SAE J1772

SAE J1772 (IEC 62196 Type 1), also known as a J plug, is a North American standard for electrical connectors for electric vehicles maintained by the SAE International and has the formal title "SAE Surface Vehicle Recommended Practice J1772, SAE Electric Vehicle Conductive Charge Coupler". It covers the general physical, electrical, communication protocol, and performance requirements for the electric vehicle conductive charge system and coupler. The intent is to define a common electric vehicle conductive charging system architecture including operational requirements and the functional and dimensional requirements for the vehicle inlet and mating connector.
History.
The main stimulus for the development of SAE J1772 came from the California Air Resources Board (CARB). Formerly electric vehicles like the General Motors EV1 had used inductive charger couplers. These were ruled out in favor of conductive coupling to supply electricity for recharging with the board settling upon the SAE J1772-2001 standard as the charging interface for electric vehicles in California in June 2001. Avcon manufactured a rectangular connector compliant with specification , capable of delivering up to 6.6 kW of electrical power.)
The CARB regulation of 2001 mandated the usage of SAE J1772-2001 beginning with the 2006 model year. Later requirements asked for higher currents to be used than the Avcon connector could provide. This process led to the proposal of a new round connector design by Yazaki which allows for an increased power delivery of up to 19.2 kW delivered via single phase 120–240 V AC at up to 80 amperes. In 2008 the CARB published a draft amendment to Title 13 section 1962.2 that mandated the usage of the oncoming SAE J1772 standard beginning with the 2010 model year; this was approved in 2012.
The Yazaki plug that was built to the new SAE J1772 plug standard successfully completed certification at UL. The standard specification was subsequently voted upon by the SAE committee in July 2009. On January 14, 2010 the SAE J1772 REV 2009 was adopted by the SAE Motor Vehicle Council. The companies participating in or supporting the revised 2009 standard include smart, Chrysler, GM, Ford, Toyota, Honda, Nissan, and Tesla.
The SAE J1772-2009 connector specification has been added to the international IEC 62196-2 standard (“Part 2: Dimensional compatibility and interchangeability requirements for a.c. pin and contact-tube accessories”) with voting on the final specification to close in May 2011. The SAE J1772 connector is considered a “Type 1” implementation providing a single phase coupler.
Vehicle equipment.
The SAE J1772-2009 was adopted by the car manufacturers of post-2000 electric vehicles like the third generation of the Chevrolet Volt and Nissan Leaf as the early models. The connector became standard equipment in the U.S. market due to the availability of charging stations with that plug type in the nation's electric vehicle network (with the help of funding such as ChargePoint America program drawing grants from provisions of the American Recovery and Reinvestment Act).
The European versions were equipped with a SAE J1772-2009 inlet as well until the automotive industry settled on the IEC Type 2 “Mennekes” connector as the standard inletsince all IEC connectors use the same SAE J1772 signaling protocol the car manufacturers are selling cars with either a SAE J1772-2009 inlet or an IEC Type 2 inlet depending on the market. There are also (passive) adapters available that can convert J1772-2009 to IEC Type 2 and vice versa. The only difference is that most European versions have an on-board charger that can take advantage of three-phase electric power with higher voltage and current limits even for the same basic electric vehicle model (such as Chevrolet Volt / Opel Ampera).
Combined Charging System (CCS).
SAE is developing a Combined Charging System with a "Combo Coupler" variant of the J1772-2009 connector with additional pins (Combo 1) to accommodate fast DC charging at 200–450 volts DC and up to 90 kW. This will also use Power-line communication technology to communicate between the vehicle, off-board charger, and smart grid. Seven car makers (Audi, BMW, Daimler, Ford, General Motors, Hyundai, Porsche, Volvo, and Volkswagen) had agreed to introduce the “Combined Charging System” in mid-2012. The first vehicles using the SAE Combo plug were the BMW i3 released in late 2013, and the Chevrolet Spark EV released in 2014. 
In Europe, the combo coupler is based on the Type 2 (VDE) AC charging connector (Combo 2) maintaining full compatibility with the SAE specification for DC charging and the HomePlug Green PHY PLC protocol. In 2019 Tesla introduced the Model 3 with the CCS Combo 2 plug in Europe, but has not introduced ones with Combo 1 in the US. The Tesla started to roll out CCS plugs to Superchargers with the introduction of Model 3 in Europe.
Properties.
Connector.
