Levels, types, and modes categorize EV chargers. The level indicates the maximum power the charger can deliver; the type describes the vehicle interface plug, and the mode represents how the charger connects to the grid.
This FAQ reviews the basic definition of EV charger levels, types, and modes and closes by looking briefly at some interrelationships between types and modes.
Charging levels
In North America, the Society of Automotive Engineers (SAE) J1772 standard specifies four levels of EV chargers. The levels are organized differently in Europe. The levels are:
Level 1 uses 120 Vac input, is limited to 1.8 kW, and delivers basic charging. It’s unavailable in Europe, where the standard residential service is 230 Vac.
Level 2 charging uses a 208/240 Vac input in North America. It uses a single-phase 230 Vac or a three-phase 400 Vac input in Europe. Level 2 can deliver up to 19.2 kW in North America and 22 kW in Europe. Level 1 and Level 2 chargers use the on-board charger (OBC) in the EV to control battery charging.
Level 3 refers to fast dc charging. It’s sometimes called dc Level 1 and dc Level 2 charging in North America. It bypasses the vehicle’s OBC and directly charges the batteries using a dc voltage that matches the battery pack voltage, typically 400 to 800 Vdc. These chargers are only available at commercial stations and are expected to reach 500 kW of charging power soon.
Types
The type defines the vehicle interface or plug. There are several EV charger types. They generally vary by region, but Tesla is an exception and has defined a proprietary type. Briefly, they are:
- North America and Korea use J1772 type 1 for ac charging and combined charging standard (CCS) type 1 for dc charging. CCS plugs can also be used for ac charging.
- Europe uses IEC type 2 for ac charging and CCS type 2 for dc charging.
- Japan uses J1772 type 1 for ac charging and CHAdeMO (‘CHArge de MOve’ or ‘move with charge’) for dc charging.
- China uses GB/T for ac charging with a unique dc interface.
- Tesla uses its proprietary National American Charging Standard (NACS) interface. Increasingly, however, Tesla cars can charge at non-Tesla chargers, and non-Tesla vehicles can be charged at Tesla Superchargers. For more details, see the FAQ, “Can non-Tesla vehicles use Tesla chargers and vice-versa?”
Combined charging system
As indicated above, combined charging system (CSS) connectors are used in North America and Europe. They are extensions of the IEC 62196 connector standard for ac charging, with two additional contacts added for fast dc charging. That enables a single connector to be used for either ac or dc charging. The overall connectors are very similar, but the pin layouts differ for Type 1, used in North America, and Type 2, used in Europe.
The initial standard supported charging rates up to 350 kW. The 400 kW CCS chargers have recently been deployed, and liquid-cooled variations of CSS connectors can handle up to 500 kW.
Figure 1. Dc fast-charging connector types. (Image: Dalroad).
Modes
There are four modes for EV charging, and mode 3 includes several variations:
- Mode 1: Plugs into a household ac socket. The maximum current is 16 A. There is no communication between the vehicle and the charger. Fuse protection via a residual current device (RCD) is mandatory in new installations but not always found in older installations. This mode is rarely used.
- Mode 2: It also plugs into a household ac socket but includes safety features in an in-cable control box (ICCB). The maximum current is 32 A, and the charging cable is equipped with an In-Cable Control-and-Protection Device (IC-CPD). This device includes residual current safety equipment (RCD), and communicates with the vehicle to control the charging process.
- Mode 3: Plugs into a charging station or wall box for an ac charge and doesn’t include an ICCB. The maximum current is 63 A. The charging station communicates with the vehicle and controls charging. Mode 3 is split into three cases:
- Case A uses a charging cable that is permanently connected to the vehicle. This case is rarely deployed.
- Case B uses a mobile ac charging cable carried with the EV with plugs on both ends, one for the EV and one for the charger. Case B is designed for use at public charging stations.
- Case C uses a charging cable that is permanently connected to the charger. The vehicle charging connector is used to plug into the EV charging inlet. Case C is common with private chargers.
- Mode 4: describes fast dc charging and includes communications capability and several safety features. Cables are permanently connected to the charger and plug into the vehicle inlet.
Figure 2. Examples of EV charger modes and corresponding connector types for North America, Europe, and China. (Image: Phoenix Contact).
Summary
EV charger levels, types, and modes indicate the maximum power the charger can deliver, the vehicle interface plug, and how the charger connects to the grid. They support a variety of ac and dc charging scenarios and vary by geographic region. In addition, Tesla has developed proprietary solutions.
References
- An introduction to electric vehicle rapid charging standards, Dalroad
- EV Charging connector types and Its applications, Electrify
- What charging modes are there for ac and dc charging?, Phoenix Contact
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