New series of DC energy meters for fast and megawatt EV chargers

LEM has released a new series of DC meters. The introduction of the DCES600 and DCES1500 enables DC charging infrastructure manufacturers to accelerate time-to-market for fast and megawatt charging solutions, with kWh billing services. The new meters deliver enhanced performance, flexibility, and system optimisation, making them particularly suited for applications such as e-truck charging.

The meters address a wide range of DC current-sensing requirements. They are designed to achieve class B accuracy at charger level with currents of up to 1500A, at operating temperatures from –40C to +85C without derating. Their high accuracy is maintained across the entire current range, ensuring precise measurements throughout the full charging cycle, from high currents at the start to low currents near completion.

The new meters comply with international legal metrology certifications and calibration standards, providing accuracy and traceability for kWh billing and regulatory compliance in EV charging applications. This, combined with the full-cycle sensing accuracy discussed above, is important when charging electric trucks, where the cost of transportation directly depends on the precise reporting of the amount of energy delivered during charging.

Designers can access the DCES meters via an RS-485 communication interface that incorporates cybersecurity features. These features include authentication of measurements using digital signatures and facilities that allow secure remote maintenance and firmware updates. These facilities are designed to help lower the operating costs of EV chargers built using the DCES meters. The company also offers a comprehensive set of APIs to enable quick and easy software integration, as well as other software tools to facilitate testing and product integration.

The meters are available with an optional remote display unit, the RDU, which provides OEMs and systems integrators with greater flexibility in designing the HMI compared to solutions with an integrated display. The RDU can be mounted on a front panel, DIN rail, or base plate, has a slim form factor, and does not require additional connections, such as communication lines or power sources, beyond its link to the DCES meters.

Both meters have a robust mechanical design, with a glass-fibre reinforced case, which offers insulation resistance at up to 1000VDC for the DCES600, and up to 1500VDC for the DCES1500. They also provide large power terminals with large current contact areas. The DCES600 features two M10 studs, enabling busbar termination to be screwed down onto a contact area measuring 33mm x 36mm. In the DCES1500, there are four M12 studs in two pairs, with each pair offering a combined contact area of 45mm x 100mm. The busbars for these meters are specified to operate at up to 110C. Both meters are supplied with a protective cover and seals.

The DCES meters offer real-time reporting of voltage, current, temperature and energy. These values can be used for direct energy measurement, for example, for billing purposes, and as part of a system management strategy to ensure the end equipment is kept within safe operating limits through remote system diagnostics.

Applications for the DCES modules include DC fast charging stations, megawatt charging hubs, fleet and depot charging, and OEM integration.