What's in a electric bike conversion kit? How to upgrade motor or battery?

• 1x Motor
• 1x Intelligent Motor Controller
• 1x Controller Box
• 1x Pedal Assist Crank Sensor
• 1x Pair of E-Brake Levers
• 1x Twist Throttle
• 1x LCD Display
• 1x Cable Ties Set
• 1x Freewheel
• 1x Battery & Charger Set

Sometimes battery is not included when you buy from overseas seller. Motor, Controller, Display and Battery are most important four parts in it. 

If you would like to upgrade the motor of your ebike, you at least need to purchase a new motor that is compatible with your existing ebike system. You will also need to ensure that the new motor has the same or similar power rating as the original motor, as using a motor with a significantly higher power output could cause damage to your bike's electronics, battery, or other components. 

Using a 36V battery with a 48V motor may result in the motor not receiving enough power to function properly, while using a 48V battery with a 36V motor may overload and damage the motor. It's important to match the voltage of the battery and motor to ensure safe and efficient operation. 

Additionally, you may need to replace or modify other components of your ebike system, such as the controller, battery, display or wiring, to ensure they are compatible with the new motor.

Moreover, using a low-capacity battery with a high-power motor can lead to a shorter battery lifespan. This is because the battery may struggle to keep up with the demands of the motor, causing it to degrade faster over time. It's important to choose a battery with a capacity and discharge rate that matches the requirements of the motor to ensure both components can perform optimally and have a longer lifespan.

It is recommended that you consult with an experienced ebike technician or manufacturer before attempting to upgrade your ebike motor to ensure you are making safe and effective modifications to your bike.