48V External Drive Motor for Mountain Bikes: Electric Assist Conversion Kit. Motor model: high-speed brushless motor 350W 48V. Main body size: 73 (length) 68 (width) 80 (height) (mm). Motor size: 7055 (mm). Speed: 30–35 km/h (pure electric). 40- 45 km/h (assist mode). 7.8AH (standard battery) parameters. Battery capacity: 7.8AH (18650 high-capacity sports battery). Battery voltage:: 48V (minimum: 40V–maximum: 54.6V). Range: 40-45 kilometers (pure electric). 55-60 kilometers (assist mode). Number of charging and discharging: 600 times. Battery size: 210 (length) 70 (width) 80 (height) mm. Charging time: 3-4 hours. 5.2AH (standard battery) parameters. Battery capacity: 5.2AH (18650 high-capacity sports battery). Battery voltage: 48V (minimum: 40V–maximum: 54.6V). Range: 25-30 kilometers (pure electric). 35-40 kilometers (assist mode). Battery size: 140 (length) 70 (width) 80 (height) mm. Charging time: 2-3 hours.