Maintenance and Safety of Hybrid and Plug-In Electric Vehicles

Photo of the inside of a hybrid electric vehicle engine.

HEVs and PHEVs require the same general maintenance as conventional vehicles, but EVs require less maintenance because they have fewer moving parts and fluids to change.

Maintenance needs and safety requirements for hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) are similar to those of conventional vehicles, while all-electric vehicles (EVs) require less maintenance. Manufacturers are designing these vehicles and publishing guides with maintenance and safety in mind.

Maintenance Comparison

Because HEVs and PHEVs have internal combustion engines, maintenance requirements are similar to those of conventional vehicles. The electrical system (battery, motor, and associated electronics) will likely require minimal scheduled maintenance. Due to the effects of regenerative braking, brake systems on these vehicles typically last longer than those on conventional vehicles.

EVs typically require less maintenance than conventional vehicles because:

  • The battery, motor, and associated electronics require little to no regular maintenance
  • There are fewer fluids to change
  • Brake wear is significantly reduced due to regenerative braking
  • There are far fewer moving parts relative to a conventional gasoline engine.

Battery Maintenance

The advanced batteries used in these vehicles have a limited number of charging cycles (the number of times the battery can be charged and discharged, also called "cycle life"). Check with the dealer about battery life and warranties and consider the manufacturer's battery recycling policy. Some automotive battery systems utilize liquid coolant to maintain safe operating temperatures. These systems may require regular checks. Ask your dealer or refer to your owner's manual for more information.

The batteries in electric-drive vehicles are generally designed to last for the expected lifetime of the vehicle. The Toyota Prius HEV, which has been sold in the United States since 2001, has experienced less than 0.003% battery failures (source: Several manufacturers offer 8-year/100,000 mile warranties for their EV and PHEV batteries.

Manufacturers have not published pricing for replacement batteries, but if the battery does need to be replaced outside the warranty, it is expected to be a significant expense. However, battery prices are expected to decline as technology improves and production volumes increase.

Safety Requirements

Commercially available electric-drive vehicles must meet the Federal Motor Vehicle Safety Standards and undergo the same rigorous safety testing as conventional vehicles sold in the United States. The exception is neighborhood electric vehicles, which are subject to less-stringent standards because they are typically limited to roadways specified by state and local regulations.

HEVs, PHEVs, and EVs have high-voltage electrical systems that typically range from 100 to 600 volts. Their battery packs are encased in sealed shells and meet testing standards that subject batteries to conditions such as overcharge, vibration, extreme temperatures, short circuit, humidity, fire, collision, and water immersion. Manufacturers design these vehicles with insulated high-voltage lines and safety features that deactivate the electrical system when they detect a collision or short circuit. EVs tend to have a lower center of gravity than conventional vehicles, making them more stable and less likely to roll over.

Emergency Response and Training

Emergency response for electric drive vehicles is not significantly different from conventional vehicles. Electric drive vehicles are designed with cutoff switches to isolate the battery and disable the electric system, and all high-voltage power lines are clearly desginated by being colored orange.

Manufacturers publish emergency response guides for their vehicles and offer training for emergency responders. The National Fire Protection Association has training and information resources available at Find a list of education and training programs with contact information in Electric Vehicle Workforce Education & First-Responder Training Programs.