Charging Basics

Although charging an electric car is a bit different from refueling a conventional vehicle, choosing to drive an electric car does not require a substantial change in lifestyle. That means you can commute, go to the grocery store, and travel just like you always have, while dramatically reducing your carbon emissions. Here’s what you need to know about range and charging speed.


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Range And Charging Speed

There are five things you should know about range and charging: three that impact how far you can go in your electric vehicle (EV) and two that impact how quickly you can charge.

What impacts how far I can go?

  • The battery: EV battery size is measured in kilowatt-hours (kWh). The more kWh capacity your car’s battery has, the farther you can go between charges.
  • The efficiency: Different EV models drive a different number of miles for every kWh of battery capacity. The vehicle’s battery size and efficiency together determine its range, along with driving conditions.
  • The weather: The temperature and weather conditions will impact your EV's range (the colder it gets, the shorter the range), but EVs can handle whatever a New England winter can throw at them. The EPA's rating on miles per charge is a good number for a year-round basis. Most of the year, you will get more than the rating. Learn more on our Winter Driving page

What impacts how fast I can charge?

  • The onboard charger: Your car has an onboard device to manage a safe charging speed. Its capacity, measured in kilowatts (kW), affects your charging speed. The more kW, the faster the charge!
  • The charging level: There are three speeds of EV charging depending on where you plug into. In increasing level of speed, they are: Level 1, Level 2, and DC Fast Charging.

Charging Levels

There are three levels of charging available for EVs today: Level I, Level II, and DC Fast Charging. Some EVs use one plug to charge a Levels I and II, and a second plug to charge at Level III or DC fast charging.  Cars with the North American Charging Standard (NACS) port, use one port for all three levels of charging. 

The NACS charging port was originally used only for Tesla cars.  Tesla opened NACS for use by other manufacturers in 2022. Many manufacturers have announced that in 2025, their vehicles will come standard with a NACS port and in 2024 existing cars will gain access to a converter to start using the Tesla charging network.  

Level I

Level I charging simply requires a 120 volt outlet. All electric vehicles come equipped with a cord that you can plug into a common outlet. A Level I charge uses the J1772 or NACS charging ports and will typically add 4 miles of range for every hour spent charging.

Level II

Level II charging requires a 240 volt outlet and a charging unit. You can purchase a Level II unit online and install it in your home with the help of a licensed electrician. There are also many publicly available Level II units. A Level II charge uses the J1772 or NACS charging ports and has the potential to add 11 to 54 miles of range for every hour spent charging (the actual speed depends upon the capacity of the charger built into your EV).

DC Fast Charging

DC (Direct Current) Fast Charging is the fastest charging available for passenger cars. It is increasingly available along major highways and intended for longer trips. Currently, many manufacturers use the J1772 combo (otherwise known as CCS DCFC or SAE Combo), few manufacturers use the CHAdeMO (but this technology is being phased out in North America), and Tesla (and other manufacturers starting in 2025) use the North American Charging Standard (NACS) port. Not all DC Fast Charging stations will have plugs for each type of charging port. As a result, you must make sure the DC Fast Charging station you visit has the correct plug to match up with the charging port on your vehicle or that you have the correct converter.

Here's a summary of the important things to know about each charging level.

 Level ILevel IIDC Fast Charging
Voltage120240208/480 three-phase input
Charging speed~4 miles/hr~11-54 miles/hr*45-200miles/30 min*
Charging portJ1772 or NACSJ1772 or NACSJ1772 combo (also known as CCS DCFC or SAE Combo), CHAdeMO or NACS
Can I install one in my home?You don’t need to! Just use a normal 120 volt outlet and the charging cord that comes with your EV.Yes (may require adding a 240 volt line if your home does not already have one)No
Are there units publicly available?Yes (See Charging on the go.)Yes (See Charging on the go.)Yes (See Charging on the go.)
Is an additional charging port required on the vehicle?No**No**Yes** (standard on some vehicles, additional package on others )

*Level 2 charging speed largely depends on the vehicle model. Most all-electric cars will charge at 22+ miles/hr, while a plug-in hybrids will only add 12-15 miles/hr.

**Cars using NACS are able to use converters to access stations with J1772/J1772 Combo. Cars that use J1772/J1772 Combo whose manufacturers have an agreement with Tesla can use a converter to access the Tesla Charging Network from 2024 onwards.

