Automotive & MechanicsElectric Vehicles: High Voltage and Fast Charging
Twenty flashcards on EV high-voltage safety for technicians and the federal rules for fast charging.
Free to start20 cards
- What voltage do EV high-voltage systems typically run at?
- Typically 400 to 1,000 volts.
- When does federal law call an EV part a high voltage source?
- When its working voltage is greater than 30 VAC or 60 VDC.
- What color marks exposed high-voltage cables?
- Orange: cables outside protective barriers must have an orange outer covering.
- What warning symbol goes on the battery?
- A yellow high-voltage symbol with black border and arrow, on or near the energy storage device.
- How fast must a separated high-voltage connector become safe?
- One option in FMVSS No. 305: its live parts drop to 60 VDC or 30 VAC or less within one second.
- What electrical isolation does FMVSS No. 305 require?
- At least 100 ohms/volt for a DC high voltage source and 500 ohms/volt for an AC one.
- What must happen to the high-voltage system in a crash?
- Light-duty vehicles must deactivate or isolate the electrical system when they detect a collision or short circuit.
- What tests do EV battery packs go through?
- Overcharge, vibration, extreme temperatures, short circuit, humidity, fire, collision and water immersion.
- How do responders make an EV electrically safe?
- With cutoff switches or other methods to isolate the battery, following the manufacturer's emergency response guide.
- What fire risk remains after an EV battery fire is out?
- Delayed ignition or reignition, even after it is believed to be extinguished.
- When does the newer FMVSS No. 305a become mandatory?
- September 1, 2027 for vehicles of 4,536 kg GVWR or less; September 1, 2028 for heavier ones.
- How fast must a car warn of a battery thermal event?
- Within three minutes of its onset, with sound and light signals that stay on for at least 5 minutes.
- What fire rule applies after a crash test under FMVSS No. 305a?
- No fire or explosion from impact until one hour after the test sequence ends.
- Why do all-electric vehicles need less maintenance?
- Fewer fluids, much less brake wear thanks to regenerative braking, and far fewer moving parts.
- What training must a federally funded charger electrician have?
- EVITP certification, or an electrician registered apprenticeship that includes charger-specific training.
- What is Level 1 charging?
- A 120 V AC plug, giving about 5 miles of range per hour of charging.
- What is Level 2 charging?
- 240 V at home or 208 V commercial, about 25 miles of range per hour, from 2.9 to 19.2 kW.
- How fast is DC fast charging?
- Up to 500 kW, about 100 to 200+ miles of range per 30 minutes.
- What must a federally funded corridor fast-charging station offer?
- At least four DC fast ports charging at once at up to 150 kW each, with uptime greater than 97%.
- What is the SAE J3400 connector?
- The standard based on Tesla's NACS plug, published as a report in December 2023; federal chargers may add it next to CCS1.
Official sources
Maintenance and Safety of Electric Vehicles
49 CFR 571.305: Standard No. 305, Electric-powered vehicles: electrolyte spillage and electrical shock protection
49 CFR 571.305a: Standard No. 305a, Electric-powered vehicles: electric powertrain integrity
23 CFR Part 680: National Electric Vehicle Infrastructure Standards and Requirements
Electric Vehicle Charging Stations
SAE J3400 Charging Connector
Making Synapses is not affiliated with, sponsored by or endorsed by the California Department of Motor Vehicles, the Georgia Department of Driver Services or any state agency. Agency names are named only to describe the content.