Battery and EV Powertrain (Diploma) Quiz, EV Technician

Question 1

What is the primary function of an inverter in an electric vehicle powertrain during propulsion?

Accepted Answer

It converts DC power from the battery into AC power to generate a rotating magnetic field in the electric traction motor.

Answer

It converts high-voltage DC directly into low-voltage DC for headlight operation.

Answer

It converts AC power from the motor into DC power for the wheels.

Answer

It converts mechanical energy directly into hydraulic pressure for dynamic braking.

Question 2

Which daily charging range is recommended to optimize the service life of a lithium-ion EV battery pack?

Accepted Answer

20-80%

Answer

0-100%

Answer

0-50%

Answer

50-100%

Question 3

What is the resting Open Circuit Voltage (OCV) of a fully charged, healthy 12V auxiliary battery in an electric vehicle?

Accepted Answer

12.6V to 12.8V

Answer

12.0V to 12.2V

Answer

10.0V to 11.5V

Answer

13.8V to 14.4V

Question 4

Which sequence correctly describes the flow of power during EV propulsion?

Accepted Answer

Battery -> Inverter -> Electric Motor -> Reduction Gear -> Wheels

Answer

Wheels -> Reduction Gear -> Electric Motor -> Inverter -> Battery

Answer

Battery -> Electric Motor -> Inverter -> Reduction Gear -> Wheels

Answer

Inverter -> Battery -> Reduction Gear -> Electric Motor -> Wheels

Question 5

What action does the Battery Management System (BMS) take when high-voltage power is demanded for vehicle propulsion?

Accepted Answer

It permits high-voltage DC power to flow from the battery pack to the main distribution lines.

Answer

It steps down 400V DC directly to 12V DC for auxiliary lights.

Answer

It mechanically locks the reduction gear during acceleration.

Answer

It converts AC electrical power into mechanical torque.

Question 6

According to standard safety protocols for high voltage EV maintenance, what must a technician do immediately after isolating the high voltage system per OEM instructions?

Accepted Answer

Wear insulated PPE and verify zero voltage before beginning work.

Answer

Perform a full capacity discharge test on the battery.

Answer

Drain all coolant fluid from the thermal loop.

Answer

Recharge the 12V auxiliary battery to full capacity.

Question 7

What operational issue can occur if an electric vehicle's 12V auxiliary battery fails, even if the main high-voltage traction battery is 100% charged?

Accepted Answer

The high-voltage system can be prevented from powering on.

Answer

The traction motor will overspeed beyond its rated RPM limits.

Answer

The inverter will bypass safety fuses and supply unregulated power.

Answer

The vehicle can run only at reduced mechanical reverse speeds.

Question 8

What electrical conversion occurs in the inverter during vehicle propulsion mode?

Accepted Answer

DC to AC conversion

Answer

AC to AC frequency modulation only

Answer

DC to DC voltage step-up only

Answer

AC to DC conversion

Question 9

An EV technician measures a resting Open Circuit Voltage (OCV) of 12.2V on a 12V auxiliary battery. What does this voltage reading indicate?

Accepted Answer

Partial discharge of the auxiliary battery

Answer

Cell thermal runaway condition

Answer

Internal short circuit in the traction pack

Answer

Normal fully charged auxiliary battery state

Question 10

What is State of Charge (SoC) in an electric vehicle battery pack?

Accepted Answer

The ratio of actual stored charge to maximum charge level

Answer

The ratio of cell weight to total battery pack weight

Answer

The ratio of peak discharge voltage to resting open circuit voltage

Answer

The ratio of DC current input to AC current output

Battery and EV Powertrain (Diploma) Quiz, EV Technician

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