Remote EV Charger Diagnostics: Fix Before the Truck Rolls

The OCPP StatusNotification carries an errorCode field that most CMS platforms treat as a string to display. It's actually a structured classification: GroundFailure, OverCurrent, PowerMeterFailure, OverVoltage, UnderVoltage, WeakSignal, ConnectorLockFailure and more.

Each of those has a distinct root-cause set. GroundFailure with a transient RCD trip is one thing; GroundFailure that clears and re-fires within seconds is another. Reading the pattern matters more than reading the code.

Session failure diagnostics start by classifying where the fault originated. Grid-side: brownouts, voltage sags, phase loss. Charger-side: relay wear, RCD faults, comms drops. Vehicle-side: incompatible EV, damaged connector on the car, driver aborted.

The intelligence layer classifies these automatically from the telemetry pattern. A field technician arriving at a site with the diagnosis pre-classified spends 20 minutes verifying instead of an hour investigating.

Meter drift is a quiet failure mode: no error code, no alert, just a slow divergence between energy billed and energy actually delivered. Anomaly detection on session-level energy-per-minute versus fleet baseline catches this before it becomes months of revenue leakage.

Same technique catches theft (unusually short sessions with high energy), stuck sessions (energy accumulating with no vehicle plugged in per StatusNotification), and cases where a charger reports session complete but the meter kept running.

• Last 30 minutes of raw telemetry
• OCPP StatusNotification history with error codes
• Voltage and current readings from meter values
• Connector temperature trend
• Last successful session, with SoC, duration and energy

• Soft reset of the charger
• Hard reset via OCPP Reset message
• Configuration push to correct a bad parameter
• Firmware rollback to a known-good version
• Connector unlock command
• Local authorization list refresh

• Burnt or fused connector contacts
• Physical relay failure or welded contacts
• RCD hardware fault beyond software reset
• Cable damage or vandalism
• Earthing issue at the site
• Water ingress or physical damage to the enclosure