EVSE calibration and legal metrology
EVSE calibration and energy measurement verification
Compare the energy recorded by a charging station with a traceable reference. Control the load, measure the deviation and document the result.
Your path to mobile EVSE calibration
Plan the mobile EVSE measurement setup.
Review the measurement task, certified Calimera system and published field use case. Then agree the reference chain and requirements for the target market.
Energy measurement at the charging point
Measure the energy your customer receives.
Compare the station’s energy reading with a traceable reference at defined operating points. Record the deviation and measurement conditions to evaluate energy accuracy separately from charging function.
Controlled operating points
Set voltage, current and dwell time so the same measurement can be repeated after an adjustment, repair or software change.
The installed charging path
Measure at the charging connection with real energy flowing. This includes the cable path and the effects present during the charging event.
Comparable results
Record station and reference values together to compare stations and repeated tests within the documented campaign.
Voltage, current and test duration
Cover the voltage and current combinations that matter.
Test the relevant 400 V and 800 V charging bands and the boundaries of the station’s operating range. Match the calibration load to every required voltage and current point as well as the power rating.
| Example operating point | What it reveals |
|---|---|
| 150 V × 500 A = 75 kW | A demanding high-current point at low voltage. The load must reach the current even though the total power is below its headline rating. |
| 1,000 V × 10 A = 10 kW | A high-voltage point at low current. Stable control and a suitable reference range matter here. |
Plan the campaign around the station's supported range and the applicable procedure.
Preparation, measurement and reporting
Prepare the campaign, measure on site and document the result.
- Prepare the campaign. Define operating points, dwell times and the information needed for the report in comframe.
- Connect at the station. Establish the charging communication and connect the reference measurement and controlled load.
- Run and review. Follow voltage and current during the measurement; compare the station's energy value with the reference.
- Keep the result. Store the measured values and campaign data and prepare the measurement report for review.
Controlled real-load calibration
Compare station and reference values during real charging.
With Easy Chester Calimera’s controlled load, the reference and station meter observe the same energy transfer at an installed station, including the selected operating point and measurement path.
Include load stability, charging communication and thermal behaviour in the measurement conditions. Set voltage, current, duration and synchronization for the applicable verification procedure.
Compact meter-circuit setups have a narrower test boundary: stimulating selected conditions does not reproduce the complete station under charging load. The selected method must therefore match the required EVSE verification scope.
Understand real-load calibration and measurement-scope limits →
Requirements and product capability
Plan measurements for the applicable requirements.
| Reference | What it addresses | How Calimera supports the work |
|---|---|---|
| VDE-AR-E 2418-3-100 | Measurement systems for AC and DC charging under German legal metrology. | Controlled energy comparison and documented measurement campaigns. |
| OIML G 22:2022 | International guidance for EVSE metrological requirements and tests. | A repeatable load and reference measurement for the selected points. |
| NIST Handbook 44, §3.40 (2026) | EVSE test procedures, including separate DC type-evaluation and field-verification methods. | Configurable charging conditions and recorded station/reference values. |
| GM-P 6.8 Elektromobilität (20 February 2026) | German procedures for verification and in-service investigation of EVSE metering systems. | Reproducible test conditions and documented reference comparisons for the applicable procedure and selected configuration. |
Calibration provides a measurement result. Formal verification follows the applicable national procedure and authorization.
Easy Chester Calimera
Calibrate installed charging stations on site.
Easy Chester Calimera brings charging communication, reference measurement, a controlled load and comframe to the installed charging station in a mobile setup.
PTB-certified Easy Chester CalimeraView certification detailsChoose the Calimera configuration by its load rating, reference-meter range and required operating points. The product configuration table separates named catalogue variants from CONTINUOUS and Boost mode figures. Confirm voltage, current, holding time and cooling for the measurement procedure.
Our calibration experience also comes from the laboratory at comemso eMobility Services GmbH. Its published ISO/IEC 17025 accreditation documents describe the accredited scope. View the laboratory accreditation.
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Practical questions
Practical questions about EVSE calibration
Why use a controlled load instead of a vehicle?
A controlled load makes the voltage and current operating points reproducible within the configured test range. A normal electric vehicle sets its charging demand according to battery state, temperature and charging curve. A vehicle and adapter therefore cannot freely select and reliably repeat all points required for a complete metrological test.
The PTB presentation explains this limitation and states: “Benötigen ein voll-ausgestattetes Labor an der Ladeeinrichtung”.
The permitted method depends on the task: calibration, formal verification (Eichung) and an in-service investigation (Befundprüfung) have different purposes. GM-P 6.8 includes procedure-specific vehicle use for a Befundprüfung; this is not a universal ban on vehicle-based checks. The applicable procedure determines the required test points and any permitted exceptions.
Does a successful charging session prove energy accuracy?
No. Functional charging and energy accuracy answer different questions. Calibration compares the recorded energy with a suitable reference at known conditions.
Can one setup cover every charging station?
Match the required interfaces, voltage/current range, continuous load capacity and reference uncertainty to the station. Share its data and the required test points so we can select the configuration for the campaign.
Plan the EVSE measurement procedure.
Define the measurement task, applicable procedure, reference instrument and operating points. Use these requirements to select the calibration-system configuration and plan repeatable energy transfer and the required records.