recharging point

A charging station, also known as a charge point or electric vehicle supply equipment (EVSE), is a piece of equipment that supplies electrical power for charging plug-in electric vehicles (including electric cars, electric trucks, electric buses, neighborhood electric vehicles, and plug-in hybrids).

There are two main types: AC charging stations and DC charging stations. Batteries can only be charged with direct current (DC) electric power, while most electricity is delivered from the power grid as alternating current (AC). For this reason, most electric vehicles have a built-in AC-to-DC converter, commonly known as the "onboard charger". At an AC charging station, AC power from the grid is supplied to this onboard charger, which produces DC power to charge the battery. DC chargers facilitate higher power charging (which requires much larger AC-to-DC converters) by building the converter into the charging station instead of the vehicle to avoid size and weight restrictions. The station then supplies DC power to the vehicle directly, bypassing the onboard converter. Most fully electric car models can accept both AC and DC power.

Charging stations provide connectors that conform to a variety of international standards. DC charging stations are commonly equipped with multiple connectors to be able to charge a wide variety of vehicles that utilize competing standards.

Public charging stations are typically found street-side or at retail shopping centers, government facilities, and other parking areas. Private charging stations are typically found at residences, workplaces, and hotels.

Standards

Multiple standards have been established for charging technology to enable interoperability across vendors. Standards are available for nomenclature, power, and connectors. Notably, Tesla has developed proprietary technology in these areas, and built its charging networking starting in 2012.

Nomenclature

In 2011, the European Automobile Manufacturers Association (ACEA) defined the following terms:
* Socket outlet: the port on the electric vehicle supply equipment (EVSE) that supplies charging power to the vehicle
* Plug: the end of the flexible cable that interfaces with the socket outlet on the EVSE. In North America, the socket outlet and plug are not used because the cable is permanently attached.
* Cable: a flexible bundle of conductors that connects the EVSE with the electric vehicle
* Connector: the end of the flexible cable that interfaces with the vehicle inlet
* Vehicle inlet: the port on the electric vehicle that receives charging power

The terms "electric vehicle connector" and "electric vehicle inlet" were previously defined in the same way under Article 625 of the United States National Electric Code (NEC) of 1999. NEC-1999 also defined the term "electric vehicle supply equipment" as the entire unit "installed specifically for the purpose of delivering energy from the premises wiring to the electric vehicle", including "conductors ... electric vehicle connectors, attachment plugs, and all other fittings, devices, power outlets, or apparatuses".

Tesla, Inc. uses the term ''charging station'' as the location of a group of chargers, and the term ''connector'' for an individual charger.

Voltage and power

Early standards

The National Electric Transportation Infrastructure Working Council (IWC) was formed in 1991 by the Electric Power Research Institute with members drawn from automotive manufacturers and the electric utilities to define standards in the United States; early work by the IWC led to the definition of three levels of charging in the 1999 National Electric Code (NEC) Handbook.

Under the 1999 NEC, Level 1 charging equipment (as defined in the NEC handbook but not in the code) was connected to the grid through a standard NEMA 5-20R 3-prong electrical outlet with grounding, and a ground-fault circuit interrupter was required within of the plug. The supply circuit required protection at 125% of the maximum rated current; for example, charging equipment rated at 16 amperes ("amps" or "A") continuous current required a breaker sized to 20 A.

Level 2 charging equipment (as defined in the handbook) was permanently wired and fastened at a fixed location under NEC-1999. It also required grounding and ground-fault protection; in addition, it required an interlock to prevent vehicle startup during charging and a safety breakaway for the cable and connector. A 40 A breaker (125% of continuous maximum supply current) was required to protect the branch circuit. For convenience and speedier charging, many early EVs preferred that owners and operators install Level 2 charging equipment, which was connected to the EV either through an inductive paddle ( Magne Charge) or a conductive connector (Avcon).

Level 3 charging equipment used an off-vehicle rectifier to convert the input AC power to DC, which was then supplied to the vehicle. At the time it was written, the 1999 NEC handbook anticipated that Level 3 charging equipment would require utilities to upgrade their distribution systems and transformers.

