1. Why EV Charger Metering Is "Trade Settlement" (Mandatory Verification Measuring Instruments)
Selling power to drivers makes an EV charger atrade settlement measuring instrument, so the watt-hour meter / metering module must be subject to mandatory verification (per JJG verification regulations), and it may not continue billing if it fails periodic verification. Every order amount on the operator platform comes from metering data — metering accuracy and compliance directly affect the operator's license to operate.
2. AC Charger Metering Scheme (Class 1 Watt-Hour Meter)
| Item | Requirement |
|---|---|
| Metering method | Watt-hour meter inside the charger, or an external meter box |
| Watt-hour meter accuracy | Active energy Class 1 or Class 2 (per settlement requirements; Class 1 recommended for commercial chargers) |
| Size | Single-phase 5(60)A / three-phase 5(80)A direct connection |
| Communication | RS485/power line carrier, data uploaded to the operator platform |
| Verification | Initial mandatory verification + periodic verification |
7kW single-phase chargers mostly use an internal meter; 11kW/21kW/42kW three-phase chargers can use anindependent meter box(one metering cabinet shared by multiple chargers), which simplifies meter reading and verification management.
3. DC Charger Metering Scheme (DC meter + shunt)
- DC energy meter: active energy class 0.5 or class 1, sampling high current via shunt / Hall sensor (30–250kW chargers can draw several hundred amps);
- Shunt: 75mV standard output, class 0.5 accuracy, calibrated as a matched set with the DC meter;
- Metering point: whether the meter sits at the charging module output (billing basis) or the input (loss basis) must be defined —billing at the output (energy actually delivered to the vehicle owner)is standard practice;
- Verification: the off-board charger as a whole is verified for indication error per the verification regulation.
4. Time-of-Use Billing and Fee Control (operator-side configuration)
Once metering data is uploaded to the operating platform, it drivestime-of-use tariffs (peak, valley, flat, critical peak)and fee control logic: card / QR code authentication → metering starts → real-time billing → settlement. On the distribution cabinet side, you need to providereliable auxiliary powerfor metering and communications (an independent miniature circuit breaker is recommended for the metering circuit), plus reserved mounting space and communication wireways for the operator's meters.
5. Distribution Cabinet Enclosure Fabrication Scope (What Zhejiang Golden Unicorn Does)
Zhejiang Golden Unicorn undertakesDistribution cabinet enclosure fabrication for EV charging stations: the incoming cabinet, metering cabinet and feeder cabinet enclosures for a charging station are built to drawing — bending and welding, painting, busbar fabrication, meter mounting positions and CT cutouts, communication wireways, ventilation and heat dissipation features. Charging modules, rectifiers, the billing control unit (TCU) and energy meters are supplied by partners or installed as customer-supplied items; enclosures ship with cutout drawings and inspection records, FOB origin (Hangzhou).
FAQ FAQ
What metering accuracy is required for AC charging stations?
For trade settlement, AC energy meters must be active energy class 1 or class 2; for operator scenarios, class 1 is recommended, and the meter is subject to mandatory verification per the verification regulation.
Which end is the DC charger meter installed on?
Standard practice is to install it at thecharging module output(billing for the energy actually delivered to the vehicle owner); confirm against local operating and regulatory requirements.
Do meters need periodic verification?
Need. Trade settlement measuring instruments fall under mandatory verification; if verification is overdue or fails, no billing is permitted.
Can Zhejiang Golden Unicorn supply a complete charging station?
Golden Unicorn works toenclosure fabrication scopeWe take on the charging station distribution cabinet enclosures (including metering cabinet enclosures and mounting structures); charging modules, TCUs, energy meters and similar items are supplied by partners, and we handle the enclosure structural interface.
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