How to Select the Right Electric Motor for an EV

Choosing an electric motor for an electric vehicle is not simply a matter of selecting the motor with the highest power rating.

The right motor depends on the vehicle weight, required acceleration, top speed, tyre size, gearing, battery voltage, duty cycle, cooling system and terrain. A motor that performs exceptionally well in one vehicle may be completely unsuitable for another.

For EV developers, motorsport teams, startups and industrial vehicle manufacturers, understanding these parameters before purchasing a motor can prevent costly redesigns and performance issues.

At Agni Engineering Solutions, we help engineering teams identify and source motors and related powertrain components according to their application requirements.

1. Start With the Vehicle Requirement

Before selecting a motor, define what the vehicle needs to do.

Some of the most important parameters are:

• Vehicle kerb weight
• Maximum loaded weight
• Desired top speed
• Required acceleration
• Maximum gradient/gradeability
• Wheel and tyre diameter
• Number of driven wheels
• Transmission or reduction ratio
• Expected operating temperature
• Continuous operating duration
• Battery voltage
• Intended application

For example, a lightweight electric two-wheeler and a loaded electric cargo vehicle may both operate on a 72 V system, but their motor requirements can be completely different.

The motor should therefore be selected around the vehicle—not the other way around.

2. Understand Motor Power vs Torque

Two of the most commonly misunderstood specifications are power and torque.

Torque

Torque determines the rotational force produced by the motor.

Higher torque is particularly important for:

• Starting from standstill
• Climbing gradients
• Carrying heavy loads
• Off-road driving
• Towing
• Low-speed operation

Power

Power determines how quickly the motor can perform work and becomes particularly important as vehicle speed increases.

In simple terms:

Torque helps you get moving. Power helps you keep accelerating at higher speed.

A good EV powertrain needs an appropriate balance between the two.

3. Don't Look Only at Peak Power

Motor manufacturers commonly specify both:

Peak Power

The maximum power the motor can produce for a limited period.

Continuous Power

The power the motor can sustain during prolonged operation without exceeding its thermal limits.

This distinction is extremely important.

For example, a motor advertised as 15 kW peak doesn't necessarily mean that it can continuously deliver 15 kW.

For applications such as:

• Delivery vehicles
• Industrial equipment
• Cargo vehicles
• Off-road vehicles
• Long-distance EVs

continuous performance and thermal capability can be more important than headline peak power.

4. Consider Torque at the Wheels

The motor doesn't directly determine the torque available at the tyre.

The drivetrain also matters.

A simplified relationship is:

Wheel Torque ≈ Motor Torque × Gear Reduction × Drivetrain Efficiency

This means a relatively compact motor can produce substantial wheel torque when paired with the appropriate reduction ratio.

However, increasing the reduction ratio also affects wheel speed and vehicle top speed.

Therefore, motor selection should happen alongside gear ratio and vehicle-speed calculations.

5. Check the Battery Voltage

The motor and controller must be compatible with the vehicle's battery architecture.

Common EV system voltages include:

• 48 V
• 60 V
• 72 V
• Higher-voltage automotive systems

For example, Torus Motion's V2 motor series is available in 48 V, 60 V and 72 V configurations, with air-cooled and liquid-cooled variants depending on the model. The V2 range is intended for applications including L5 vehicles, industrial equipment, forklifts and tow tugs.

The battery, motor controller and motor therefore need to be considered as one system.

6. Motor + Controller Compatibility

Buying a motor without considering its controller can create problems during integration.

The controller needs to be compatible with parameters such as:

• Motor type
• Voltage
• Current
• Rotor position sensing
• Encoder/Hall feedback
• Communication protocol
• Peak and continuous power requirements

Modern controllers can also provide functions such as CAN communication and advanced motor-control algorithms.

Torus Motion's TESC controller family, for example, supports motor types including BLDC, PMSM, AFM and IPM, with different controller series designed around different power requirements.

Motor + controller compatibility should therefore be confirmed before procurement.

7. Choose the Right Motor Technology

Different electric motor architectures have different advantages.

BLDC Motors

Popular in:

• E-bikes
• Scooters
• Light EVs
• Small industrial systems

They offer a relatively simple and efficient solution for many applications.

PMSM Motors

Common in higher-performance EV applications because of their efficiency, controllability and power density.

Axial Flux Motors

Axial flux motors use a different magnetic and mechanical architecture from conventional radial-flux motors.

Their compact form factor and high power density can make them attractive for applications where weight and packaging space are critical.

Torus Motion's V1 and V2 ranges use axial-flux technology, with the company stating that its motors are designed for compact packaging and high power density.

