The Language of Electric Vehicles
If you’re new to electric vehicles (EV), understanding the technology and terminology can sometimes feel confusing. After all, the internal combustion engine (ICE) in gasoline-powered vehicles has been around for over 130 years, and many people have a basic understanding of how they work. For electric cars, terms like horsepower, gallons, and miles per gallon are replaced with volts, amps, kW, kWh, and miles/kWh.
The good news is that the basics of EV technology are relatively straightforward – since EVs actually have fewer components and moving parts. And as an EV owner, you will only need to understand the fundamentals of EV technology and the basic terms that describe power, capacity, charging, and efficiency.
Whether you’re shopping for your first EV or just starting your EV ownership journey, here’s an easy guide to help you understand the most common EV terms.
Electric Vehicle Basics
Let’s first go over the basic workings of an EV. If you’ve ever played with a remote controlled (RC) car as a kid, you likely already have the fundamentals.
A battery-electric vehicle (BEV) has four key components:
- The electric motor(s)
- The main battery pack, also known as the traction battery
- The charging system
- Various electronic control units
When you plug a charger into an electric vehicle, you are using the charging system to charge the main battery pack. The battery pack is essentially an EV’s fuel tank, which stores energy in the form of electricity. The energy stored in the battery pack powers the electric motor(s) that propels the vehicle. There are various electronic control units that manage the charging, battery, accessories, and drivability of the vehicle.
In a plug-in hybrid electric vehicle (PHEV), the same basic EV components exist, in addition to an internal combustion engine and fuel tank. Conventional hybrid-electric vehicles (HEVs) also have the same basic EV components as a PHEV, but do not have the ability to charge using an external charger.
Electricity Basics
You don’t need to be an electrical engineer or remember your high school physics to understand electricity. The easiest way to think about electricity is to use a water analogy.
Electricity is essentially the flow of charged particles called electrons. These electrons flow from one source to another, such as from your charger to the EV battery, and then to the electric motor. The cables and wires act like hoses for the electrons to flow through.
The flow of electrons is analogous to the flow of water. Imagine using your garden hose to fill a bucket. You use the faucet to control the flow and pressure of water. Water flows through the hose and into the bucket. The water will fill the bucket at different rates and to a determined capacity. When you charge your EV at home, the charger (faucet) controls the electrons that flow from your home’s electrical power source, through the cable (hose) and to the EV’s battery (bucket).
Voltage
As an EV driver, you’ll come across the term voltage. Voltage, measured in volts (V), is the amount of pressure associated with electricity. The higher the voltage, the higher the amount of pressure that “pushes” the electrons through a wire.
Going back to our water analogy, when you fully open the faucet, the water pressure is high as it enters the hose. The water pressure can also change by using the faucet, different hose sizes, pumps, and gravity. Similarly, electrical voltage can vary depending on the vehicle design and source of electricity.
When you use a Level 1 charger, it operates at 110 volts. In contrast, a Level 2 charger operates at 240 volts. The higher voltage of the Level 2 charger allows for faster charging of your EV.
Most modern battery-electric vehicles use a 400-volt system. EVs like the Hyundai Ioniq 5 and Kia EV6 use an 800-volt design. The higher voltage allows for faster charging because of they allow a higher pressure of electricity.
Amps (A)
Amps (A), short for ampere, is a measure of the strength of an electrical current. Essentially, it’s the rate of flow that the electrons move through a wire or circuit.
The rate of the electrons flowing through a wire is like the rate of water flowing through a hose. The faster the flow of water through the hose, the faster you’ll fill the bucket. The faster the flow of electricity, the higher the amperage.
If you look at your home’s electrical breaker panel, you’ll likely see different circuit breakers for 15A, 20A, 30A, 40A. The higher the amperage, the more electricity can flow through the circuit.
One of the main differences of Level 2 home chargers is their amperage. In general, a 48 A charger can charge an EV battery at a faster rate than a 30A charger. Some Level 2 chargers can go as high as 80 A, and can be useful if you have an EV with a very large battery. Your EV model and home’s electrical power will help determine the amperage needed for a Level 2 home charger.
Kilowatt (kW)
A watt (W) is a measure of energy or power of electricity. A kilowatt (kW) is a measure of watts in thousands.
In our water analogy, this can be seen as the amount of power that the water has when it exits the hose. Fully turning on the faucet increases the pressure of water (voltage), which allows the water to flow at a high rate (amps) through the hose. This results in a high amount of power (kilowatts) that the water has as it exits the hose.
In your home, you’ve probably noticed that some of your light bulbs are 40 W, 60 W or 100 W. This is an indication of the amount of electrical power that the light bulb uses. A 100 W light bulb uses more energy and will be brighter than a 40 W bulb.
