Developing Infrastructure to Charge Plug-In Electric Vehicles
AC Level 1 Charging
2 to 5 miles of range per
1 hour of charging
J1772 charge port
AC Level 1 equipment (often referred to simply as Level 1) provides charging through a 120 volt (V) AC plug. Most, if not all, plug-in electric vehicles (PEVs) will come with an AC 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. The SAE J1772 connector plugs in to the car’s J1772 charge port, and the NEMA connector plugs in to a standard NEMA wall outlet.
AC Level 1 is typically used for charging when there is only a 120V outlet available 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.
AC 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 AC Level 2 equipment can charge a typical EV battery overnight, it will commonly be installed at EV owners' homes for home charging. Level 2 equipment is also commonly used for public charging. This charging option can operate at up to 80 amperes and 19.2 kW. However, most residential AC Level 2 equipment operates at lower power. Many of these units operate at up to 30 amperes, delivering 7.2 kW of power. These units require a dedicated 40-amp circuit.
AC Level 2 equipment uses the same SAE J1772 connector and charge port that Level 1 equipment uses. All commercially available PEVs have the ability to charge using AC Level 1 and AC 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
Direct-current (DC) fast charging equipment, sometimes called DC Level 2 (typically 208/480V AC three-phase input), enables rapid charging along heavy traffic corridors at installed stations. There are three types of DC fast charging systems, depending on the type of charge port on the vehicle: a J1772 combo, CHAdeMO, or Tesla.
The J1772 combo (also known as the combined charging system or CCS) connector is used by Chevrolet and BMW and 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 CHAdeMO connector is the most common of the three connector types and is used by Nissan, Mitsubishi, and Toyota.
Tesla vehicles have a unique charge port and connector that works for all their charging options including their fast charging option, called a supercharger.
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 U.S., 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 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. See this report prepared by researchers at Idaho National Laboratory, Argonne National Laboratory, and the National Renewable Energy Laboratory, which 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 recently introduced commercially for installation as an aftermarket add-on. Currently available wireless charging stations operate at power levels comparable to AC Level 2, though this technology has been used in other countries at higher power levels for mass transit operations.