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EV Glossary


Below are definitions of many terms commonly used in the EV community.Some basic electrical concepts and terms may also be found at Electricity Basics, including amps,volts, watts, farads, etc.

Term Definition
AC Alternating Current
AFV Alternate Fuel Vehicle — A vehicle powered by fuel other than gasoline or diesel. Examples of alternative fuels are electricity, hydrogen, and CNG. Additional EAA information on AFVs is below.
Ah Amp Hour — a measure of current (measured in amperes drawn over time (measured in hours), typically used to describe battery capacity and battery charging or discharging.
AT PZEV Advanced Technology PZEVs — AT PZEVs meet the PZEV requirements and have additional "ZEV-like" characteristics. A dedicated compressed natural gas vehicle, or a hybrid vehicle with engine emissions that meet the PZEV standards would be an AT PZEV.
BEV Battery Electric Vehicle— An EV powered by electricity stored in batteries.
Cnare a series ofn-hour battery charge/discharge test specifications from the SAE. Battery charge/discharge rates affect storage capacity; see Peukert's Law below for a reference.
CARB California Air Resources Board
CNG Compressed Natural GasNatural gas is primarily methane (CH4). To serve as a vehicle fuel, it must be stored at high pressure (i.e. compressed) to get sufficient amounts in a tank.
DC Direct Current
E85 E85 is a blend of 85% ethanol and 15% gasoline by volume.
EV Electric Vehicle — a vehicle where an electric motor powers the wheels. Battery EVs store electric power in batteries. Hybrid EVs supplement battery storage with electricity generated from another fuel (e.g. gasoline or diesel ICE). Fuel cell EVs supply electricity to the motor from a fuel cell. Additional EAA information on EVs is below.
Fuel Cell Fuel cells convert fuel directly into electricity. The most common type is a PEM, which converts gaseous hydrogen (H2) into electricity and water (H2O).
FCV Fuel Cell Vehicle Additional EAA information on FCVs is below.
FFV Flexible Fuel Vehicle— a vehicle that can run on a variety of fuels (most often just gasoline and E85)
GHG Green House Gas— A gas that in the atmosphere prevents heat from radiating back into space, and thus warms the earth (the greenhouse effect). Carbon dioxide (CO2) is the most common greenhouse gas. Methane (CH4) is another GHG, and has approximately twenty times the greenhouse effect as COin the atmosphere.
HEV Hybrid Electric Vehicle— A vehicle that combines conventional power production (e.g. an ICE) and an electric motor. Additional EAA information on HEVs is below.
HOV High Occupancy Vehicle
HP Horsepower— a measure of power (power is energy per time). For engines this is torque multiplied by rotational speed. In the automotive world, it is used to rate engines, but comparisons based on engine horsepower can be misleading because torque varies significantly with RPM for an ICE and the test conditions of the measurement must be carefully specified (e.g. SAE test procedures). In contrast, for electric motors, horsepower is simply defined as 746 Watts (0.746KW).
Hz Hertz— cycles per second, a measure of AC frequency. The U.S. AC electric grid is 60Hz.
ICE Internal Combustion Engine— An engine that burns fuel inside a reaction chamber to create pressure inside the chamber that is converted into rotary motion. ICE engines are typically based on the Otto cycle,Atkinson cycle, or Wankel engine.
KW KiloWatt— a measure of power (power is energy per time).
KWh KiloWatt Hour— a measure of energy.
LEV Low Emission Vehicle — All new cars sold in California starting in 2004 will have at least a LEV or better emissions rating.
LiIon Lithium Ion— a battery technology consisting of several different chemistries, with different characteristics.
LSV Low Speed Vehicle — another name for Neighborhood Electric Vehicles rating, not typically permitted on highways..
NEMA National Electrical Manufacturers Association— Typically used in the EV community when referring to plug and receptacle types, such as ones at NEMA Plug & Receptacle Configurations.
NEV Neighborhood Electric Vehicle-not typically permitted on highways.
NOx Nitrogen oxides formed whenever combustion occurs in the presence of nitrogen
NiMH Nickel Metal Hydride— a battery technology which pre-dates modern Lithium chemistries.
PbA Lead Acid— a battery technology dating back to the earliest 20th century. .
PEM Proton Exchange Membrane— a type of fuel cell.
Peukert's Law estimates the capacity of an electric battery over a range of discharge rates. See Wikipedia Peukert's law for more information.
PHEV Plug In Hybrid Electric Vehicle Additional EAA information on PHEVs is below.
PV Photovoltaic(think rooftop solar)
PZEV Partial Zero Emissions Vehicle— PZEVs meet SULEV tailpipe emission standards, have zero evaporative emissions and a 15 year / 150,000 mile warranty. No evaporative emissions means that they have fewer emissions while being driven than a typical gasoline car has while just sitting.
RMS Root Mean Square— typically used to characterize an AC waveform. An AC waveform of N RMS Volts generates the same heat in a resistor as N Volts DC. For a sine wave, such as found in the electric grid, the RMS voltage is 0.707 times the peak voltage (i.e. your 120V AC outlet has a peak voltage of 169V, but is equivalent in heating value to 120V DC).
RPM Revolutions Per Minute
SAE Society of Automotive Engineers
SOx Sulfur oxides
SPI Small Paddle Inductive — Inductive coupling of power from the charger to the vehicle was put on various production vehicles in two generations: first with a large paddle and then later with a small paddle. Large paddle cars can use small paddle chargers with an adapter, but the converse is not true, so SPI chargers are now much preferable to LPI.
SULEV Super Ultra Low Emission Vehicle— SULEVs are 90% cleaner than the average new model year car.
ULEV Ultra Low Emission Vehicle — ULEVs are 50% cleaner than the average new model year car.
VOC Volatile Organic Compounds
WTP Wells to Pump — the first part of WTW— the part that is often overlooked when comparing different automotive technologies.
WTW Wells to Wheels — a designation that something (e.g. pollution, energy, etc.) is being measured from extraction of raw materials (e.g. petroleum — hence Wells) to the wheels of the vehicle. This is the most appropriate way to measure most end-to-end effects in transportation. Additional EAA information on WTW is below.
ZEV Zero Emissions Vehicle— ZEVs have zero tailpipe emissions are 98% cleaner than the average new model year vehicle. These include battery electric vehicles and hydrogen fuel cell vehicles.

