MCS testing for megawatt charging stations

Charging capacities of up to 3.750 kW, currents of 3.000 A, and voltages up to 1.250 V present entirely new challenges for measurement technology. If heavy commercial vehicles are to be charged in less than 30 minutes, the testing technology must keep pace.

MCS testing and calibration in the megawatt range

MCS testing is rapidly gaining importance with the expansion of the megawatt charging infrastructure for heavy commercial vehicles. The Megawatt Charging System (MCS) enables charging capacities of up to 3.750 kW, thus placing entirely new demands on measurement technology, calibration, and legally compliant verification. While CCS charging stations operate at a maximum of 400 kW, MCS pushes the limits almost tenfold.

For testing service providers, energy suppliers, and charging station operators, this raises fundamental questions regarding metrological verification. ZERA, a specialist in meter testing technology and e-mobility testing, supports this development with over 100 years of experience in precision measurement technology. This article examines the technical fundamentals, normative frameworks, and metrological challenges of MCS testing.

Fundamentals of the Megawatt Charging System for commercial vehicles

Technical specifications and performance data

The Megawatt Charging System was developed by the CharIN organization as a global standard for high-performance charging of heavy vehicles. Work on the specification has been ongoing since 2018, supported by over a dozen manufacturers and research institutions worldwide. With a maximum voltage of 1.250 V DC and a charging current of up to 3.000 A, the system achieves a peak power of 3.750 kW.

The MCS connector is based on a single-plug design with integrated liquid cooling and Ethernet-based communication. Compared to the established Combined Charging System (CCS), MCS represents a significant technological leap. CCS charging stations operate at a maximum of 1.000 V and 500 A, which corresponds to a power output of up to 400 kW.

Vehicle classes and areas of application

The primary target group for the MCS comprises heavy commercial vehicles in classes 6 to 8 according to the US classification. This includes long-haul trucks, distribution vehicles, and heavy tractor units with battery capacities of several hundred kWh. In the future, the standard is also suitable for buses, construction equipment, and ships with high energy demands.

The MCS connector is positioned on the left side of the vehicle at hip height and meets the UL2251 touch-safe certification. V2X capability enables bidirectional charging and opens up additional business models in the vehicle-to-grid sector for operators.

Norms and standards for MCS testing

IEC TS 63379 as the basis for the connector specification

IEC TS 63379, a technical specification, defines the requirements for connectors, vehicle inlets, and cable assemblies for conductive DC charging in the megawatt range. The publication of this standard in February 2026 marks a significant milestone for the entire MCS testing process. For the first time, manufacturers and testing laboratories will have a binding basis for the conformity assessment of MCS components.

In parallel, the IEC is working on the standard IEC 61851-23-3, which defines specific requirements for MCS charging equipment (EVSE). As of 2026, this standard is still under development and is expected to be published in the same year. For MCS testing, this means a dynamic standardization landscape in which testing procedures must be continuously adapted.

Charging communication according to ISO 15118-20

Charging communication in the MCS system is based on the ISO 15118-20 protocol, which governs high-level communication between the vehicle and the charging station. A specific amendment introduces additional service IDs for MCS-specific functions. Plug-and-charge capability enables automatic authentication and billing without manual intervention.

For MCS testing, this necessitates the verification of both the electrical parameters and the communication protocols. Low-level communication operates with narrower voltage bands than CCS and places particular demands on the measurement accuracy of the test systems used.

Challenges of MCS testing in the megawatt range

Thermal management at 3.000 A charging current

The extreme charging currents of up to 3.000 A generate significant thermal stress on the connector, cable, and vehicle inlet. Test events at the National Renewable Energy Laboratory (NREL) with prototypes from seven manufacturers have shown that active cooling of both the connector and the inlet is absolutely essential at maximum current. Without any cooling, the charging current can only be safely operated up to a maximum of 350 A.

Cooling only the connector increases the permissible current to 1.000 A. Only combined cooling of both components enables full MCS operation at 3.000 A. For MCS testing, this means that test systems must reliably simulate the thermal conditions during normal operation and under extreme load conditions.

Measurement uncertainty and accuracy requirements

Measurement uncertainty in the megawatt range presents test facilities with particular challenges. The low-level communication of the MCS operates with narrower voltage bands than comparable CCS systems, and test systems must reliably identify these narrow signal levels. The required precision increases proportionally to the power output.

As of 2026, final test specifications for MCS testing are still under development. Existing test procedures should be modular to allow for easy adaptation to standardization changes. The measurement technology used must enable performance tests up to 3.750 kW with reproducible results.

Calibration law and metrology for MCS charging stations

Lack of legally compliant DC meters in the megawatt range

German calibration law stipulates that electricity at charging stations must be billed in kilowatt-hours. Several approved DC meters exist for CCS charging stations that meet this requirement. However, such measuring devices are completely lacking in the megawatt range, and no manufacturer currently offers legally compliant DC meters for power outputs in the MW range.

The HoLa research project has documented this problem and recommends temporarily suspending the mandatory calibration of MCS charging stations. Alternatively, time-based tariffs could replace kWh billing until suitable metering systems are available in sufficient numbers. This creates regulatory uncertainty for MCS infrastructure operators when making investment decisions.

Time-based tariffs as an alternative to kWh billing

Time-based billing models offer a pragmatic solution for the transition phase. Instead of measuring the exact amount of energy, the charging process is billed in time units. This model requires less measurement effort but has disadvantages for users with varying charging speed profiles.

