Get familiar with parameter used.

Gross Weight of Vehicle (Kg): It is total weight of vehicle including driver and maximum number of passenger.

Desired (Rated) Speed of Vehicle (Km/h): It is desired maximum speed of vehicle at rated load. It is also called rated speed.

Time Required to Reach Desired Speed (Sec): It is time required by the vehicle to reach rated speed from zero initial speed. It defines important performance parameter of the vehicle as starting torque requirement or say vehicle pick-up.

Motor Power (W): It is rated output power of the electric motor defined by the manufacturer. Note that it is mechanical output power represented in electrical unit of power watt.

Motor Rated Voltage (V): It is voltage for which motor is designed to be operated. It is specify by the manufacturer. 

Motor Rated Current (A): It is current drawn by the motor in ampere at rated load and rated speed. It is specified by the motor manufacturer directly or indirectly by providing efficiency.

Motor Speed (RPM): It is maximum possible speed of the electric motor shaft at rated load. It also called rated speed of the motor. Generally it is mentioned in unit RPM –revolution per minute by manufacturer of the motor.

Motor Torque (N-m): It is amount of torque available at shaft of the motor at rated current and rated load.

Wheel Size (inch): It is diameter of vehicle wheel that produce torque by the direct or geared electric motor drive. Generally this wheel size is specified in inch by most manufacturers.

Gear Ratio: Gear is required to control torque and speed of the vehicle for available power. We can select higher torque with lesser maximum speed or higher maximum speed with lesser torque for available motor power. Gear ratio is ratio of teeth on motor sprocket (gear attached to motor) to the number of teeth on freewheel (gear attached to wheel). Or it is ratio of diameter in case of belt and pulley drive.

Battery Voltage Rating (V): It is rated voltage of battery specified by the manufacturer. Considering battery voltage same as motor operating voltage, it also called motor rated voltage.

Battery Ah Capacity (Ah): It is ampere-hour rating of battery specify by the manufacturer. It defines the storage capacity of electrical energy. Higher the Ah rating means higher the stored energy considering same voltage rating.

Electricity Charge (INR/Unit or USD/Unit): Electricity charge is per unit electricity cost which depends upon electricity providers of your state. One unit represents 1000Wh or say 1KWh energy. It is how we pay the electricity bill for our energy usage.

Electricity Cost of Vehicle (INR/Charge or USD/Charge): It is an amount to charge battery onetime fully, from fully discharged state.

Battery Range (Km/charge): It is total distance travel by the vehicle with fully charged battery until it completely drains. It also called vehicle range.

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Average Motor Power Calculation

Very first step for any EV project is to finalized motor power for required performance and parameter. For example find the required motor power for 120Kg E-bicycle to reach max speed of 25kg from rest in 7 second.


Gear Ratio

After selecting Motor, it is required to select the gear ratio to achieve desired vehicle speed and torque based on wheel size and RPM specified by the motor manufacturer.


Battery Range Calculation

How long vehicle can travel, is the first most interest of electric vehicle user. It depends upon battery Ah capacity, current drawn by the motor and rated speed of vehicle.


Rated Speed Calculation

All motor comes with rated RPM shaft speed. After using proper gear and using wheel size, vehicle rated speed can be calculated.


Torque Calculation

Motor torque is not provided, it can be calculated from rated motor speed and power.


Motor Efficiency Calculator

Motor efficiency can be estimated from power rating and rated current of the motor.


Rated Current Calculator

Rated current can be estimated when efficiency is specified by the manufacturer.


Electricity Cost of Vehicle

Cost of electricity for charging battery each time is an another important parameter of user interest. It can be estimated from battery Ah capacity and electricity cost per unit.


Running Cost

Running cost is also important parameter of user interest. However, running cost of electric two wheeler is very low as compared to battery replacement cost.


Battery Replacement Cost

Battery replacement cost is the important parameter needs to consider for the total cost estimation. It also helps comparing Li-ion battery over lead acid battery of same capacity for cost optimization.