EV Charging Pile Operation & Maintenance | Reduce Failures, Extend Equipment Service Life

Practical Tips for Service Life Extension:

1.Equipment Selection: Prioritize equipment complying with national standards and with 3C certification. Exercise caution with stripped-down or refurbished units. Starting from August 1st, 3C certification serves as a fundamental compliance requirement for charging station construction to facilitate qualification review and operation. If budget permits, opt for liquid-cooled models with IP54 rating or higher. Provided that valid 3C certification is obtained and manufacturers do not falsify documents, the basic quality is guaranteed. Differences among brands mainly lie in workmanship, components and after-sales service. There is no need to blindly pursue well-known brands for small-batch purchases or charging stations built in small cities.

2.Installation Environment: Install in shaded, well-ventilated and dry locations whenever possible. For outdoor household wall-mounted chargers, provide shading. Use protective covers when the equipment is idle.

3.Periodic Maintenance: Required for both residential and commercial chargers. Clear dust accumulated in the cabinet and dust filters to ensure heat dissipation; fasten wiring connections; inspect charging cables for damage and check whether charging pins are loose.

4.Rational Operation: Avoid continuous full-load operation and reserve power redundancy. Example: Set a 30 kW household charger to run at 25 kW; adjust a 120 kW commercial charger to 110 kW to reduce component wear and tear

Operation & Maintenance Inspection: Wearing Part Failures & Root Causes

Ⅰ.Wearing Parts Common to AC and DC Chargers

1.Charging Gun (Most Frequently Failed)

Failures: Poor contact, charging interruption, locking failure, sheath damage, broken cable conductors; liquid-cooled gun leakage.

Causes: Frequent plugging/unplugging, dragging and rolling, aging under sunlight, contact pin ablation, drops and impacts.

2.Cooling Fan

Failures: Abnormal noise, stall, insufficient rotating speed, overheat protection, power derating.

Causes: Dust accumulation, bearing wear, high-temperature aging, insect jamming (including cabinet fans and module fans).

3.AC/DC Contactor / Relay

Failures: Failure to start charging, abnormal power cut, contact arcing and welding, tripping.

Causes: Frequent switching on/off, contact ablation caused by high-current electric arcs; DC contactors have the highest failure rate.

4.Emergency Stop Button, Cabinet Door Lock, Mechanical Latch

Failures: Emergency stop button fails to reset, abnormal opening/closing of cabinet door, charging gun locking failure.

Causes: Mechanical wear, water ingress and rusting, external impact.

5.Display Screen, Indicator Light

 Failures: Screen distortion, black screen, touch malfunction, indicator off.

Causes: Backlight aging, moisture ingress, static electricity, rough operation.

6.Surge Protective Device (SPD)

Failures: Tripping during thunderstorms, no power output, red alarm on surge module.

Causes: Lightning strike, power grid surge impact, varistor failure.

7.Circuit Breaker, Residual Current Device (RCD)

 Failures: Frequent nuisance tripping, failure to close, heating at wiring terminals.

Causes: Aging, current surge, loose terminals; external circuit breaker failures account for a large proportion.

II. Wearing Parts Exclusive to DC Chargers

1.Power Module (Core High‑value Component)

Failures: No fault alarm yet no output, power degradation, overheating alarm, shutdown.

Causes: Long-term full-load operation, poor heat dissipation, harmonic impact, component aging.

2.DC Support / Filter Capacitor

Failures: Bulging and liquid leakage, excessive ripple, unstable charging, module protection triggered.

Causes: High temperature, ripple current, aging and degradation.

3.Shunt, Hall Current Sensor

Failures: Abnormal sampling, inaccurate power reading, frequent protective shutdown.

4.Water Cooling Fittings, Water Pipes, Water Pump (Liquid‑cooled Chargers)

 Failures: Water leakage, abnormal water circulation, high module temperature.

Causes: Hose aging, seal failure, water pump wear.

5.Insulation Monitoring, BMS Communication Module (Main Control Board)

Failures: Insulation alarm, handshake failure, communication disconnection.

Causes: Damaged electronic components.

6.Auxiliary Power Supply

Failures: No power supply to the display screen and main board.

Causes: Power supply burnout.

III. Wearing Parts Exclusive to AC Chargers

AC chargers have a much lower overall failure rate than DC chargers.

1. AC charging gun and cable
2. Internal relays and terminal blocks (heating and oxidation)
3. Damage to low-voltage power supply sub-modules on the main board

On-site Troubleshooting Sequence (From Simple to Complex)

1. First check: charging gun, cooling fan, circuit breaker, surge protective device
2. Next check: contactor, door lock, display and indicator lights
3. Advanced inspection for DC chargers: capacitors, sensors, communication / insulation modules
4. Final maintenance: power module (high-cost, major repair level)

Summary

This document only covers hardware operation and maintenance and does not involve software. While hardware shall comply with national standards uniformly, software logic and fault codes vary among manufacturers, which will therefore not be elaborated.