The J1772-2009 connector is designed for single phase electrical systems with 120 V or 240 V such as those used in North America and Japan. The round diameter connector has five pins, with three different pin sizes (starting with the largest), for each of:
A 1 kHz square wave at ±12 volts generated by the EVSE on the control pilot line to detect the presence of the vehicle, communicate the maximum allowable charging current, and control charging begin/end.
The connector is designed to withstand 10,000 mating cycles (a connection and a disconnection) and exposure to the elements. With 1 mating cycle per day, the connector's lifespan should exceed 27 years.
Charging.
The SAE J1772 standard defines four levels of charging in the October 2017 revision: AC Level 1, AC Level 2, DC Level 1, and DC Level 2.
Their electrical ratings are specified as follows: 
As noted in Appendix M of the SAE J1772 standard document, a third AC charge method was also considered but never implemented. This "AC Level 3" mode would have used up to 96 kW at a nominal voltage of 208–240 V AC and a maximum current of 400 A. There is no reference to a "DC Level 3" charge method in the standard.
For example, the 2020 Chevrolet Bolt has a 66-kWh lithium-ion battery and a 7.2-kW onboard charging module (OBCM); with an EPA range of and energy efficiency of , it can use its portable charge cord charge at AC Level 1 (120 V, 12 A) to get up to of range per hour or go off a AC Level 2 charging unit (240 V, 32 A) to get up to of range per hour. Using an optional DC fast charging (DCFC) port, this model can also charge at up to 55 kW to get up to of range per half hour.
Some EVs have extended J1772 to allow 120 V charging at greater than 16 amps. This is useful, for example, at RV parks where TT-30 ("Travel Trailer" - 120 V, 30 A) receptacles are common. These allow charging at up to 24 amps. However this level of 120 V charging has not been codified into J1772.
Another extension, notably supported by Tesla, is Level 2 charging at 277 V. Like 208 V, 277 V is commonly found in North American commercial three-phase circuits.
Safety.
The J1772 standard includes several levels of shock protection, ensuring the safety of charging even in wet conditions. Physically, the connection pins are isolated on the interior of the connector when mated, ensuring no physical access to those pins. When not mated, J1772 connectors have no power voltages at the pins, and charging power does not flow until commanded by the vehicle.
The ground pin is of the first-make, last-break variety. If the plug is in the charging port of the vehicle and charging, and it is removed, the shorter control pilot pin will break first causing the power relay in the EVSE to open, stopping current flow to the J1772 plug. This prevents any arcing on the power pins, prolonging their lifespan. The proximity detection pin is also connected to a switch that is triggered upon pressing the physical disconnect button when removing the connector from the vehicle. This causes the resistance to change on the proximity pin which commands the vehicle's onboard charger to stop drawing current immediately. The vehicle can then release the control pilot which will cause the power relay to release.
Signaling.
The signaling protocol has been designed so that
The technical specification was described first in the 2001 version of SAE J1772 and subsequently the IEC 61851-1 and IEC TS 62763:2013. The charging station puts 12 V on the Control Pilot (CP) and the Proximity Pilot (AKA Plug Present: PP) measuring the voltage differences. This protocol does not require integrated circuits, which would be required for other charging protocols, making the SAE J1772 robust and operable through a temperature range of −40 °C to +85 °C.
Control Pilot.
Control Pilot (Mode): The charging station sends a 1 kHz square wave on the control pilot that is connected back to the protected earth on the vehicle side by means of a resistor and a diode (voltage range ±12.0±0.4 V). The live wires of public charging stations are always dead if the CP-PE (Protective Earth) circuit is open, although the standard allows a charging current as in Mode 1 (maximum 16 A). If the circuit is closed, then the charging station can also test the protective earth to be functional. The vehicle can request a charging state by setting a resistor; using 2.7 kΩ a Mode 3 compatible vehicle is announced ("vehicle detected") which does not require charging. Switching to 880 Ω the vehicle is "ready" to be charged and switching to 240 Ω the vehicle requests "with ventilation" charging in which case charging power is only supplied if the area is ventilated (i.e., outdoors).
The Control Pilot line circuitry examples in SAE J1772:2001 show that the current loop CP-PE is connected permanently on the vehicle side via a 2.74 kΩ resistor, making for a voltage drop from +12 V to +9 V when a cable is hooked up to the charging station, which activates the wave generator. The charging is activated by the vehicle by adding parallel 1.3 kΩ resistor resulting in a voltage drop to +6 V or by adding a parallel 270 Ω resistor for a required ventilation resulting in a voltage drop to +3 V. Hence the charging station can react by only checking the voltage range present on the CP-PE loop. Note that the diode will only make for a voltage drop in the positive range; any negative voltage on the CP-PE loop will shut off the current as being considered a fatal error (like touching the pins).
