Uptime is the percentage of time an EV charger is available and able to deliver a successful charging session when a driver attempts to use it. It is one of the most important operational KPIs for charge point operators (CPOs), fleets, and site owners because it directly impacts user trust, utilisation, and revenue.
What Is Uptime?
Uptime measures charger availability over a defined period (day, month, year).
– High uptime means the charger is operational, connected, and capable of charging
– Low uptime means the charger is out of service due to faults, maintenance, power loss, connectivity issues, or site restrictions
Uptime can be measured at different levels:
– Charger uptime (the whole unit is available)
– Connector uptime (one port works while another may be down)
– Network uptime (the charger is online and communicating with the CPMS)
Why Uptime Matters in EV Charging
Uptime is directly linked to charging network performance.
– Impacts driver confidence and repeat usage, especially for public charging
– Drives EV charging revenue and ROI by enabling more successful sessions
– Reduces support workload by preventing repeated failed attempts
– Supports funding and tender requirements that specify minimum availability targets
– Improves fleet readiness by ensuring vehicles can charge reliably before departures
For public accessibility charging, uptime is often a contractual KPI with penalties or service-level commitments.
How Uptime Is Measured
Uptime measurement depends on how “available” is defined.
Common methods include:
– Status-based uptime: the charger reports “Available” vs “Faulted/Unavailable” via OCPP
– Session success rate: uptime inferred from successful vs failed charging attempts
– Connectivity-based uptime: whether the charger is online and reporting to the CPMS
High-quality reporting often combines these:
– OCPP status + error codes
– Session outcomes and user attempts
– Exclusions for planned maintenance windows (if defined in the SLA)
Common Causes of Downtime
– Grid power loss, breaker trips, or site electrical faults
– Connector wear, cable damage, or mechanical impact
– Communication failures (SIM/network issues, router problems)
– Software bugs or failed firmware updates
– Payment terminal or authorization failures
– Environmental issues (water ingress, condensation, overheating)
Downtime can be reduced significantly through good installation practices, preventive maintenance, and fast incident response.
How Operators Improve Uptime
– Proactive monitoring and alerting in the CPMS
– Integrated support workflows such as integrated ticketing
– Remote actions (reboot, remote reset, configuration checks)
– Preventive maintenance based on usage (connector cycles, lifetime energy delivery)
– Robust installation: correct earthing, bonding, protection devices, and cable routing
– Secure, staged firmware updates using a secure update pipeline
– Spare parts strategy for high-wear components (connectors, contactors, screens)
Key Benefits of High Uptime
– Higher utilisation and more kWh delivered per charger
– Better user satisfaction and network reputation
– Stronger revenue performance and faster CAPEX recovery
– Lower operational cost per successful charging session
– Better compliance with public contracts, grants, and SLAs
Limitations to Consider
– Uptime alone does not guarantee good user experience (a charger can be “available” but slow or hard to access)
– Measuring uptime requires consistent definitions (connector vs charger, exclusions, planned maintenance)
– Site factors like parking enforcement and physical access can reduce “practical uptime” even if the charger is technically online
– Multi-vendor networks may report status differently without careful normalization
Related Glossary Terms
Charger Uptime Benchmarks
Charger Diagnostics
Integrated Ticketing
Charging Session
Charging Availability Anxiety
kWh Delivered per Charger
Lifetime Energy Delivery
Secure Update Pipeline