CCS Combo 2 versus CHAdeMO — DC fast-charging connectors compared (IEC 62196-3)

The guide on IEC 61851 charging modes covers the distinction between Mode 1-4, where Mode 4 stands for DC fast charging via an external charger. This article goes one level deeper: which connector systems are used for that DC fast charging, and why is that almost exclusively CCS Combo 2 in Europe?

The starting point: the Type 2 socket

The Type 2 socket (Mennekes, IEC 62196-2) is the European standard for AC charging (Mode 3, see the guide on the Control Pilot signal for the associated communication). It has seven pins: three phases, neutral, earth, and two pilot pins (Control Pilot and Proximity Pilot). Virtually every charge point in the Netherlands — home, workplace, or public charging hub — uses this socket for AC charging.

CCS Combo 2: the Type 2 socket extended with two DC pins

CCS (Combined Charging System) Combo 2, standardized in IEC 62196-3, literally builds on the Type 2 socket: the seven AC pins remain present, and below them two additional, thicker DC power pins are added (DC+ and DC-). A single vehicle inlet can therefore support both AC charging (using only the upper Type 2 portion) and DC fast charging (using the full Combo portion). Communication during DC charging runs over Power Line Communication (PLC) on the Control Pilot circuit, per ISO 15118 (with DIN 70121 as the precursor protocol) — the same physical pilot pair used for AC charging, but with a digital data signal instead of only a PWM duty cycle.

CHAdeMO: a fully separate connector system

CHAdeMO is an originally Japanese DC fast-charging standard with its own, round connector that is entirely separate from the Type 2 socket — a vehicle with a CHAdeMO inlet therefore has a physically distinct connection alongside (or instead of) the Type 2 inlet used for AC charging. Communication between vehicle and charger under CHAdeMO runs over a CAN bus, rather than the PLC communication used by CCS.

The two key differences at a glance

Aspect	CCS Combo 2	CHAdeMO
Connector shape	Builds on the Type 2 socket (AC pins + 2 DC pins)	Fully separate, round connector, independent of Type 2
Communication protocol	Power Line Communication (PLC) via ISO 15118 / DIN 70121	CAN bus
Number of vehicle inlets	One inlet for both AC and DC	Two separate inlets (Type 2 for AC, CHAdeMO for DC)
Status in the EU	Mandatory standard for public DC fast chargers	Being phased out on new European models, remains relevant for the existing fleet

Why the EU chose CCS Combo 2

The European Commission designated Combo 2 as the common standard connector for public DC fast chargers across the European Union. The practical advantage of the Combo approach is that a vehicle needs only a single inlet to support both AC and DC charging, instead of requiring two separate inlets as with CHAdeMO. Manufacturers serving the European market have therefore migrated their models almost entirely to CCS Combo 2; CHAdeMO remains practically relevant mainly for an older, still-circulating fleet (particularly earlier generations of Japanese models).

Power levels and future development

Both systems have been progressively developed toward ever-higher charging power over the years: CCS Combo 2 supports, at the latest public High Power Chargers (HPC), power levels well above 300 kW, while CHAdeMO's newer generation (co-developed with Chinese partners under the name ChaoJi) is likewise scaling to comparable power levels. For bidirectional charging (V2G, see the separate guide on that topic), CHAdeMO historically had a head start because early V2G implementations ran on CHAdeMO; CCS is catching up via the newer ISO 15118-20 revision of the communication protocol.

Practical relevance

When assessing or installing a public DC charge point in the Netherlands, CCS Combo 2 is nowadays the default; a charger that must also be able to serve (older) Japanese vehicles may need a separate CHAdeMO cable alongside the CCS cable. When diagnosing a charging problem, it is also relevant to know which communication protocol applies — a PLC coupling issue on CCS calls for a different diagnostic approach than a CAN-bus fault on CHAdeMO.

Common mistakes

Treating CCS Combo 2 and a plain Type 2 socket as the same thing — Combo 2 does include the Type 2 portion, but adds the DC pins; a charge point with only a Type 2 connector offers no DC fast charging.
Assuming every modern electric vehicle supports both CCS and CHAdeMO — most new European models now have only a CCS Combo 2 inlet.
Approaching a CCS communication problem (PLC/ISO 15118) as if it were a CHAdeMO CAN-bus fault — the underlying communication technology is fundamentally different and requires different diagnostic equipment.
Writing off CHAdeMO as fully obsolete — particularly with existing Japanese fleets and certain V2G applications, CHAdeMO remains relevant in practice.