DC Fast Charging Basics

Most EV drivers charge at Level I and Level II because it’s inexpensive, convenient, and readily available. Although Level II charging speeds may be different from car model to car model (ie, a Tesla vs a Nissan LEAF), the speed you’ll charge at is consistent over time. For example, a Hyundai Kona charging at Level II will add roughly 30 miles of range per hour spent charging whether you plug in at 50% charged or 80% charged. Similar vehicles, like the Chevrolet Bolt, Polestar 2, and the VW ID.4, have similar Level II charging speeds as the Kona.

However, with DC fast charging, there’s a lot more variability across different car models, charging stations, and even according to how much juice you have left when you plug in.

Here’s a generalized “cheat sheet” to help decode how quickly you can expect to charge with different models and charging stations. Cold weather will slow down charging speeds across the board.

Fast charging power Estimated miles gained in 30 minutes of charging  Cars 
50 kW ~90 miles Chevrolet Bolt, Nissan LEAF, Volkswagen e-Golf, Hyundai Ioniq EV
77 kW ~150 miles Kia Niro EV, Hyundai Kona EV 
100 kW ~166 miles Nissan LEAF Plus, Audi e-Tron, Jaguar I-Pace 
150 kW ~200 miles Tesla models compatible with V2 Superchargers 

The key thing to remember about DC fast charging is that it’s fastest between 10% and 80% state of charge. Fast charging slows down to “Level II” speeds once you hit 80% capacity. Below, we’ve visualized a sample charging session for a Chevy Bolt.

DC charging rates

The first hour of charging (assuming you plug in when the car reads 10% or less) happens at the car’s maximum DC fast charging speed. Once the vehicle is charged to nearly 80%, fast charging slows down and it may take much longer to top off the last 50 miles than the previous 180 miles. That’s why you might see automakers advertise their EVs’ fast charging speeds as “time to 80% charged.” Two important conclusions about DC fast charging that are important for EV drivers to know:

  1. There is a lot of variability in speed of DC fast charging depending on the weather, the station you’re plugged into, and the vehicle model itself.
  2. Charging to 100% using a DC fast charger may not be the best way to fuel an EV for a long trip. Tools like A Better Route Planner can help you optimize long-distance travel stops to minimize the time you spend waiting.

Charging equipment

The charger: The charger is built into the electric vehicle. The charging port accepts electricity from an outside source and stores it in the vehicle's battery. There are different types of charging ports, which becomes very important when we talk about DC Fast Charging. Here are four of the more common options:


J1772 charge port

Built into all non-North American Charging Standard (NACS) electric vehicles, suitable for Level I or Level II charging. All EVs come with a cord that plugs into the J1772 port in the vehicle on one end and a 120-volt outlet on the other end.

J1772 combo

J1772 combo or CCS

Built into all-electric EVs for DC Fast Charging. The J1772 combo is also known as the CCS DCFC or SAE Combo. Cars with the J1772 combo port can plug in Level I, Level II, and fast charging cables into this one port. 



Built into some EVs, like the Nissan LEAF and Mitsubishi Outlander PHEV, for DC Fast Charging. That means these EVs have two separate ports: J1772 for Level I & II and CHAdeMO for DC Fast Charging. CHAdeMO users may have difficulty finding fast chargers as CHAdeMO is being phased out in the US. There are currently no adapters that would allow a vehicle with CHAdeMO port to charge using a different plug, such as J1772 Combo or NACS.


North American Charging Standard  (NACS)

North American Charging Standard (NACS)

This port was previously called the Tesla connector and only used by Tesla cars, but North American Charging Standard is the official name. In 2022, Tesla opened their Tesla charging connector and port to the world in a bid to encourage a North American charging standard.  As of fall 2023, Tesla has announced partnerships with Ford, GM (Chevrolet, GMC, and Cadillac), Aptera, Rivian, Polestar, Mercedes-Benz, Nissan, BMW, Hyundai, Kia, Jaguar, and Honda where these manufacturers will install NACS on their vehicles and their vehicles will be allowed to use Tesla's Super Charger Network. This means that current customers of the aforementioned manufacturers will be able to use NACS adapters in spring 2024 to access Tesla's Super Charger Network and, in 2025, all new cars produced by these manufacturers will come standard with a NACS port installed for charging.  

Electric Vehicle Supply Equipment (EVSE)

The EVSE is the machine with the cord that you plug into your onboard charger. The plug on the EVSE must match up with the charging port on the vehicle. All vehicles come equipped with a cord that will plug into a normal wall outlet for a "trickle charge". More on this below!

EVSE Collage
You can install EVSE or a Level II charging unit in your garage and plug in as soon as you get home. You can also install EVSE on an exterior wall to charge outside. Note you do not need EVSE to plug-in for Level I charging.

Everything You Need To Know About EV Charging

Most EV drivers charge at home

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