Charging dwell time is the total time a vehicle remains parked at a charging location, whether it is actively charging or not. It is a key operational metric because it determines the appropriate charging type (AC vs. DC), influences charger utilization, and strongly affects charge throughput and site economics.
What Is Charging Dwell Time?
Dwell time includes:
– Time plugged in and actively charging
– Time plugged in but not charging (finished, paused, waiting for load management)
– Time parked in the bay without charging (blocking/ICEing, if tracked)
Dwell time is different from “charging time” because it includes non-charging occupancy.
Why Charging Dwell Time Matters in EV Charging
Dwell time shapes how charging infrastructure should be designed and operated. It matters because it:
– Determines charger power requirements (long dwell supports AC, short dwell needs DC)
– Drives bay turnover and congestion at public sites
– Impacts utilization metrics and can hide inefficiencies (high occupancy, low kWh)
– Affects pricing strategy (idle fees, parking fees, time-based tariffs)
– Influences site sizing and charging capacity planning
– Impacts fleet readiness when vehicles must depart by fixed times
In many sites, managing dwell time is the fastest way to improve performance without adding hardware.
How Dwell Time Is Measured
Operators measure dwell time using CPMS and site data:
– Plug-in timestamp to unplug timestamp (connector occupancy)
– Charging start to charging end (active charging duration)
– Difference between occupancy and charging time (idle time)
– Optional: bay occupancy sensors to detect parked-but-not-plugged-in vehicles
For accurate operational KPIs, dwell time is often tracked per connector and per bay.
Typical Dwell Time Patterns by Site Type
Common patterns include:
– Workplace charging
– Long dwell (6–9 hours), good fit for AC and smart load sharing
– Residential charging
– Very long dwell (overnight), often managed with scheduling and low-to-mid power AC
– Retail and leisure destinations
– Medium dwell (1–3 hours), often served by AC or moderate DC depending on customer expectation
– Highway and transit hubs
– Short dwell (10–40 minutes), typically needs DC fast charging and strong throughput focus
– Fleet depots
– Controlled dwell windows based on shifts, ideal for scheduled charging and load management
How Dwell Time Affects Site Performance
Dwell time is strongly linked to:
– Charge throughput
– Long dwell with low delivered energy reduces throughput per bay
– Charger utilization rate
– High occupancy can inflate “utilization” if it includes idle plugged-in time
– Congestion and queues
– Long dwell or “charging to 100%” at DC sites increases queue probability
– Pricing and enforcement strategy
– Idle fee policy and parking rules directly shape dwell behavior
– Load management behavior
– Smart charging can increase dwell time (charging delayed) but still meet readiness targets if planned correctly
Typical Use Cases
– Choosing AC vs DC for a new site based on expected dwell time
– Setting time limits and idle fees for public charging bays
– Fleet planning to ensure vehicles are charged before departure while minimizing peaks
– Workplace fairness policies (session limits, rotation rules)
– Diagnosing low throughput sites caused by long idle occupancy
Key Benefits of Managing Dwell Time
– Higher site throughput without adding chargers
– Better user experience through reduced queues
– More predictable fleet readiness outcomes
– Improved ROI by increasing energy delivered per bay-hour
– Better alignment between charger power level and real user behavior
– Reduced operational friction and support complaints
Limitations to Consider
– Dwell time is partly driven by site purpose; not all dwell can or should be reduced
– Idle fees must be designed carefully to avoid customer backlash or unfair penalties
– Some users need longer sessions due to vehicle limits (charge acceptance rate, tapering)
– Tracking accuracy depends on reliable session and occupancy data
– Enforcement may require physical measures or agreements with site owners
Related Glossary Terms
Charger Utilization
Charger Utilization Rate
Charge Throughput
Idle Fee Policy
Bay Occupancy Sensors
Charging Capacity Planning
Charge Tapering
Charge Acceptance Rate
Load Management
Fleet Depot Charging