EV Terminology: 17 Tidbits You Should Know

Change can be difficult, as in the switch to electric vehicles (EVs). Fortunately, once you learn a few vocabulary words, it’s easier than it seems. That’s the goal of this little exercise in EV terminology. Because it’s oversimplified, I highly recommend if you’re already knowledgeable in this arena, you click away immediately.

 

Electric vehicle

We’ll start with the absolute basics. Technically, this term refers to any vehicle propelled in part or in full by an electric motor. To avoid confusion, I’ll stick to vehicles that run solely on a battery-powered electric motor. In any event, the point is that the traditional internal combustion engine—which relies on the combustion of refined crude oil to generate energy—is not part of the picture.

 

Lithium

The key element in the rechargeable lithium-ion batteries that make this post about EV terminology possible.

 

Volt (V)

The unit used to express voltage, a measurement of electrical force. An analogy is commonly made to water pressure in plumbing. This is the first concept needed to understand battery charging (more on that below).

 

Amp (or ampere)

A measurement of electrical current, specifically the number of electrons passing a given point per second. An analogy is commonly made to the flow rate of water in plumbing. (Typically, but not always, the greater the voltage, the greater the current.) This concept will also show up with regards to charging.

 

Alternating current (AC)

Without getting too technical, this is the electrical standard used in homes.

 

Direct current (DC)

Again, without getting too technical, this is the electrical standard used in EVs (and most modern electronics). EVs have an on-board charger that converts AC to DC and allows for the battery to be charged.

 

Watt (W)

A measurement of electrical power, specifically work performed per second. If you multiply volts times amps, you get watts. (And if you divide that by 1000, you get kilowatts—see below.) If this doesn’t really make sense, don’t worry. Just roll with it.

 

Kilowatt

Abbreviated kW, this is the equivalent of 1000 watts. Kilowatts show up in a couple different spots. One is to express the power of a charger, and the other is to express the power of an electric motor (with one kilowatt being equal to 1.34 horsepower).

 

Kilowatt-hour

Because power is technically a rate, it must be multiplied by a unit of time to express energy. And that’s where a kilowatt-hour (kWh) comes into play—it’s the amount of energy used when one kilowatt of power is maintained for one hour. The capacity of EV batteries is expressed in kilowatt-hours (much like the capacity of a gas tank is expressed in gallons).

 

Miles per gallon equivalent

MPGe is a measurement of how far a vehicle can travel with 33.7 kWh, the amount of energy in one gallon of gas. It’s quite common to find vehicles with an MPGe over 100, and many have thus disputed the importance of this measurement.

 

Miles per kilowatt-hour

MPkWh is self-explanatory, as in the number of miles a vehicle can travel on one kilowatt-hour of energy, serving as a way of expressing EV efficiency (the higher the number the better). Just to confuse everyone with more EV terminology, you might also see a similar concept expressed as kWh per 100 miles, or even Wh (watt-hours) per mile, in which case a lower number would be more desirable.

 

Range

This one is easy, as in the distance in miles that can be expected on a fully-charged battery.

 

Level 1 charging

The charging available from a standard household outlet (a 120-volt outlet using AC). Topping out at perhaps 15 amps, the power delivered is around 1,800 watts (120 x 15) or 1.8 kW, meaning that fully charging a battery with a capacity of 60 kWh will take about 33 hours (60 ÷ 1.8).

 

Level 2 charging

The charging available from a 240-volt circuit (AC) similar to that used for an electric stove or clothes dryer. Assuming about 48 amps, the power delivered is 11,520 watts (240 x 48) or 11.5 kW, meaning a 60 kWh battery could be charged in around 5 hours (60 ÷ 11.5).

 

Level 3 charging

This method of DC charging—which bypasses the on-board charger—works at 480+ volts and upwards of 100 amps, amounting to impressive power that can charge a battery in under an hour (hence the term fast charging). Tesla superchargers fall in this category.

 

Regenerative breaking

A mechanism whereby EVs are able to convert the momentum from a slowing vehicle into energy that can be stored (and used) by the battery.

 

Bidirectional charging

A concept that refers to the use of specialized chargers that actually allow for an EV battery to deliver electricity to a wide variety of entities such as portable appliances, homes (in place of generators), or even energy grids (as a way for an EV owner to make extra income).

 

And with that, it’s time to go fill up gas.