Factors to be considered while selection and sizing of a hub motor for electric bike.

The size of the hub motor and battery suitable for a CG 125 motorcycle conversion to electric power depends on several factors, including your specific performance requirements, budget, and intended use. Here are some general guidelines to help you determine what might be suitable:

1.      Motor Size.

·         Power Rating: A typical CG 125 motorcycle engine has a power output of around 8-11 horsepower (HP). To maintain similar performance, you'd want an electric motor with a power rating in this range or slightly higher to compensate for any losses in the conversion process.

·         Voltage: The voltage of the motor should be compatible with the voltage of your battery pack. Common voltages for electric motorcycles range from 48V to 96V or more, depending on the desired performance.

·         Type: Hub motors are a common choice for electric motorcycle conversions due to their simplicity and ease of installation. You can choose a single hub motor for the rear wheel or a dual-motor setup for increased power and traction.

3.      Battery Size:

·         Capacity (Ah): The battery capacity determines how far you can ride on a single charge. A larger capacity will provide more range. Consider a battery capacity that matches your daily commuting needs or desired range.

·         Voltage: Ensure that the battery voltage is compatible with the motor's voltage. For example, if you choose a 72V motor, you should use a 72V battery pack.

·         Chemistry: Lithium-ion batteries are the most common choice due to their energy density and longevity. They are available in various chemistries, such as LiFePO4 and Li-ion NMC, with different trade-offs between energy density, weight, and cost.

·         Configuration: Battery packs can be configured in series (increasing voltage) or parallel (increasing capacity). The configuration will depend on your voltage and capacity requirements.

4.      Controller:

·         Choose an appropriate motor controller that matches the motor and battery specifications. The controller controls the motor's speed and power output.

5.      Charging Infrastructure:

·         Consider the charging infrastructure available to you. Make sure you have access to chargers compatible with your battery pack's voltage and charging speed.

6.      Weight Distribution:

·         Keep in mind that electric components (motor and battery) are usually heavier than a traditional internal combustion engine. Ensure that the weight distribution is balanced to maintain good handling and stability.

7.      Regulations and Licensing:

·         Be aware of local regulations regarding electric motorcycle conversions. Some regions may have specific requirements or limitations on power and speed for electric motorcycles.

8.      Budget:

·         Your budget will play a significant role in determining the components you can afford. Quality components can be expensive, so plan accordingly.

It's essential to do thorough research, possibly consult with experts or electric motorcycle conversion specialists, and consider your specific needs and preferences when selecting the motor and battery size for your CG 125 electric conversion project. Additionally, ensure that safety measures, such as proper cooling and thermal management for the motor and battery, are in place to avoid overheating and ensure longevity.