The regulatory framework for time-based MCS tariffs is currently being discussed at the European and national levels. The following table compares the calibration requirements of both charging systems:

For long-term MCS testing, the development of legally compliant DC meters in the megawatt range remains a key prerequisite. Only when Calibration solutions Since these are available for this performance range, complete metrological security can be guaranteed.

MCS testing and CCS testing compared

Performance areas and technical differences

The differences between CCS and MCS relate not only to charging power, but also to connector design, cooling concept, and communication architecture. CCS charging stations use Combo 1 or Combo 2 connectors with maximum specifications of 1.000 V and 500 A. The MCS connector uses a completely new single-plug design with integrated liquid cooling for high-current operation.

CCS uses Power Line Communication (PLC) for communication, while MCS relies on Ethernet and ISO 15118-20. For MCS testing, test systems must be able to support both communication paths to ensure complete verification.

Transferable testing procedures and new requirements

Fundamental metrological principles of CCS testing can be applied to MCS testing. Accuracy classes, PTB traceability, and DAkkS calibration remain key quality characteristics regardless of the performance range. Those with prior experience in the DC testing technology who brings with them, possesses essential skills for the MCS exam.

New requirements arise from the significantly higher currents and voltages, as well as the need for thermal monitoring during the testing process. Communication tests are expanded to include MCS-specific service IDs and the validation of low-level signal levels. Test systems must be scalable to cover both existing CCS tests and future MCS verifications.

MCS infrastructure in Europe and current pilot projects

HoLa research project and field tests in Germany

The HoLa (High-Performance Charging in Long-Haul Trucking) research project, funded by the Federal Ministry for Digital and Economic Affairs, operates eight MCS charging points and ten CCS charging points in real-world logistics operations. At these locations, insights are gathered regarding network integration, operational management, and metrological requirements. The results are directly incorporated into the further development of testing procedures and standardization efforts.

The project has provided valuable practical data for MCS testing, particularly regarding the challenge of legally compliant billing. The experience gained shows that, in addition to pure charging power, grid connection capacity and load management are key factors for successful MCS operation.

Mercedes-Benz Trucks and MAN are driving MCS technology forward.

At the beginning of 2026, Mercedes-Benz Trucks conducted a field test with the eActros 600, testing MCS charging capabilities on a long-haul journey to Sweden. ABB E-mobility and MAN demonstrated megawatt charging on the eTruck for the first time, achieving charging capacities of over 1.000 kW in real-world operation. Daimler Truck reported charging capacities that broke the previous barrier in electric vehicle charging.

These manufacturer tests demonstrate that MCS technology is leaving the prototype testing phase and moving into near-series production. For the Testing technology in the field of e-mobility This means growing demand for reliable and scalable testing solutions. The expansion of MCS infrastructure along European long-distance transport corridors will gain significant momentum in the coming years.

Testing technology and calibration for megawatt charging stations

Requirements for next-generation testing systems

MCS testing requires test systems capable of scalable power tests from 500 kW to over 2.000 kW. In addition to pure power measurement, these systems must support validation against ISO 15118-20 and the future IEC 61851-23-3. Highest accuracy classes and integrated thermal monitoring are among the core requirements for future test equipment.

Traceable calibration to national standards remains the foundation for reliable measurement results, even in the megawatt range. DAkkS-accredited calibration laboratories guarantee metrological security and build trust with operators and regulatory authorities. We contribute over 100 years of experience in meter testing and precision measurement technology to the development of future-proof testing solutions.

With a Test bench for electromobility With our extensive expertise in DC testing technology, we have a solid foundation for meeting the requirements of MCS testing. The combination of traditional metrology competence and innovative e-mobility testing technology enables us to support operators and manufacturers on their path to megawatt-scale charging infrastructure. Contact us for a free consultation regarding your specific testing requirements.

Frequently asked questions about the MCS exam

What is the Megawatt Charging System (MCS)?

The Megawatt Charging System (MCS) is a charging standard developed by the CharIN organization for heavy commercial vehicles, buses, and other large electrical consumers. With a maximum charging capacity of 3.750 kW (3.000 A at 1.250 V DC), MCS enables the fast charging of vehicles with very large battery capacities in under 30 minutes.

What standards apply to the MCS test?

The central standard is IEC TS 63379, which specifies connectors and vehicle inlets. Additionally, IEC 61851-23-3 regulates the requirements for charging equipment, and ISO 15118-20 governs charging communication. All three standards were at different stages of maturity in 2026 and are continuously being developed further.

When will MCS charging stations be available?

The first MCS charging points are already operational as part of research projects like HoLa. A broader commercial rollout is expected from 2027 to 2028. Manufacturers such as Mercedes-Benz Trucks and MAN are already testing MCS under real-world conditions in long-haul transport.

How is measurement accuracy ensured at MCS?

Measurement accuracy is based on traceable calibration by DAkkS-accredited laboratories and adherence to defined accuracy classes. Testing systems must reliably detect the narrower voltage bands of MCS low-level communication and deliver reproducible results.

What challenges does calibration law pose for MCS?

The biggest challenge is the lack of legally compliant DC meters in the megawatt range. Since German calibration law mandates billing accurate to the kWh, interim solutions such as time-based tariffs are being discussed until suitable measuring devices are available.