Developing Infrastructure to Charge Plug-In Electric Vehicles
Level 1 Charging
2 to 5 miles of range per
1 hour of charging
J1772 charge port
Alternating Current (AC) Level 1 equipment (often referred to simply as Level 1) provides charging through a 120 volt (V) AC plug. Most, if not all, PEVs will come with a Level 1 cordset, so no additional charging equipment is required. On one end of the cord is a standard NEMA connector, (for example, a NEMA 5-15, which is a common three-prong household plug) and on the other end is an SAE J1772 standard connector (often referred to simply as J1772, shown in the above image). The J1772 connector plugs in to the car’s J1772 charge port, and the NEMA connector plugs in to a standard NEMA wall outlet.
Level 1 charging is typically used when there is only a 120V outlet available, such as while charging at home, but can easily provide charging for all of a driver's needs. For example, 8 hours of charging at 120V can replenish about 40 miles of electric range for a mid-size PEV. As of 2019, less than 5% of public charging outlets in the United States were Level 1.
Level 2 Charging
10 to 20 miles of range per
1 hour of charging
J1772 charge port
AC Level 2 equipment (often referred to simply as Level 2) offers charging through 240V (typical in residential applications) or 208V (typical in commercial applications) electrical service. Most homes have 240V service available, and because Level 2 equipment can charge a typical PEV battery overnight, it is commonly installed at PEV owners' homes for home charging. Level 2 equipment is also commonly used for public and workplace charging. This charging option can operate at up to 80 amperes (Amp) and 19.2 kW. However, most residential Level 2 equipment operates at lower power. Many of these units operate at up to 30 Amps, delivering 7.2 kW of power. These units require a dedicated 40-Amp circuit. As of 2019, over 80% of public outlets in the United States were Level 2.
Level 2 charging equipment uses the same J1772 connector and charge port that Level 1 equipment uses. All commercially available PEVs have the ability to charge using Level 1 and Level 2 charging equipment. Although Tesla vehicles do not have a J1772 charge port, Tesla does sell an adapter.
DC Fast Charging
60 to 80 miles of range per
20 minutes of charging
CCS charge port
Direct-current (DC) fast charging equipment (typically 208/480V AC three-phase input), enables rapid charging along heavy traffic corridors at installed stations. As of 2019, about 15% of charging outlets in the United States were DC fast chargers. There are three types of DC fast charging systems, depending on the type of charge port on the vehicle: SAE Combined Charging System (CCS), CHAdeMO, or Tesla.
The CCS (also known as J1772 combo) connector is unique because a driver can use the same charge port when charging with Level 1, 2, or DC fast equipment. The only difference is that the DC fast charge connector has two additional bottom pins. The CCS connector is used by Chevorlet and BMW PEVs, for example
The CHAdeMO connector is the most common of the three connector types and is used by Nissan, Mitsubishi, and Toyota PEVs, for example.
Tesla vehicles have a unique charge port and connector that works for all their charging options including their fast charging option, called a supercharger.
Increasing available public and private charging equipment requires infrastructure procurement. Learn about how to successfully plan for, procure, and install charging infrastructure.
Once charging infrastructure has been procured and installed, it must be properly operated and maintained. Learn about charging infrastructure operation and maintenance considerations.
Future AC Charging Options
An additional standard (SAE J3068) is under development for higher rates of AC charging using three-phase power, which is common at commercial and industrial locations in the United States. Some components of the standard will be adapted from the European three-phase charging standards and specified for North American AC grid voltages and requirements. In the United States, the common three-phase voltages are typically 208/120 V, 480/277 V. The standard will target power levels between 6kW and 130kW. In addition, the U.S. Department of Energy’s (DOE) Vehicle Technologies Office is pursuing research that will bridge the technology gaps associated with implementing an extreme fast charging network in the United States. A 2017 report highlights technology gaps at the battery, vehicle, and infrastructure levels.
Inductive charging equipment, which uses an electromagnetic field to transfer electricity to a PEV without a cord, has been introduced commercially for installation as an aftermarket add-on. Most currently available wireless charging stations operate at power levels comparable to Level 2, though this technology is also available at higher power levels for mass transit operations.