SAE

The Society of Automotive Engineers (SAE International) defines the general physical, electrical, communication, and performance requirements for EV charging systems used in North America, as part of standard SAE J1772, initially developed in 2001. SAE J1772 defines four levels of charging, two levels each for AC and DC supplies; the differences between levels are based upon the power distribution type, standards and maximum power.

= Alternating current (AC)

=
AC charging stations connect the vehicle's onboard charging circuitry directly to the AC supply.

* AC Level 1: Connects directly to a standard 120V North American outlet; capable of supplying 616A (0.71.92kilowatts or "kW") depending on the capacity of a dedicated circuit.
* AC Level 2: Utilizes 240V (single phase) or 208V (three phase) power to supply between 6 and 80A (1.419.2kW). It provides a significant charging speed increase over AC Level 1 charging.

= Direct current (DC)

=
Commonly, though incorrectly, called "Level 3" charging based on the older NEC-1999 definition, DC charging is categorized separately in the SAE standard. In DC fast-charging, grid AC power is passed through an AC-to-DC converter in the station before reaching the vehicle's battery, bypassing any AC-to-DC converter onboard the vehicle.

* DC Level 1: Supplies a maximum of 80kW at 501000V.
* DC Level 2: Supplies a maximum of 400kW at 501000V.

Additional standards released by SAE for charging include SAE J3068 (three-phase AC charging, using the Type 2 connector defined in IEC 62196-2) and SAE J3105 (automated connection of DC charging devices).

IEC

In 2003, the International Electrotechnical Commission (IEC) adopted a majority of the SAE J1772 standard under IEC 62196-1 for international implementation.

The IEC alternatively defines charging in ''modes'' (IEC 61851-1):
* ''Mode 1'': slow charging from a regular electrical socket (single- or three-phase AC)
* ''Mode 2'': slow charging from a regular AC socket but with some EV-specific protection arrangement (i.e. the Park & Charge or the PARVE systems)
* ''Mode 3'': slow or fast AC charging using a specific EV multi-pin socket with control and protection functions (i.e. SAE J1772 and IEC 62196-2)
* ''Mode 4'': DC fast charging using a specific charging interface (i.e. IEC 62196-3, such as CHAdeMO)

The connection between the electric grid and "charger" (electric vehicle supply equipment) is defined by three cases (IEC 61851-1):

* ''Case A:'' any charger connected to the mains (the mains supply cable is usually attached to the charger) usually associated with modes 1 or 2.
* ''Case B:'' an on-board vehicle charger with a mains supply cable that can be detached from both the supply and the vehicle – usually mode 3.
* ''Case C:'' DC dedicated charging station. The mains supply cable may be permanently attached to the charge station as in mode 4.

Tesla NACS

The North American Charging Standard was developed by Tesla, Inc. for use in the company's vehicles, it remained a proprietary standard until 2022 when its specifications were published by Tesla. The connector is physically smaller than the J1172/CCS connector, and uses the same pins for both AC and DC charging functionality. Aptera Motors has also adopted the connector standard in its vehicles.

To meet European Union (EU) requirements on recharging points, Tesla vehicles sold in the EU are equipped with an CCS Combo 2 port. Both the North America and the EU port take 480V DC fast charging through Tesla's network of Superchargers, which variously use NACS and CCS charging connectors. Depending on the Supercharger version, power is supplied at 72, 150, or 250 kW, the first corresponding to DC Level 1 and the second and third corresponding to DC Level 2 of SAE J1772. As of Q4 2021, Tesla reported 3,476 supercharging locations worldwide and 31,498 supercharging chargers (about 9 chargers per location on average).

