Mi az a DC mérőműszer, és hogyan működik?

Unlike traditional systems based on alternating current (AC), DC installations require specialized metering solutions that ensure precision, reliability, and compliance with applicable standards.

A DC meter (DC Billing Meter) is a device dedicated to measuring energy and power in direct current circuits. Modern meters, such as the DCBM series from LEM, address the growing demand for accurate energy measurement in photovoltaic installations, electric vehicle chargers, energy storage systems, and industrial automation systems.

This article will introduce what a DC meter is, how it works, where it is used, and why the solutions offered by LEM are currently among the most advanced and professional on the market.

What is a DC meter and how does it work?

A DC meter (DC Billing Meter) is a specialized measuring device designed to monitor the flow of electricity in direct current circuits. Unlike classic AC meters, which dominate household and commercial grid installations, DC meters are designed with the specific characteristics of DC systems in mind, such as energy storage, photovoltaic installations, UPS backup systems, or electric vehicle charging infrastructure.

In designs like the DCBM series from LEM, measurement is based on the Hall effect. This is a contactless current measurement technology that uses the phenomenon of transverse voltage generation in a conductor placed in a magnetic field produced by the flowing current. This allows for very accurate determination of current intensity without interfering with the current path.

This technology brings several benefits:

• High measurement accuracy – independent of temperature and component aging,
• Galvanic isolation – complete separation of the measuring circuit from the high-voltage circuit, ensuring safety for people and devices,
• Installation safety – no need for shunts or current transformers, which can be damaged or cause interference,
• No voltage drop in the current path – particularly important for high-current DC systems.

The DCBM meter measures not only current but also DC voltage (up to 1000 V) and calculates actual energy consumption over time (Wh, kWh). The device performs these measurements in real time, recording energy flow in both directions (charging and discharging), making it an ideal solution for energy storage systems.

Integrated communication via Modbus RTU allows easy integration of the meter with supervisory systems (e.g., SCADA, BMS, EMS), enabling remote monitoring, data archiving, and use for billing end customers. As a result, the DC meter is no longer just a measuring tool—it becomes a strategic component in energy management in modern low- and zero-emission installations.

Where are DC meters used?

DC meters are used wherever there is a need to accurately monitor electricity flow in DC circuits—for both diagnostic and billing purposes. With the development of DC-based technologies such as energy storage, photovoltaics, and EV chargers, the demand for precise and certified measurements in these environments is increasing.

One of the main application areas is EV charging stations, especially those operating in fast DC charging mode. In such installations, the meter not only monitors the amount of energy delivered to the vehicle but also enables direct billing of the end user in accordance with legal requirements. Thanks to MID compliance and accuracy class C, DCBM meters can be successfully used for invoicing.

Another important application is in energy storage systems (ESS), which are gaining popularity for local self-consumption, grid stabilization, and energy cost optimization. In such applications, DC meters allow measurement of energy during both charging and discharging phases. This enables precise management of battery operation cycles and analysis of their operational efficiency.

Equally important is their use in photovoltaic installations, where DC meters are used to monitor the performance of individual PV strings before energy is converted to AC by inverters. This type of measurement allows for early detection of module malfunctions and optimization of energy production.

In the industrial sector, DC meters are used in switchboards and automation systems where DC power supply is often used to power critical control systems, measuring devices, or emergency systems. Their presence enables precise energy consumption monitoring within individual installation sections and improves the facility's energy security.

Specialized sectors should also be mentioned, such as railways, telecommunications, and data centers, where DC power supply is standard. In these environments, meters serve not only an informational but also an operational function—providing real-time energy consumption insight and supporting energy optimization processes.

DCBM meters from LEM – a market leader

If you're looking for a solution that combines top measurement quality with modern technology and full operational safety – the DCBM series from LEM is an unrivaled choice. These compact yet highly advanced devices are designed for demanding direct current applications. From EV charging stations and energy storage systems to industrial switchboards—wherever accuracy, durability, and standards compliance matter.

What sets them apart? Primarily, they do not rely on shunts or transformers, which can lose accuracy over time or cause interference in the current path. Instead, LEM uses contactless Hall effect-based measurement, providing full galvanic isolation and user safety—even at voltages up to 1000 V.

Depending on your needs, there are three models to choose from:

• DCBM 100 – ideal for smaller systems, measures current up to 80 A at voltages up to 1000 VDC.
• DCBM 400 – a universal solution, up to 400 A / 1000 VDC – suitable for most commercial and industrial applications.
• DCBM 600 – the most powerful in the family, designed for high loads – up to 600 A at 1000 VDC.

Each model is MID certified, meaning they can be used for billing end users – e.g., in EV charging stations or PV systems with energy storage.

Additionally, they offer easy DIN rail mounting, built-in Modbus RTU interface, and accuracy class C. In short: everything you need to accurately measure, control, and bill energy in modern DC systems.

How does the DCBM meter work?

The precision of LEM’s DCBM meters is driven by proven and safe Hall effect-based measurement technology. In practice, this means that the device does not need physical contact with the conductor to know how much current is flowing in the circuit. As long as the current creates a magnetic field, the Hall sensor instantly detects it and calculates the current value. The entire measurement takes place with full galvanic isolation, enhancing the safety and reliability of the system, even at high voltages.

But that’s just the beginning. DCBM meters are packed with practical features:

• DC voltage measurement up to 1000 V – one meter, many applications.
• MID compliance and accuracy class C – ready for official energy billing, e.g., with EV station users.
• Modbus RTU on board – fast and easy integration with BMS, SCADA, and other energy management platforms.
• DIN rail mounting – installation takes just a moment and doesn’t require special tools.
• IEC 61010 compliance – guaranteed resistance to interference and full operational safety.

DCBM is not just a meter but a complete tool for modern DC energy management. And one that simply works – reliably, precisely, and under any conditions.

Summary

In a world where more and more energy systems are based on direct current – from EV charging stations and PV installations to industrial switchboards and energy storage – accurate, safe, and certified DC metering is no longer optional but essential.

LEM’s DCBM meters are the answer to these needs. With modern Hall effect-based measurement technology, full galvanic isolation, and compliance with the latest standards, these devices perform where there is no room for compromise. Whether you're managing a charging infrastructure, a photovoltaic system, or an industrial DC power setup – DCBM is the tool that will provide you with precision, peace of mind, and control.

When considering an investment in a DC metering system, it’s worth choosing a solution that combines technology, durability, and billing readiness – and that’s exactly why LEM DCBM is the choice of professionals.