This estimator calculates the charging time required for a fleet of electric vehicles based on total energy demand and the charging capacity available at a depot. It accounts for the number of vehicles, energy needed per vehicle, charger count, charger power, simultaneous-use limits, and charging efficiency.
Fleet managers can use the result to check whether an overnight or shift-change window is long enough and to compare charger deployment options. The estimate assumes energy can be distributed efficiently among vehicles; dispatch sequencing, charger faults, tapering, and vehicle-specific power limits may extend actual completion time.
1. Enter fleet size
Count vehicles that must be charged in the window.
2. Enter energy per vehicle
Use the average battery energy each vehicle needs.
3. Add available chargers
Count chargers that can serve the fleet.
4. Set charger power
Use delivered power per charger before efficiency losses.
5. Limit simultaneous operation
Apply the site or load-management limit.
6. Review completion time
Compare the result with the available depot window.
Total battery energy = Vehicles × Energy needed per vehicle
Active chargers = min(Vehicles, Available chargers, Simultaneous limit)
Effective site power = Active chargers × Charger power × Efficiency
Fleet charging time = Total battery energy ÷ Effective site power
The main result is the continuous charging time needed to deliver the fleet’s total requested battery energy.
The model assumes balanced charger use and does not include vehicle movement or queuing delays.
Given: 20 vehicles, 45 kWh each, 10 chargers, 19.2 kW per charger, 10 simultaneous chargers, and 90% efficiency.
Calculation: Total battery energy = 20 × 45 = 900 kWh. Active chargers = min(20, 10, 10) = 10. Effective site power = 10 × 19.2 × 0.90 = 172.8 kW. Time = 900 ÷ 172.8 = 5.208 hours.
Result: Estimated fleet charging time = 5 hours 12 minutes.
At least two charging waves are required because 20 vehicles share 10 chargers.
The calculator uses an average per vehicle. For mixed needs, enter total energy divided by vehicle count or run separate groups.
It is the largest number of chargers the site can operate at once after electrical-capacity or load-management constraints.
Not explicitly. For high state-of-charge targets or DC fast charging, reduce the effective power assumption or add operational buffer.
Manual movement and connection time are excluded. Add that time separately when multiple waves share the same chargers.
Yes. Compare the estimated hours with the actual window and retain margin for late arrivals, faults, and dispatch changes.