1. What is the EV Motor Power Equation?

The EV motor power equation calculates the required power for an electric vehicle based on its mass, desired acceleration, target velocity, and drivetrain efficiency. This helps in selecting an appropriately sized motor for the vehicle.

2. How Does the Calculator Work?

The calculator uses the motor power equation:

Where:

• \( P \) — Required motor power (Watts)
• \( Mass \) — Vehicle mass in kilograms
• \( Acceleration \) — Desired acceleration in m/s²
• \( Velocity \) — Target velocity in m/s
• \( \eta \) — Drivetrain efficiency (0-1)

Explanation: The equation calculates the power needed to accelerate a given mass to a certain velocity, accounting for energy losses in the drivetrain.

3. Importance of Motor Sizing

Details: Proper motor sizing is crucial for EV performance. An undersized motor won't provide adequate acceleration, while an oversized motor adds unnecessary weight and cost.

4. Using the Calculator

Tips:

• Mass should include vehicle weight plus maximum payload
• Typical acceleration for passenger EVs: 0.3-0.5g (3-5 m/s²)
• Highway velocity is typically 28-36 m/s (100-130 km/h)
• Typical drivetrain efficiency: 0.85-0.95

5. Frequently Asked Questions (FAQ)

Q1: How does this relate to continuous vs peak power?
A: This calculates peak power needed for acceleration. Continuous power for cruising is typically much lower.

Q2: What about aerodynamic drag and rolling resistance?
A: This is a simplified model. For precise calculations, add drag (½ρv²CdA) and rolling resistance (Crr×mass×g).

Q3: How to convert kW to horsepower?
A: Multiply kW by 1.341 to get horsepower (hp).

Q4: What's typical motor size for a passenger EV?
A: Most modern EVs have motors between 100-300 kW, with performance models up to 500+ kW.

Q5: How does battery capacity affect this?
A: Battery capacity determines range, not peak power. However, the battery must be able to deliver the required current.