed for stress simulations. The one pictured shows the displacement under an 800lb load. Which is essentially it carrying me and a friend with luggage, going 30mph, over a speed bump. A number of other test were run but they aren't pictured.