You’ll likely come across kilowatts in a few different areas as an EV owner. Auto manufacturers sometimes communicate the power of the vehicle’s electric motor(s) in kilowatts. This is similar to how the power of an internal combustion engine measured in horsepower. In fact, 1 kW is equivalent to 1.34 horsepower. For example, a Hyundai Ioniq 5’s single motor makes 125 kW in power; this is equivalent to 167 horsepower.
You’ll also see EV charging measured in kilowatts. A Ford F-150 Lightning pickup truck has a peak DC charging rate of 150 kW, whereas a Chevrolet Bolt has a peak DC charging rate of 55 kW. These figures indicate the highest amount of electrical power that each vehicle can absorb at any given time. With its higher peak charging rate, the F-150 Lightning can accept more electrical energy than the Bolt.
When using a Level 3 DC fast charging station, you’ll notice that different chargers have different energy ratings. You’ll likely see chargers with ratings of 50 kW, 100 kW, 150 kW, or 350 kW, which indicates the power of the charger. In general, a 350-kW charger provides much more energy to a vehicle than a 50-kW charger. The actual amount of energy delivered to your vehicle depends on many factors, including the vehicle’s charging system and your battery’s state of charge.
Kilowatt-hour (kWh)
Not to be confused with a kilowatt (kW), a kilowatt-hour (kWh) is simply the measure of storage for the electrical energy.
Think of kWh as the EV equivalent of gallons of gasoline. A gas-powered vehicle stores gasoline in gallons or liters in its fuel tank. An EV stores electrical energy in kWh in its battery. In our water analogy, this is a measure of the amount of water in the bucket.
When comparing different EVs, one of the most notable differences is the battery size. EVs are available in a variety of battery sizes. The Ford F-150 Lightning battery-electric truck is available with a 131-kWh battery. By comparison, the Chevrolet Bolt battery-electric has a 65-kWh battery.
Some models come with either a standard-range battery or a long range battery. The standard range Hyundai Ioniq 5 battery-electric is 58 kWh. The long range trim comes with a 77.4-kWh battery. In general, the larger kWh battery pack stores more energy, and that can often result in more range.
Plug-in hybrids and conventional hybrids have smaller batteries since they also use a gas engine for power. For example, a Hyundai Tuscon plug-in hybrid (PHEV) has a battery size of 13.8 kWh. A Hyundai Tucson hybrid (HEV) has a battery size of 1.5 kWh.
When charging your EV, you’ll notice that the charger and the vehicle will display the amount of kWh of energy delivered to the vehicle. This is essentially how much electricity, measured in kWh, has been added to your battery at any given time. This is similar to how many gallons or liters of gasoline have been put into your gas tank.
Efficiency
With gas-powered vehicles, fuel efficiency is a measurement of how efficiently the vehicle uses the fuel to travel a certain distance. The EPA measures gasoline vehicle efficiency in miles per gallon (mpg) – how far the vehicle will go on one gallon of gasoline.
For EVs, the EPA measures efficiency in MPGe, or miles per gallon of gasoline-equivalent. It has determined an amount of electrical energy that is equal to the energy in one gallon of gasoline. For example, a Ford F-150 with a V6 turbo engine has an EPA rating of 20 MPG combined city and highway. By comparison, a Ford F-150 Lightning Extended Range battery-electric has an equivalent of 70 MPGe combined city and highway.
You’ll also see EV efficiency measured in kWh per 100miles. This is the amount of electrical energy (kWh) from the battery pack that is used to travel a distance of 100 miles. The F-150 Lightning Extended Range’s 70 MPGe is equivalent to 48kWh/100 mi or 2.1 mi/kWh. For every 100 miles, the F-150 Lightning will use 48kWh of energy from its battery pack, or will travel 2.1 miles for every 1 kWh.
Putting It All Together
In reality, you don’t need to concern yourself too much about the details of each of the terms.
If you’re shopping for an EV, you can compare the power of the electric motor(s) in kW, the battery size in kWh, and charging speed in kW of different models. Using the EPA range will help you understand the efficiency of different EVs in kWh/100 mi, miles/kWh, or MPGe.
When you’re charging your EV at a Level 3 DC fast charging station, use a charger that delivers power that best matches the vehicle’s peak charging rate. For example, the peak DC charging rate of the Chevrolet Bolt is 65 kW. You can use chargers with different amounts of power. However, since the Bolt is capped at 65 kW, you can achieve the same charging speed with a 100-kW charger that you can with a 350-kW charger.
When installing a Level 2 home charger, check the peak AC charging rating of your vehicle to help determine the amperage of the charger you need. For example, a Hyundai Ioniq 5 has an 11-kW (46-A) onboard AC charger. If your home can support it, installing a 48-A (11.5-kW) home charger is ideal to deliver the maximum amount of electricity to the vehicle in the shortest amount of time.
EV technology is relatively new, but it doesn’t have to be confusing or overwhelming. Having a fundamental understanding of electricity, how an EV works, and the most common terms will help you get the most of your EV experience.
