Mixed Deck — All EVT Topics Flashcards

Under NFPA 70 (NEC), Article 625 governs EV charging equipment. What minimum clearance is typically required between an outdoor EVSE and a building's gas meter?

Answer: 3 feet

NEC Article 625 and local codes generally require a minimum 3-foot clearance between EVSE installations and gas service meters to reduce ignition risk.

A shop receives a flood-damaged EV with a submerged battery pack. According to safety best practices and regulatory guidance, what is the first priority?

Answer: Quarantine the vehicle outdoors away from structures due to thermal runaway risk

Flood-damaged lithium-ion batteries are at high risk of delayed thermal runaway; the vehicle must be quarantined outdoors, away from buildings, pending manufacturer guidance.

Which international standard defines electrical safety requirements for electric road vehicles, including HV wiring protection?

Answer: ISO 6469

ISO 6469 is the international standard specifying electrical safety requirements for electrically propelled road vehicles, covering HV wiring, isolation, and protection measures.

What does energy density refer to in batteries?

Answer: The energy storage capacity relative to size or weight

Energy density in batteries refers to the amount of energy a battery can store per unit of volume (Wh/L) or per unit of mass (Wh/kg). A higher energy density means the battery can store more energy in a smaller or lighter package, which is crucial for electric vehicles to achieve longer ranges without excessive weight.

Why are safety standards critical in EV maintenance?

Answer: They protect both workers and equipment

Safety standards in EV maintenance are paramount due to the high voltages and unique components involved. Adhering to these standards, which include proper lockout/tagout procedures, personal protective equipment (PPE), and specialized tools, is crucial for preventing electric shock, arc flash incidents, and damage to expensive EV components. Ultimately, these standards protect both technicians and the vehicle itself.

What does applying a lockout/tagout (LOTO) procedure during EV high-voltage service ensure?

Answer: The HV system cannot be accidentally re-energized while a technician is working on it

LOTO procedures physically lock the MSD in the removed position and apply a tag, preventing any other person from re-energizing the HV system while a technician is actively working on it.

How should a technician approach troubleshooting an intermittent fault?

Answer: Use data logging and replicate conditions

Intermittent faults are challenging because they don't occur consistently, making direct diagnosis difficult. The most effective approach is to use data logging to capture system parameters when the fault does occur and then attempt to replicate those specific conditions in a controlled environment. This systematic method helps pinpoint the root cause by observing the system's behavior during the fault's manifestation.

Which risk management approach is MOST effective for EVT professionals when evaluating potential workplace hazards?

Answer: Proactive hazard identification and assessment

Proactive hazard identification and assessment allows professionals to identify and mitigate risks before incidents occur, which is far more effective than reactive approaches that only address problems after they happen.

An EV's thermal management system shows the battery coolant temperature rising rapidly during DC fast charging. The coolant pump is confirmed operational. What is the NEXT component to check?

Answer: The battery chiller (heat exchanger) and refrigerant charge in the thermal circuit

If the pump is working but temperature still rises, the battery chiller or refrigerant circuit is likely not removing heat effectively from the coolant loop.

A battery pack uses passive balancing. What happens to excess energy from high-SOC cells during balancing?

Answer: It is dissipated as heat through resistors

Passive balancing bleeds excess charge from higher-SOC cells by dissipating energy as heat through bleed resistors, equalizing SOC without energy transfer.

Which sensor input does a BMS use to implement temperature-derated charging limits?

Answer: Thermistors or thermocouples placed within the battery module

BMS systems use thermistors or thermocouples embedded in battery modules to monitor cell temperatures and apply charge/discharge derating when temperatures exceed safe limits.

How should Certified Electric Vehicle Technician professionals handle equipment that shows signs of malfunction during operation?

Answer: Immediately cease operation, secure the equipment, and report the malfunction

When equipment malfunctions, immediate cessation of operation is required to prevent safety hazards, further equipment damage, or compromised results. The equipment should be secured and the malfunction reported for proper maintenance.

What is the primary benefit of adopting technology in professional practice?

Answer: Improved efficiency, accuracy, and the ability to scale operations

Technology adoption in professional practice primarily improves efficiency, enhances accuracy, and enables scalability of operations while supporting human decision-making.

What is the primary purpose of cell balancing in a multi-cell battery pack?

Answer: To ensure all cells reach the same state of charge to maximize usable capacity

Cell balancing ensures every cell in the pack operates at the same SOC, preventing weak cells from limiting overall pack capacity and extending pack life.

Which component regulates power flow from the battery to the motor?

Answer: Power inverter

The power inverter is a crucial component in an electric vehicle's powertrain. Its primary role is to convert the direct current (DC) stored in the battery pack into alternating current (AC) to power the electric motor. It also controls the frequency and voltage of the AC power, thereby regulating the motor's speed and torque.

When an EV is towed after a collision, what towing method should be used if the drive wheels cannot be lifted?

Answer: Flat-bed towing only, or use a dolly under the drive wheels

Rolling drive wheels spin the motor and can generate back-EMF into the inverter or charge the HV battery unexpectedly; a flatbed or dolly eliminates this risk.

What distinguishes a Certified Electric Vehicle Technician certified professional from a non-certified practitioner?

Answer: Certification validates competency through standardized assessment against established benchmarks

Certification provides objective validation of competency through standardized assessment. While non-certified practitioners may be skilled, certification offers verified evidence that a professional meets established benchmarks for knowledge and performance.

What is the primary purpose of the manual service disconnect (MSD) in an EV high-voltage system?

Answer: To physically interrupt the HV circuit for safe servicing

The MSD physically breaks the HV circuit, de-energizing the system and allowing technicians to safely service HV components.

An EV's BMS activates a 'high voltage interlock loop' (HVIL) fault and disconnects the pack contactors. What does this indicate?

Answer: A break in the high-voltage connector safety loop has been detected, indicating an open circuit or connector issue

The HVIL is a series safety circuit through HV connectors; a fault means the loop is broken, indicating an open HV connector, damaged wiring, or a cover removed from a HV component.

What property of lithium iron phosphate (LFP) chemistry makes it particularly safe compared to NMC?

Answer: Thermally stable cathode that does not release oxygen during thermal runaway

LFP's iron-phosphate cathode is highly thermally stable and does not release oxygen when heated, greatly reducing fire risk during thermal runaway compared to NMC.