What Factors Affect Electric Vehicle Charging Speed?

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Charging an electric vehicle (EV) is a major part of EV ownership and can take anywhere from 30 minutes to more than 40 hours. There are several factors that can impact how long it takes to fully charge your EV. Here are some of the most common factors affecting your EV charge time.

• The level of charger you are using
• Your EV battery’s size and fullness
• If it’s cold in your area
• Your EV’s maximum charge rate
• If you are using other functions in your EV while charging
• Your battery’s age or deterioration level

The level of charger

There are three levels of EV chargers — Level 1, Level 2, and Level 3. Level 1 chargers are the slowest charging option and can take more than 40 hours to fully charge an EV. Meanwhile, Level 3 chargers — also known as DC fast chargers — can provide a full charge in as little as 30 minutes. If you are charging your EV at home, you will use either a Level 1 or Level 2 charger. If you are charging at a public charging station, you may be able to use a Level 3 charger. The level of charger you use will have a significant impact on how long it takes to fully charge your EV.

EV battery size and fullness

Some EV batteries are larger than others. The average EV battery size is around 66.5 kilowatt-hours (kWh), although some EVs on the market have a battery larger than 100 kWh. The larger your EV battery is, the longer it will take to receive a full charge. Similarly, if your battery is nearly empty, it will take longer to charge than if it is half-full. 

The temperature in your area

Cold temperatures can affect how quickly an EV battery charges. During the colder months, your EV may take longer to charge than when the temperature is warmer. A study by the Idaho National Laboratory found that EV batteries took in 36% less energy in 32 degrees Fahrenheit than they did in the same amount of time in 77 degrees. The colder it is, the more time it takes to charge an EV.

Your EV’s maximum charging rate

Your EV has a set maximum charge rate (also called a voltage limit) that determines how much energy it can take in, regardless of the level of power a charger can provide. For example, if your EV’s maximum charging rate is 7 kW and you use a charger that can send up to 22 kW of electricity, your EV will still only charge at the rate of 7 kW.

The inverse is true, too. If your EV can accept up to 15 kW but you’re using a charger that has a maximum output of 7 kW, the vehicle will charge at a 7-kW rate.

If other EV functions are in use

If you use a public charging station, you may sit in your car while it charges. Using the radio, heating, air conditioning, lights, or other accessories while the vehicle is charging can extend the charge time. This is because some of the battery’s charge will instead power the other features in use.

Battery deterioration

Over time, an EV battery can deteriorate, and its charging capacity will lower. EV batteries will come with a warranty guaranteeing a certain amount of time before you will experience battery deterioration. There is a government mandate requiring EV manufacturers warranty batteries for up to eight years or 100,000 miles. If you notice signs of deterioration before then, contact the manufacturer.