A Mountain bike converted to an E-bike using a brushless DC outrunner motor.

Specification

• Power: 3550 W (motor theoretical)
• Top-speed: 25 km/h
• Weight: 20 kg
• Features:
  • Mechanical clutch: easily move the motor away for driving normally (without assist) with no losses
  • Regenerative braking
  • Anti slip regulation

Concept

Friction drive

The idea was to avoid making very significant changes to the bicycle and make a custom conversion kit.
The output shaft of the electric motor is pressed directly on to the rubber tire of the bicycle to transfer the power.

Problems

1. Low efficiency: With a friction drive there is a lot of power loss because the tire continuously gets squeezed by the motor shaft.
2. Lack of grip in wet condition: When the tire is wet there is alot of slip between the tire and motor shaft

Components

Mechanical parts

• Used Ghost Mountain bike 26’’
• 3d-printed holders

Motor

• Brand: Maytech
• Name: MTO6374-170-HA-C
• Type: Brushless DC outrunner
• Voltage: 11.1 - 50 V (2-12S)
• Current: max. 65 A
• Power: 3550 W
• Rotational speed: 170 rpm at 1 V (KV: 170)
• Output shaft: diameter: 8 mm keyway: 3 mm
• Weight: 0.83 kg
• Sensors: With hall sensors

Control

• Type: VESC bldc motor controller
• Name: MTVESC50A
• Current:
  • continuous: 50 A
  • max burst: 240 A
• Voltage: 9-50 V (3-12S Lipo)
• Input Device: Thumb throttle

Battery

• Type: Self-made Li-ion (without spot-welding)
• Cells: Samsung INR18650 25R 2500mAh 3,6V - 3,7V
• Voltage: 37V (32 - 42V)
• Capacity: 460 Wh (37 V 12,5 Ah)
• Cell connection: 10 series, 5 parallel (10s5p)

Videos

First drive

2018.09.03

Gallery