Electric bike project
last updated: August 1, 2014
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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.)
- Distance remaining under current conditions (km)
Valid only when speed, power and peddling effort is steady - Power comsumption (Watts)
- Odometer (km)
- State of charge based on coulombs used (%)
- State of charge based on voltage (%)
- Amp-hours used so far
Here's the source code (Aug. 1, 2014)
The parts
- Microcontroller (PIC 18F2620)
- Current sensor (Allegro ACS756).
- 5V switching power supply
- Hall effect sensor
motor
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24V, 1200 RPM, DC, brushed, 4"D, 6"L, very heavy. I'd like to get a better one.
Motor controller
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From Ridemore
The sprockets
There is a 9 tooth sprocket on the motor and 32 on the wheel.batteries
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3 5 amp-hour Lithium polymer packs from Hobby King in China. They are 3 cell, 20C. Total voltage ranges from 37.8V to 27V.
The cost
- batteries: $300 for 2 sets, includes $100 for shipping
- motor control: $150
- sprocket: $20 including shipping and other costs
- chain: $12