Electricity can be used to power all-electric vehicles and plug-in hybrid electric vehicles directly from the power grid. Vehicles that run on electricity produce no tailpipe emissions. The only emissions that can be attributed to electricity are those generated in the production process at the power plant. Electricity is easily accessible for short-range driving.
Charging equipment for plug-in hybrid electric vehicles (PHEVs) and all-electric vehicles (EVs) is classified by the maximum amount of power in kilowatts (kW) provided to the battery. Charging times vary based on how depleted the battery is, how much energy it holds, the type of battery, and the type of EVSE. The charging time can range from 30 minutes to 20 hours or more, depending on the type of charging equipment used.
Level 1 equipment provides charging through a 120 volt (V), alternating-current (AC) plug (up to 15 amperes and 1.8 kW). Level 1 EVSE is portable and does not require installation of charging equipment. On one end of the cord is a standard, 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, or "trickle charge," available. Depending on the battery type, Level 1 charging can take 6 to 20 hours for a fully depleted battery to reach a full charge, adding about 2 to 5 miles of range per hour of charging time, depending on the vehicle.
Level 2 equipment offers charging through a 240 V, AC plug and requires installation of home charging or public charging equipment. This charging option can operate at 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 on the vehicle as Level 1 equipment. Based on the battery type and circuit capacity, Level 2 charging can take 3 to 8 hours for a fully depleted battery to reach a full charge, adding about 10 to 20 miles of range per hour of charging time, depending on the vehicle.
Level 3 charging will enable a faster AC charging option. 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.
DC Fast Charging
Direct-current (DC) fast charging equipment (480 V) provides 50 kW to the battery. This option enables charging along heavy traffic corridors and at public stations. A DC fast charge can take less than 30 minutes to fully charge a depleted battery, adding 60 to 80 miles of range to a light-duty PHEV or EV.
Inductive charging equipment installed for all-electric vehicles in the early 1990s, such as the Toyota RAV4 EV and the Chevy S10 EV, is still being used in certain areas. Some companies are working on inductive charging options for future electric drive vehicles.
Connectors and Plugs
Modern charging equipment and vehicles have 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 EVSE. 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 DC fast charging connector has not been standardized yet. To receive DC fast charging, most EVs and PHEVs are using the Tokyo Electric Power Company (TEPCO) connector and receptacle, which have not become standard yet. Manufacturers may offer the TEPCO DC fast charge receptacle as an option on vehicles until a standard is in place.