Control Pilot (Current limit): The charging station can use the wave signal to describe the maximum current that is available via the charging station with the help of pulse width modulation: a 16% PWM is a 10 A maximum, a 25% PWM is a 16 A maximum, a 50% PWM is a 32 A maximum and a 90% PWM flags a fast charge option.
The PWM duty cycle of the 1 kHz CP signal indicates the maximum allowed mains current. According to the SAE it includes socket outlet, cable and vehicle inlet. In the US, the definition of the "ampacity" (ampere capacity, or current capacity) is split for continuous and short term operation. The SAE defines the ampacity value to be derived by a formula based on the 1 ms full cycle (of the 1 kHz signal) with the maximum continuous ampere rating being 0.6 A per 10 µs up to 850µs (with the lowest 100 µs x .6 A = 6 A). Above 850µs, the formula requires subtraction of 640µs and multiplying the remainder by 2.5. For example (960 µs - 640 µs) x 2.5A = 80 A.
Proximity Pilot.
Proximity Pilot: The Proximity pin, PP (also known as "plug present"), as shown in the SAE J1772 example pinout, describes the switch, S3, as being mechanically linked to the connector latch release actuator. During charging, the EVSE side connects the PP-PE loop via S3 and a 150 Ω R6; when opening the release actuator a 330 Ω R7 is added in the PP-PE loop on the EVSE side which gives a voltage shift on the line to allow the electric vehicle to initiate a controlled shut off prior to actual disconnection of the charge power pins. However many low power adapter cables do not offer that locking actuator state detection on the PP pin.
Under IEC 62196 the Proximity Pin is also used to indicate the cable capacity - this is relevant for non-tethered EVSEs.
The resistor is coded to the maximum current capability of the cable assembly. The EVSE interrupts the current supply if the current capability of the cable is exceeded as detected by the
measurement of the Rc, as defined by the values for the recommended interpretation range. 
Rc is placed between the PP and PE, within the detachable cable assembly.
P1901 powerline communication.
In an updated standard due in 2012, SAE proposes to use power line communication, specifically IEEE 1901, between the vehicle, off-board charging station, and the smart grid, without requiring an additional pin; SAE and the IEEE Standards Association are sharing their draft standards related to the smart grid and vehicle electrification.
P1901 communication is compatible with other 802.x standards via the IEEE 1905 standard, allowing arbitrary IP-based communications with the vehicle, meter or distributor, and the building where chargers are located. P1905 includes wireless communications. In at least one implementation, communication between the off-board DC EVSE and PEV occurs on the pilot wire of the SAE J1772 connector via HomePlug Green PHY power line communication (PLC).
Compatible charging stations.
In North America and Japan, the Chevrolet Volt, Nissan Leaf, Mitsubishi i-MiEV, Mitsubishi PHEV, Chrysler Pacifica Hybrid, Toyota Prius Plug-in Hybrid, Smart electric drive, Ford Focus EV, Ford Fusion Energi, Ford Mustang Mach-E, Honda Clarity (Electric and Plug-in Hybrid), Kia Soul EV, Fiat 500e, and Mercedes-Benz GLC 350e PHEV all come with 120 V portable charging leads that couple a 120 V mains plug to the car's J1772 receptacle; in the countries where 220-230 V domestic mains electricity is common, the portable EVSE leads commonly supplied with the vehicle can perform a level 2 charge from a domestic mains plug, albeit at a lower current than a dedicated high-current charging station.
Products compatible with SAE J1772-2009 include:
Competing standards.
The proposal of the Mennekes connector initiated by RWE and Daimler has been added as a "Type 2" implementation to IEC 62196 (IEC Type 2) providing a single and three phase coupler. The connector was specified in the VDE-AR-E 2623-2-2 standard - this connector specifies up to 63 A three-phase (at 400 V in Central Europe) which makes for a maximum of 63 A × 400 V × = 43.6 kW. Additionally the IEC 62196-2 standard specifies a "Type 3" connector providing a single and three phase coupler with shutters. All plug types - including Type 1 (SAE), Type 2 (VDE) and Type 3 - share the same specifications for the pilot pin taken from the IEC 61851-1 standard.
Tokyo Electric Power Company has developed a specification solely for automotive high-voltage DC fast charging using the JARI DC connector, and formed the CHAdeMO ("charge de move", equivalent to "charge for moving") association with Japanese automakers Mitsubishi, Nissan and Subaru to promote it.