OCPP Charger Telemetry: Interface Protocols for EV Charging Grids

The OCPP Standard in Modern EV Grids

Deploying electric vehicle (EV) charging infrastructure requires standardized telemetry. The Open Charge Point Protocol (OCPP) governs communication between Charge Point Operators (CPOs) and Central Management Systems (CMS). Telemetry grids track charger availability, transaction logs, and power grid loads. Standardizing on OCPP 1.6 or 2.0.1 allows charging networks to scale rapidly, supporting multiple charger manufacturers without interface friction.

SQL Schema for Charger Session Telemetry

To analyze charger performance and power consumption, CMS databases must record every charging session's telemetry metrics. The following SQL table logs OCPP transactions:

CREATE TABLE ocpp_session_telemetry (
  session_id VARCHAR(64) PRIMARY KEY,
  connector_id INT NOT NULL,
  charge_point_id VARCHAR(64) NOT NULL,
  start_meter_value INT NOT NULL,
  current_power_kw DECIMAL(6, 2) NOT NULL,
  battery_soc_percent INT,
  updated_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
);

This structure supports real-time monitoring of energy consumption across EV charging grids.

Optimizing Polling Intervals and Diagnostics

CPOs manage network congestion by setting a 10s recommended polling interval for charger state updates. Fast polling allows operators to detect grid imbalances and trigger automatic cooling protocols. Implementing these real-time telemetry checkpoints improves system health, yielding up to a 15% savings in maintenance costs by preventing connector overheating and grid failures.

OCPP WebSocket Handshake JSON Payload

OCPP communication occurs over WebSocket connections. When a charger connects to the CMS, it exchanges boot notification messages containing status and diagnostic specifications:

{
  "message_type": "BootNotification",
  "charge_point_vendor": "GridCharge India",
  "charge_point_model": "GC-Fast-120",
  "firmware_version": "v3.2.1-build88",
  "status": "Accepted",
  "current_time": "2026-07-02T09:17:36Z",
  "heartbeat_interval": 300
}

This configuration establishes the telemetry connection, achieving a 99.9% connection uptime.

Indian Standards and Grid Safety Guidelines

EV charging networks in India must follow the Bureau of Indian Standards (BIS) IS 17017 guidelines. These regulations mandate specific safety standards, including earth leakage checks and automated isolation circuits. CPOs run continuous telemetry diagnostics to ensure safety systems comply with Central Electricity Authority (CEA) norms, securing charger grids against grid overloads.

OCPP Meter Values Logs and Charging Session Parameters

EV smart grids communicate with charging terminals using the open-source OCPP protocol. The charging terminal sends real-time meter value reports mapping active current, voltage, and energy consumption metrics. The central server logs this data to track grid load.

When a session finishes, the billing engine calculates transaction costs based on active energy consumption parameters. Storing these transaction metrics in secure databases ensures billing records are accurate and transparent.