Vehicle Classifications

EV, Electric Vehicle

EVs are generally cars, trucks or vans that performs the same functions as a conventional fueled vehicle — highway speeds, safety, etc. However, batteries are the storage means for the "fuel" and the vehicle is refueled directly from electricity by plugging into a special charger or wall socket. An EV can be created by converting a vehicle (such as a conventional gas car, to be powered by an electric motor and controllers) or it may have been produced directly from a company as an EV (such as the GM EV-1, Toyota RAV4-EV, CommuterCarsTango, or Myers Motors).

nEV, neighborhood EV

NEVs operate below highway speeds — typically with a maximum speed of under 30mph. Not for highway use, but just fine for surface streets.

HEV, Hybrid Vehicle

Hybrid vehicles (HEVs)have electric components, but use a fuel source (such as gasoline) to power the vehicle. The batteries can only be recharged by operating the vehicle (e.g., no plug). This is a growing market segment and many established auto manufacturers are producing hybrid vehicles today. The most conservative estimate for 2010 and beyond has J.D. Power forecasting a plateau of three percent hybrid penetration in the U.S. market. The most optimistic and forward-looking prediction comes from Booz Allen Hamilton, a global strategy and technology-consulting firm. They predict that hybrid cars will make up 80 percent of the overall car market by 2015. (source for sales estimates:

PHEV, Plug-in Hybrid Vehicle

Plug-in hybrid vehicles (PHEVs)have additional features built onto an HEV (bigger battery pack) that will enable significant range (30-60 miles) on "all electric" mode. In addition, the batteries can be recharged by plugging the vehicle into any wall socket. The EAA has launched the Plug-in Hybrid Electric Vehicle (PHEV) SIG to develop and document the modifications needed to convert hybrid electric vehicles to increase their battery capacity and allow them to charge from an external source of electricity. The goal is to increase their electric-only range and reduce gasoline consumption. The Plug-in Hybrid Electric Vehicle (PHEV) SIG will eventually make conversion plans available as well as a list of parts needed. Initial target vehicle: 2004-2006 Toyota Prius.
The Chevy Volt is also a PHEV, although GM has used the EREV label for extended range electric vehicle instead..
For more information see: Another organization,, is a coalition of RAV4 EV drivers, former Honda EV+, GM EV1, and Ford Th!nk City lessees, and clean air and energy independence advocates. PIA is a special focus EAA chapter and advocates the use of plug-in cars, trucks and SUVs powered by cleaner, cheaper, domestic electricity to reduce our nation's dependence on petroleum and improve the global environment. PIA promotes Battery Electric and Plug-in Hybrid vehicles for the public to drivetoday.

Check out the following web sites for more information about PHEVs:

FCV, Fuel Cell Vehicle

Fuel Cell Vehicles (FCVs)have an electric drive train, but use a fuel cell, not the grid, to power the vehicle. Some of these vehicles also store a portion of their energy in batteries. Only prototype FCVs are currently available (under lease to governments or businesses). Hydrogen is stored in specialized tanks onboard the vehicle and vehicle refueling would take place at specialized refueling centers (that are not widely available today). Hydrogen is not technically a fuel, it is an energy carrier, and is the most abundant and simplest known element. The hydrogen to power a fuel cell must first be separated from other materials — water, biomass, natural gas, etc. It takes about four times more energy to separate the hydrogen from a source and then use it to power a vehicle compared to the energy used to power a BEV.

AFV, Alternate Fuel Vehicle

Alternative Fuel Vehicles (AFVs)can be EVs, or vehicles that use fuel other than gas or diesel. Examples include vehicles that run on compressed natural gas (CNG), ethanol, methanol, bio-diesel, etc. Some vehicles are bi-fuel and offer the ability to store and switch between two separate fuel sources. The Clean Cities Program sponsored by the US Department of Energy also provides good information about alt fuel vehicles.

Wells to Wheels

Many comparisons between traditional gasoline-powered vehicles and alternatives look only at effects of the vehicle itself, and ignore the effects of producing fuel for the vehicle. This is remedied by "Wells to Wheels" calculations that include all relevant steps required to provide motive force to a vehicle, including:

  • extraction of raw materials (e.g. petroleum or coal)
  • transportation (getting the raw materials to processing facilities (e.g. oil tankers or railroad)
  • processing (e.g. refining or electric power production)
  • more transportation (e.g. delivery of gasoline to the pump or electric power transmission)
  • vehicle efficiency from its fuel, which may include
    • fuel storage efficiency
    • conversion of the fuel into power in the engine
    • efficiency of getting engine power to the wheels (e.g. vehicle transmission systems)

Wells to Wheels calculations fairly address the bogus complaint that EVs only move pollution problems rather than solve them. Yes, electric power plants pollute, but then so do refineries. Only by comparing the entire fuel chain can an intelligent comparison be made. By almost every measure, EVs come out ahead.

Argonne National Laboratories, a publicly-funded US Research Lab, has developed a public domain spreadsheet model to profile greenhouse gas emissions and net energy usage for various transportation modes. TheVancouver Electric Auto Associationhas an excellentsummary of energy efficiencystudies completed by Argonne National Laboratories