Future development

An extension to the CCS DC fast-charging standard for electric cars and light trucks is under development, which will provide higher power charging for large commercial vehicles ( Class 8, and possibly 6 and 7 as well, including school and transit buses). When the Charging Interface Initiative e. V. (CharIN) task force was formed in March 2018, the new standard being developed was originally called High Power Charging (HPC) for Commercial Vehicles (HPCCV), later renamed Megawatt Charging System (MCS). MCS is expected to operate in the range of 2001500V and 03000A for a theoretical maximum power of 4.5megawatts (MW). The proposal calls for MCS charge ports to be compatible with existing CCS and HPC chargers. The task force released aggregated requirements in February 2019, which called for maximum limits of 1000V DC (optionally, 1500V DC) and 3000A continuous rating.

A connector design was selected in May 2019 and tested at the National Renewable Energy Laboratory (NREL) in September 2020. Thirteen manufacturers participated in the test, which checked the coupling and thermal performance of seven vehicle inlets and eleven charger connectors. The final connector requirements and specification was adopted in December 2021 as MCS connector version 3.2.

With support from Portland General Electric, on 21 April 2021 Daimler Trucks North America opened the "Electric Island", the first heavy-duty vehicle charging station, across the street from its headquarters in Portland, Oregon. The station is capable of charging eight vehicles simultaneously, and the charging bays are sized to accommodate tractor-trailers. In addition, the design is capable of accommodating >1MW chargers once they are available. A startup company, WattEV, announced plans in May 2021 to build a 40-stall truck stop/charging station in Bakersfield, California; at full capacity, it would provide a combined 25MW of charging power, partially drawn from an on-site solar array and battery storage.

Connectors

Common connectors include Type 1 (Yazaki), Type 2 (Mennekes), Type 3 (Scame), CCS Combo 1 and 2, CHAdeMO, and Tesla. Many standard plug types are defined in IEC 62196-2 (for AC supplied power) and 62196-3 (for DC supplied power):

* Type 1: single-phase AC vehicle coupler – SAE J1772/2009 automotive plug specifications
* Type 2: single- and three-phase AC vehicle coupler – VDE-AR-E 2623-2-2, SAE J3068, and GB/T 20234.2 plug specifications
* Type 3: single- and three-phase AC vehicle coupler equipped with safety shutters – EV Plug Alliance proposal
* Type 4: DC fast charge couplers
** Configuration AA: CHAdeMO
** Configuration BB: GB/T 20234.3
** Configurations CC/DD: (reserved)
** Configuration EE: CCS Combo 1
** Configuration FF: CCS Combo 2

; Notes

CCS DC charging requires Powerline Communications (PLC). Two connectors are added at the bottom of Type 1 or Type 2 vehicle inlets and charging plugs to supply DC current. These are commonly known as Combo 1 or Combo 2 connectors. The choice of style inlets is normally standardized on a per-country basis so that public chargers do not need to fit cables with both variants. Generally, North America uses Combo 1 style vehicle inlets, while most of the rest of the world uses Combo 2.

The CHAdeMO standard is favored by Nissan, Mitsubishi, and Toyota, while the SAE J1772 Combo standard is backed by GM, Ford, Volkswagen, BMW, and Hyundai. Both systems charge to 80% in approximately 20 minutes, but the two systems are completely incompatible. Richard Martin, editorial director for clean technology marketing and consultant firm Navigant Research, stated:

The broader conflict between the CHAdeMO and SAE Combo connectors, we see that as a hindrance to the market over the next several years that needs to be worked out.

Historical connectors

In the United States, many of the EVs first marketed in the late 1990s and early 2000s such as the GM EV1, Ford Ranger EV, and Chevrolet S-10 EV preferred the use of Level 2 (single-phase AC) EVSE, as defined under NEC-1999, to maintain acceptable charging speed. These EVSEs were fitted with either an inductive connector (Magne Charge) or a conductive connector (generally AVCON). Proponents of the inductive system were GM, Nissan, and Toyota; DaimlerChrysler, Ford, and Honda backed the conductive system.

Magne Charge paddles were available in two different sizes: an older, larger paddle (used for the EV1 and S-10 EV) and a newer, smaller paddle (used for the first-generation Toyota RAV4 EV, but backwards compatible with large-paddle vehicles through an adapter). The larger paddle (introduced in 1994) was required to accommodate a liquid-cooled vehicle inlet charge port; the smaller paddle (introduced in 2000) interfaced with an air-cooled inlet instead. SAE J1773, which described the technical requirements for inductive paddle coupling, was first issued in January 1995, with another revision issued in November 1999.

