Because we have always used gas cars, we all have a basic understanding of how they work. However, as we switch to electric vehicles, there are some concepts and words that we should become familiar with. I will do my best to introduce them to you in an easy-to-understand manner, with the fewest technical terms.
Driving an electric vehicle (EV) is easier than driving a gasoline-powered car. Instead of starting it, you simply turn it on. Unlike a gas car, an EV doesn’t make any noise to indicate that it’s on. However, it does have a normal gear selector with Park, Reverse, Neutral, and Drive. When you come to a stop, an EV is silent because it doesn’t have an engine. As a result, there is almost no noise when you accelerate. It feels strange at first, but you quickly become accustomed to it.
Soon, you will have to charge it. The charge port is like a gas filler and has a door. The first thing you should learn about your EV is out how to open the charge door and get to the charge port.
Save this page.
We’ll start with the basics and then go into more technical details as you read further.
Electrical terms EV owners will need to understand.
Watt (W) Kilowatt (kW) Megawatt (MW) Gigawatt (GW)
- The Watt is a common unit of measure for energy. Light bulbs come in 5W – 200W sizes.
- A Kilowatt is a thousand watts.
- A regular appliance outlet in your home can supply up to 1,500 watts, which equals 1.5 kilowatts. Charging an EV for 8 hours using this outlet can add approximately 40 miles of range to your battery.
- Larger appliances such as an electric range, oven, water heater, or clothes dryer use a stronger power outlet called a “NEMA 14-50” or 220 volt outlet. This outlet can provide 9.6 kW of power. Charging an EV for 8 hours using this outlet can add approximately 300 miles of range to your battery.
- A 100 kW electric motor = 134 horsepower.
- The average EV will go 3.5-4.5 miles per kWh.
- A Megawatt is a thousand kilowatts, or a million watts.
- A Gigawatt is a thousand Megawatts, or a billion watts.
Charging Math
When you charge your car, you add kilowatt hours to the battery. As you drive, you use up these kilowatt hours. The larger the capacity of your battery, the longer you can travel before needing to recharge. However, having a larger battery also increases the cost of the car.
EV batteries are measured by how much energy they can hold, which is expressed in kilowatt hours (kWh). In an electric vehicle, the efficiency is measured in “miles per kWh,” which can be compared to “miles per gallon” in a conventional car.
Understanding Charge Time and Range
Typical electric vehicles have battery packs that can store anywhere from 20 to 80 kWh of energy, Each kWh moves the car approximately 3.5 to 4.0 miles. Like gas cars, if you accelerate hard and drive fast, you get less mileage. An EV with a 20 kWh battery can travel up to 80 miles, while one with an 80 kWh battery can travel up to 320 miles.
- 1) Multiply the electrical outlet kW times the hours connected. The result is kWh.
- 2) Multiply the result (kWh) by 3.5 or 4.0 (= EV miles per kwh).
- Examples:
- Almost all houses have a 240v outlet called a “NEMA 14-50”. It powers an electric stove or clothes dryer. It delivers 9.6 kW.
- Eight hours charge time X 9.6 kW = 76.8 kWh
- 76.8 kWh X 4 miles per kWh = 307 miles.
- An appliance outlet is 1.5 kW.
- Eight hours charge time X 1.5 kW = 12 kWh
- 12 kWh X 4 miles per kWh = 48 miles.
- Almost all houses have a 240v outlet called a “NEMA 14-50”. It powers an electric stove or clothes dryer. It delivers 9.6 kW.
Watt hour (Wh) Kilowatt hour (kWh) Megawatt hour (MWh) Gigawatt hour (GWh)
The letter “h” stands for hour and is used to measure the amount of electricity used in a certain number of hours. For instance, if you use a 1 kW appliance for 2 hours, you will have consumed 2 kilowatt-hours (kWh). Your monthly electricity bill is calculated based on the total number of kilowatt-hours you used in the previous month. According to the U.S. Energy Information Administration, the average home consumes 886 kWh of electricity per month.
The price per kilowatt-hour (kWh) varies across the country, ranging from 11 cents to 80 cents, with the national average being 11.8 cents. To determine the cost, you multiply the price per kilowatt-hour by the number of kilowatt-hours used. For example, if the price is 11 cents per kWh and you used 886 kWh, the calculation would be $98. Alternatively, if the price is 80 cents per kWh and you consumed 886 kWh, the cost would be $709.
Amps, Amperes, Amperage, and Safety
Amps are a measure of how strong an electrical current is. Think of it as similar to air or water pressure. Wires and cables, like extension cords, have a rating in amps. Wires with higher amperage can handle more electrical strength.
A regular appliance outlet is rated at 15 amps. This is called Level 1 charging.
A common high power outlet, the NEMA 14-50, is rated at 50 amps, and is called level 2 charging.
The NEMA 14-50 is the same outlet used for electric stoves and clothes dryers.
All EVs can be charged from these outlets.
Drawing too much electricity through a wire can make it get too hot and cause fires. Fuses and circuit breakers are measured in electricity units called amps. If there is too much electricity going through a wire, the fuse “blows” to protect the circuit and stop the wire from getting too hot and causing a fire. The National Fire Protection Agency says that more than 50,000 fires in people’s homes are caused by electricity each year, and these fires result in 500 deaths. Statistics show that for all car fires, 98% are gas cars, and 0.5% are EVs.
Energy and Power
Energy and Power are words that are used everywhere, and are not just for talking about electricity. Here are some simple terms that will help you understand our energy future better.
What is the difference between energy and power?
Energy is the stored capacity to do tasks. Energy is stored in your electric vehicle (EV) battery.
Power is the act of performing tasks. The motor converts energy into power to move the car.
Understanding electricity by imagining it as water.