8. Don't Ignore Motor Size and Weight

For an EV, every kilogram matters.

A heavier motor can increase vehicle mass, which can affect:

• Acceleration
• Energy consumption
• Range
• Suspension loading
• Handling
• Packaging

This is especially important in:

Motorsports | eBAJA | Performance EVs | Two-wheelers | Robotics

A compact high-power-density motor can provide greater flexibility when packaging the powertrain.

9. Thermal Management Is Critical

One of the biggest mistakes in motor selection is considering only electrical specifications.

A motor generates heat during operation.

If that heat cannot be removed effectively, the system may experience:

• Thermal derating
• Reduced performance
• Reduced efficiency
• Increased component temperature
• Potential reliability issues

Motors may therefore be available with different cooling architectures.

Air Cooling

Advantages:

• Simple
• Lightweight
• Fewer components
• Lower system complexity

Liquid Cooling

Advantages:

• Better heat transfer
• Suitable for higher continuous loads
• Better thermal control

Torus Motion's V2 range includes both air-cooled and liquid-cooled variants, with the liquid-cooled V2 models offering higher listed peak power than the air-cooled versions.

10. Consider the Duty Cycle

Ask:

How will the vehicle actually be used?

A motor used for short bursts of acceleration has a different requirement from one running continuously for several hours.

For example:

This is why there is no universally "best" EV motor.

There is only the best motor for a particular application.

11. Calculate the Required Power

A basic vehicle calculation can start with the forces acting against the vehicle.

These include:

Rolling Resistance

Fᵣ = Cᵣ × m × g

Aerodynamic Drag

F_d = ½ × ρ × C_d × A × v²

Gradient Force

F_g = m × g × sin(θ)

The total tractive force is approximately:

F_total = Fᵣ + F_d + F_g + m × a

Then:

Wheel Power = F_total × v

This gives the engineering team a starting point for determining the required motor power.

For an actual vehicle design, drivetrain efficiency, transient requirements and thermal limits should also be included.

12. Don't Forget the Controller and Battery

Selecting a motor is only one part of the powertrain.

A complete EV powertrain can be represented as:

Battery → Protection → Contactor → Controller → Motor → Reduction → Wheels

Each component must be compatible.

For example, increasing motor power may require:

• Higher battery current capability
• Higher-rated controller
• Appropriate HV connectors
• Correct contactor rating
• Larger cables
• Improved cooling
• Appropriate battery BMS

This is why evaluating the complete system is better than selecting individual components independently.

13. What About the Torus V2 Motor?

For applications requiring a compact, high-performance electric drive, the Torus Motion V2 series is one option worth evaluating.

According to Torus Motion's current specifications, the V2 series offers:

• 48 / 60 / 72 V configurations
• Up to 15 kW peak power for the air-cooled V2
• Up to 20 kW peak power for the liquid-cooled V2
• Up to 55 Nm peak torque for the air-cooled V2
• Up to 60 Nm peak torque for the liquid-cooled V2
• Up to 95% listed efficiency
• IP67 rating
• Magnetic encoder
• Air- and liquid-cooled options

The V2 series is positioned for applications such as L5 vehicles, performance vehicles, forklifts, tow tugs and other high-power applications.

However, these specifications should be matched against your actual vehicle calculations rather than used as a standalone reason to select the motor.

14. Quick Motor Selection Checklist

Before purchasing an EV motor, make sure you know:

Vehicle

☐ Vehicle weight
☐ Maximum payload
☐ Target top speed
☐ Required acceleration
☐ Maximum gradient

Drivetrain

☐ Wheel diameter
☐ Number of driven wheels
☐ Gear reduction
☐ Differential/transmission

Electrical

☐ Battery voltage
☐ Peak battery current
☐ Continuous battery current
☐ Controller compatibility

Motor

☐ Peak torque
☐ Continuous torque
☐ Peak power
☐ Continuous power
☐ Maximum RPM
☐ Cooling method
☐ IP rating
☐ Weight
☐ Dimensions

Application

☐ Duty cycle
☐ Ambient temperature
☐ Dust/water exposure
☐ Off-road requirements
☐ Space constraints

Conclusion

Selecting an EV motor is an engineering exercise—not simply a product-selection exercise.

The right motor should provide the required torque, power, speed and efficiency while remaining compatible with the battery, controller, drivetrain and thermal-management system.

For a high-performance or industrial EV, the most important question isn't:

"Which motor has the highest power?"

It is:

"Which motor provides the required performance within our vehicle's electrical, mechanical, thermal and packaging constraints?"

That's where proper engineering selection makes the difference.