The influential California Air Resources Board adopted the conductive connector as its standard on 28 June 2001, based on lower costs and durability, and the Magne Charge paddle was discontinued by the following March. Three conductive connectors existed at the time, named according to their manufacturers: Avcon (aka butt-and-pin, used by Ford, Solectria, and Honda); Yazaki (aka pin-and-sleeve, on the RAV4 EV); and ODU (used by DaimlerChrysler). The Avcon butt-and-pin connector supported Level 2 and Level 3 (DC) charging and was described in the appendix of the first version (1996) of the SAE J1772 recommended practice; the 2001 version moved the connector description into the body of the practice, making it the de facto standard for the United States.  IWC recommended the Avcon butt connector for North America, based on environmental and durability testing. As implemented, the Avcon connector used four contacts for Level 2 (L1, L2, Pilot, Ground) and added five more (three for serial communications, and two for DC power) for Level 3 (L1, L2, Pilot, Com1, Com2, Ground, Clean Data ground, DC+, DC-). By 2009, J1772 had instead adopted the round pin-and-sleeve (Yazaki) connector as its standard implementation, and the rectangular Avcon butt connector was rendered obsolete.

Charging time

File:2014 BYD E6.jpg, BYD e6. Able to recharge the battery in 15 minutes to 80%
File:BSVAG Solaris Urbino 12 electric "EMIL" Hauptbahnhof.jpg, Solaris Urbino 12 electric, battery electric bus, inductive charging station

Charging time basically depends on the battery's capacity, power density, and charging power. The larger the capacity, the more charge the battery can hold (analogous to the size of a fuel tank). Higher power density allows the battery to accept more charge/unit time (the size of the tank opening). Higher charging power supplies more energy per unit time (analogous to a pump's flow rate). An important downside of charging at fast speeds is that it also stresses the mains electricity grid more.

California Air Resources Board specified a target minimum range of 150 miles to qualify as a zero-emission vehicle, and further specified that the vehicle should allow for fast-charging.

Charge time can be calculated as:

$\text = \frac$

The effective charging power can be lower than the maximum charging power due to limitations of the battery or battery management system, charging losses (which can be as high as 25%), and vary over time due to charging limits applied by a charge controller.

Battery capacity

The usable battery capacity of a first-generation electric vehicle, such as the original Nissan Leaf, was about 20kilowatt-hours (kWh), giving it a range of about . Tesla was the first company to introduce longer-range vehicles, initially releasing their Model S with battery capacities of 40kWh, 60kWh and 85kWh, with the latter lasting for about . Current plug-in hybrid vehicles typically have an electric range of 15 to 60 miles.

AC to DC conversion

Batteries are charged with DC power. To charge from the AC power supplied by the electrical grid, EVs have a small AC-to-DC converter built into the vehicle. The charging cable supplies AC power directly from the grid, and the vehicle converts this power to DC internally and charges its battery. The built-in converters on most EVs typically support charging speeds up to 6–7kW, sufficient for overnight charging. This is known as "AC charging". To facilitate rapid recharging of EVs, much higher power (50–100+kW) is necessary. This requires a much larger AC-to-DC converter which is not practical to integrate into the vehicle. Instead, the AC-to-DC conversion is performed by the charging station, and DC power is supplied to the vehicle directly, bypassing the built-in converter. This is known as DC fast charging.

Safety

File:ShanghaiExpo2010 Shuttle Bus.jpg, A Sunwin electric bus in Shanghai at a charging station
File:TOSA Aeroport rail avec tête.JPG, A battery electric bus charging station in Geneva, Switzerland

Charging stations are usually accessible to multiple electric vehicles and are equipped with current or connection sensing mechanisms to disconnect the power when the EV is not charging.

The two main types of safety sensors:

* Current sensors monitor power consumed, and maintain the connection only while demand is within a predetermined range.
* Sensor wires provide a feedback