EV Charging Time Calculator
Estimate time to reach a target battery charge level.
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What this tool does
Estimate time to reach a target battery charge level. Use average charging power, not peak advertised power. Charging taper and temperature can extend actual time.
How to use the EV Charging Time Calculator
- Enter or select battery capacity (kwh).
- Enter or select starting charge (%).
- Enter or select target charge (%).
- Enter or select average charger power (kw).
- Enter or select charging efficiency (%).
- Read the calculated result; change any measurement to compare alternatives.
Formula
hours=battery×(target−start)/100/(average power×efficiency/100)
- battery
- Battery capacity (kWh)
- start
- Starting charge (%)
- target
- Target charge (%)
- power
- Average charger power (kW)
- efficiency
- Charging efficiency (%)
Use average charging power, not peak advertised power. Charging taper and temperature can extend actual time.
Worked example
For ev charging time calculator, the following measurements illustrate the exact method: Battery capacity (kWh): 75; Starting charge (%): 20; Target charge (%): 80; Average charger power (kW): 7.2; Charging efficiency (%): 90.
Inputs
- Battery capacity (kWh)75
- Starting charge (%)20
- Target charge (%)80
- Average charger power (kW)7.2
- Charging efficiency (%)90
Result
- Estimated charging time (hours)6.94
Results explained
- Estimated charging time (hours)
- Estimated charging time (hours) from the formula above. Use average charging power, not peak advertised power. Charging taper and temperature can extend actual time.
Frequently asked questions
hours=battery×(target−start)/100/(average power×efficiency/100)
Use average charging power, not peak advertised power. Charging taper and temperature can extend actual time.
No. Electrical and HVAC results are estimates. Installation must comply with local codes and be checked by a qualified licensed professional.
Nameplate values, conductor temperature, power factor, efficiency, weather and actual installation conditions may differ from your entered assumptions.
Confirm units, manufacturer data and the formula's assumptions, then verify sizing with the equipment instructions and applicable local standards.