U.S. Department of Energy – Energy Efficiency and Renewable Energy
Alternative Fuels and Advanced Vehicles Data Center
Charging Equipment for Plug-in Hybrid and All-Electric Vehicles
Charging equipment for PEVs and plug-in hybrids is classified by the amount of power in kilowatts (kW) provided to the battery. Charging times will vary based on how empty the battery is, how much energy the battery can hold, and the type of battery. And the charging time can range from 30 minutes to 20 hours or more, depending on the type of charging equipment used.
Level 1 equipment uses what is considered “standard” electrical-outlet voltage, charging through a 110/120 volt (V), alternating-current (AC) plug and usually requires a dedicated circuit. Level 1 EVSE (Electric Vehicle Service Equipments) is portable and does not require permanent installation of the charging equipment but does need a dedicated line and/or circuit panel. On one end of the cord is a regular, three-prong household plug. On the other end is a connector, which plugs into the vehicle.
Level 1 works well for charging at home, work or when there is only a 120 V outlet available. Based on the battery type, Level 1 charging can take up to 20 hours to reach a full charge, adding about 5 to 6 miles of range per hour of charging time, depending on the vehicle.
Level 2 equipment offers charging through a 240 volt AC plug and requires installation of special charging equipment. This charging option varies up to 80 amperes and 19.2 kW. However, most residential level 2 EVSE will operate at lower power. Many such units operate at 30 amperes, delivering 7.2 kW of power. These units require a dedicated 40 amp circuit.
Most homes have 240 V service available, and because Level 2 EVSE can easily charge a typical EV battery overnight, this will be a common installation for homes.
Level 2 equipment also uses the same connector the vehicle as Level 1 equipment. Based on the battery type and circuit capacity, Level 2 charging can take 3 to 8 hours to reach a full charge, adding about 25 miles of range per hour of charging time, depending on the vehicle.
Level 3 charging will be an even faster AC charging option, though Level 3 equipment is still in development. This charging option will operate at a higher voltage and current than Level 2, and it would be installed at public charging stations. Level 3 charging could take less than 30 minutes to reach a full charge.
Level 3 or DC Fast Charging
Direct-current (DC) fast charging equipment (480 V) provides 50 kW to the battery enabling this type of fast charge to fully charge a battery in less than 30 minutes. This option will likely be used for charging along heavy traffic corridors and at public stations.
All-electric vehicles from the early 1990s, such as the Toyota RAV4 EV and the Chevy S10 EV, were charged by inductive charging techniques which are still being used in some areas. Inductive charging options may be developed for future electric drive vehicles.
Connectors and Plugs
Today’s charging equipment and PEVs use a standard connector and plug receptacle. This connector is based on the Society of Automotive Engineers (SAE) J1772 standard. Any vehicle with this plug receptacle can use any Level 1 or Level 2 charging system. All major vehicle and charging system manufacturers support this standard, which should eliminate drivers’ concerns about whether their vehicle is compatible with the infrastructure.
The only charging connector that has not been standardized yet is the DC fast charging. To receive DC fast charging, most PEVs and PHEVs are using the Tokyo Electric Power Company (TEPCO) connector and receptacle now marketed under the name CHAdeMO. So manufacturers may continue to offer the TEPCO DC fast charge receptacle as an option on vehicles until a standard is develop.
ADAPTED FROM: US Department of Energy