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Importance of EV Testing 

Why EV Charger Accuracy Matters
​Electric Vehicle (EV) adoption is growing worldwide, and ensuring accurate energy measurement is critical for fair billing, safety, and regulatory compliance. Metrological testing ensures that EV chargers provide precise energy readings, preventing overcharging or undercharging of consumers.

Key Reasons for EV Charger Testing:
✅ Fair Billing – Customers should be charged only for the energy they consume.
✅ Regulatory Compliance – EV chargers must meet international metrology standards (OIML R 46, IEC 62053).
✅ Consumer Confidence – Reliable charging infrastructure boosts trust in EV adoption.
✅ Prevention of Fraud – Prevents inaccurate readings that could lead to financial loss.

Types of Testing Methods

​From a metrological perspective, verifying the accuracy of Electric Vehicle (EV) chargers involves a combination of legal metrology, traceability to national/international standards, and field testing. Here’s how it can be done:
1. Standards and Regulations
  • Many countries have legal metrology requirements for EV chargers, ensuring that users are charged correctly for the electricity they receive.
  • Common standards include:
    • OIML R 46 (International Organization of Legal Metrology – Active electrical energy meters)
    • IEC 62053-21/22 (Electricity metering equipment)
    • MID (Measuring Instruments Directive, 2014/32/EU) in Europe
    • NIST Handbook 44 (USA)
2. Calibration and Traceability
  • EV chargers must be calibrated against reference standards that are traceable to national measurement institutes (NMI), such as:
    • National Institute of Standards and Technology (NIST, USA)
    • Physikalisch-Technische Bundesanstalt (PTB, Germany)
    • Badan Standardisasi Nasional (BSN, Indonesia)
  • A reference meter with a higher accuracy class (e.g., 0.1%) is used to compare against the EV charger’s internal meter.
3. Testing Methods
​a) Laboratory Testing
  • Conducted in a controlled environment with precision instruments.
  • A calibrated energy meter (±0.1% accuracy) is used to compare readings against the EV charger’s meter at different load levels.
  • Ensures compliance with IEC 61851 (Conductive charging systems) and ISO 15118 (Vehicle-to-grid communication).
b) Field Testing (In-Situ Verification)
  • Portable test systems are connected to the EV charger and compare real-time measurements.
  • Parameters tested include:
    • Voltage (V) and Current (A)
    • Energy Consumption (kWh)
    • Power Factor (PF)
    • Total Harmonic Distortion (THD)
    • Temperature & environmental effects
c) Time-Based and Smart Metering Validation
  • Some chargers charge based on time-based tariffs.
  • Smart meters should be tested for time synchronization errors, data logging accuracy, and communication with backend systems.
4. Error Allowance & Acceptance Criteria
  • Most regulations allow a ±1% to ±2% error margin for billing purposes.
  • Any deviation beyond this must be corrected via recalibration or firmware updates.
5. Certification & Periodic Inspection
  • EV chargers should be type-approved by regulatory bodies before commercial use.
  • Periodic inspections (e.g., annually) ensure continued compliance with metrological standards.

​Our Solution (Most Popular)

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On-Site Testing with EMOB200 – The Ultimate EV Charger Verification Tool
​The EMOB200 by ZERA GmbH is a state-of-the-art portable tester designed to verify both AC and DC EV chargers on-site. This tool ensures high accuracy, real-time testing, and compliance with industry standards.

Key Features of EMOB200:
🔹 High Accuracy – ±0.1% precision for energy measurements.
🔹 Portable & Battery Operated – No external power supply needed for field testing.
🔹 Supports AC & DC Chargers – Tests up to 32A AC and 200A DC chargers.
🔹 Real-Time Data Analysis – Wi-Fi enabled tablet interface for remote control & real time view on browser via IP address
🔹 OCPP Protocol Support – Ensures compatibility with modern charging networks.

How EMOB200 Ensures Compliance & Accuracy
​1️⃣ Connect EMOB200 to the EV charger via standard connectors.
2️⃣ Measure voltage, current, power, and energy output.
3️⃣ Compare results with charger’s internal meter – identifying any discrepancies.
4️⃣ Generate automated test reports for compliance audits.
5️⃣ Ensure accuracy & efficiency of EV charging stations!

Trusted by Industry Leaders
​The EMOB200 is widely used by:
✅ Government agencies & regulatory bodies
✅ EV charger manufacturers
✅ Energy metering service providers
✅ EV fleet operators