Electric Bike


last updated: June 22, 2021


Design goals

  • Cheap
  • Minimal bike modifications – it should only take minutes to put the bike back in it’s original condition
  • Light – it shouldn’t be that hard to carry


The display



The display shows the following information

  • Speed (km/hr.)
  • Time of day
  • Distance remaining under current conditions (km)
    Valid only when speed, power and peddling effort is steady
  • Power consumption (Watts)
  • Odometer (km)
  • State of charge based on coulombs used (%)
  • State of charge based on voltage (%)
  • Amp-hours used so far

There are a variety of other values available to be displayed, but they’re not that important and there’s only so much room on the LCD.

Here’s the source code (June, 2021)


The parts

  • Arduino Nano clone
  • Current sensor (Allegro ACS756).
  • 5V switching power supply
  • Hall effect sensor
  • real time clock


24V, 1200 RPM, DC, brushed, 4″D, 6″L, very heavy. I’d like to get a better one.


Motor controller

From Ridemore


The sprockets

There is a 9 tooth sprocket on the motor and 33 on the wheel.



3 10 amp-hour Lithium Iron Sulfide batteries from . They are 4 cell. Total voltage ranges from 42V to 30V.



The cost

  • batteries: $270 for 3
  • motor control: $150
  • upper sprocket: $20 including shipping and other costs
  • lower sprocket: $40
  • chain: $12

The rest of the parts I had lying around

 Posted by at 4:38 AM