Telemetry streaming is the continuous or near-real-time delivery of operational data from EV charging assets and related systems to a backend platform, data lake, or monitoring tool. Instead of periodic batch reports, telemetry streaming sends events and measurements as they occur—enabling live dashboards, alerts, and automated control decisions.
In EV charging, telemetry streaming can include charger status events, session updates, power measurements, fault codes, and connectivity health signals.
Why Telemetry Streaming Matters in EV Charging
Streaming telemetry enables faster response and better optimization:
– Detect outages and faults quickly, improving charger uptime
– Reduce MTTR by providing richer diagnostics and time-stamped events
– Support real-time load management and demand limit enforcement
– Improve customer experience with accurate live availability data
– Enable operational analytics (utilization, queueing, peak events) without delays
– Provide a stronger audit trail for billing, compliance, and dispute handling
For high-utilization public sites and fleet depots, streaming is often critical for reliability.
What Data Is Commonly Streamed
Telemetry streaming typically includes:
Charger and Connector Status
– Available / occupied / charging / faulted / offline states
– Connector-level status (useful for multi-socket units)
– Session start/stop events and reasons (user stop, EV stop, error)
– Authorization events (RFID/app/card)
Power and Energy Measurements
– Instantaneous power (kW) and current/voltage readings
– Cumulative energy delivered (kWh) during a session
– Site load measurements from meters or CT clamps (for maximum site demand limit)
– Temperature and internal diagnostics where supported
Faults and Maintenance Signals
– Alarm codes and error categories
– Ground fault / RCD events (where reported)
– Door open / tamper detection events (where installed)
– Communications quality (signal strength, reconnects, latency)
Commercial and User Signals (Platform-Dependent)
– Tariff applied, pricing events, idle fee triggers
– Payment status events for tap-to-pay workflows (where integrated)
How Telemetry Streaming Is Implemented
Common implementation patterns include:
– Charger-to-backend messaging via charging protocols (often OCPP)
– MQTT, WebSockets, or event streaming gateways for high-frequency data
– Edge gateways that aggregate multiple chargers and push telemetry upstream
– Streaming into data platforms (message buses, event hubs) for processing and storage
– Real-time rules engines for alerts and automated actions
Some telemetry is event-based (state changes), while other telemetry is periodic (power samples every X seconds).
Telemetry Streaming vs Periodic Reporting
– Telemetry streaming supports real-time operations: alerts, live availability, fast diagnostics
– Periodic reporting supports accounting and summaries: monthly energy totals, invoice reconciliation
Most operators use both: streaming for operations and batch for finance and compliance.
Design Considerations and Common Pitfalls
– Data volume: high-frequency sampling can create cost and noise without clear value
– Time synchronization: inconsistent timestamps break session analytics and billing reconciliation
– Connectivity: poor LTE or firewall policies can cause gaps and false alarms
– Data model consistency: stable IDs for site/charger/connector are essential
– Alert fatigue: too many low-quality alerts increase OPEX and reduce trust
– Security: streaming channels must be authenticated, encrypted, and access-controlled
Best Practices
– Stream event changes and key measurements; sample high-frequency data only when needed
– Use clear severity levels and escalation rules for faults
– Combine charger telemetry with metering data for validation (sub-metering)
– Include health metrics (heartbeat, signal quality) to detect “silent failures”
– Build dashboards that drill down from site → charger → connector → event timeline
Related Glossary Terms
OCPP
Charger Uptime
Mean Time To Repair (MTTR)
Load Management
Maximum Site Demand Limit
Sub-metering
Tamper Detection
Tariffs
Sustainability Dashboards