This calculator measures how intensively a bidirectional vehicle-to-grid charger is used during a reporting period. It separates connection time from active charging or discharging time and reports both utilization and idle connected time.
Operators can use it to compare sites, identify scheduling bottlenecks, and estimate whether a charger is mostly productive or simply occupied. The metric is time-based and does not measure energy throughput or financial return.
1. Count chargers
Include only chargers available during the same reporting window.
2. Set the reporting hours
For a 30-day month, a continuously available charger has 720 hours.
3. Total active V2G time
Sum charging and discharging hours across all chargers.
4. Total connected time
Include all plugged-in hours, whether active or idle.
5. Compare the utilization rates
A large gap between connection and active utilization indicates substantial idle occupancy.
Active utilization shows the share of total charger capacity spent transferring energy.
Planned outages should be removed from available hours if the goal is operational rather than calendar utilization.
Given: 4 chargers, 720 hours, 900 active hours, and 1,600 connected hours.
Calculation: Available hours = 4 × 720 = 2,880. Active utilization = 900 ÷ 2,880 × 100 = 31.25%. Connection utilization = 55.56%. Idle connected hours = 700.
Result: Active utilization is 31.3%, with 700 connected but inactive hours.
Yes. Count any period when the charger is transferring energy in either direction.
No. If it does, the charger count, reporting hours, or aggregated usage data are inconsistent.
Subtract verified unavailable hours when measuring operational utilization. Keep them included when measuring utilization against total calendar capacity.
Vehicles occupy chargers for long periods without transferring energy, which may point to scheduling, authorization, or grid constraints.
No. It measures time usage, not kilowatt-hours transferred or conversion efficiency.