Since 2018, CharIN has driven the development of the Megawatt Charging System (MCS) as a solution for ultra-fast charging of commercial electric vehicles.
This system addresses the need to optimise operating times in heavy fleets, overcoming limitations of previous technologies such as the Combined Charging System (CCS).
The MCS is designed to support power levels of several megawatts, expanding daily range and facilitating electrification integration within regulated work cycles in freight transport.
Development of the MCS has involved collaboration among experts from multiple industries to define technical specifications, safety requirements, and communication protocols.
This cooperation aims to establish a global standard offering interoperability, safety, and efficiency across on-road, off-highway, maritime, and aviation applications.
The White Paper 2.0 by CharIN, published in May 2025, provides an updated framework for standards bodies and solution providers. It covers technical aspects of communication, electrical systems, and hardware to guide standardisation and infrastructure development.
The MCS is critical to reducing charging times and increasing operational efficiency in fleets. Below are five key points from the document.
1. Communication via Ethernet 10Base-T1S
The White Paper recommends adopting Ethernet 10Base-T1S as the physical layer for vehicle-to-infrastructure communication.
CharIN explains that “the MCS system is designed for currents six times higher and power up to ten times greater than CCS, so PLC is insufficiently robust against electromagnetic interference”.
Ethernet 10Base-T1S provides “high signal stability and immunity to disturbances”.
It also employs Physical Layer Collision Avoidance (PLCA), which “allocates transmission opportunities to each node in a round robin fashion, preventing collisions and retransmissions”.
This improves performance and communication stability compared to traditional PLC.
Ethernet natively supports TCP/IP and IPv6, facilitating interoperability and scalability.
The ISO 15118-20 protocol is recommended for advanced functions such as plug and charge, fleet management, and vehicle-to-grid (V2G).
CharIN notes that in controlled environments “omitting TLS 1.3 may be considered to simplify implementation, provided risks are managed”.
2. Electrical requirements and thermal management
The operating voltage range for MCS is 400 VDC to 1250 VDC, with connectors designed to withstand 1500 VDC.
Maximum continuous current has been validated up to 3000 A DC.
The document emphasises that “all charging points must support the full voltage range to avoid incompatibility”.
Thermal management responsibilities are shared: the vehicle controls its thermal limits, while the charging station maintains safe cable and equipment temperatures.
Requirements include insulation, short-circuit protection with peaks up to 70 kA, and temperature limits for contacts and surfaces.
Temperature sensors must comply with IEC TS 63379.
Cabling must withstand short-circuit energy of 11 MA²s, implying a minimum conductor cross-section of 25 mm² for protective earth.
3. Hardware: safety, ergonomics, and durability
Connectors must feature an electrically actuated retention mechanism securing connection during operation, including short circuits.
This mechanism “must provide feedback to the vehicle and operate independently of user or emergency commands”.
For trucks, the charging inlet is recommended on the left side behind the front axle, between 2 m and 4.8 m from the vehicle front.
This standardises infrastructure design and facilitates operation.
Ergonomics is critical given the connector and cable can exceed 10 kg. CharIN advises development of handling guidelines complying with workplace safety regulations.
Durability requirements specify at least 20,000 mating cycles, tested per UL 2251 and IEC 62196 standards.
Connectors must resist drops and meet ingress protection per IEC 62196 and forthcoming IEC TS 63379.
Adapters are discouraged due to safety, thermal, and communication protocol risks and are not covered under UL 2252.
4. Accessibility and automation in MCS infrastructure
Charging points must accommodate large vehicles, enabling drive-through manoeuvres.
The White Paper anticipates integration with automated electric vehicle supply equipment (aEVSE) for autonomous vehicles and long-haul applications.
It defines reference planes and axes for inlet position to facilitate robotic docking and undocking per ISO 12768-1 and IEC 61851-27.
This standardisation ensures compatibility with emerging robotic charging technologies.
5. International standardisation and ongoing updates
CharIN stresses cooperation among IEC, SAE, and other bodies to prevent divergent standards hampering interoperability.
The White Paper is a living document, subject to revisions incorporating technological advances and sector requirements.
CharIN “will continue supporting global harmonisation of MCS standards to ensure interoperable and safe charging infrastructure”.
