Home charger power
VehiclesHow fast can you charge your car at home?
Phases, amps and volts to charging power and the time to add the energy you need.
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More options
Charging power
11 kW
Adds about 11 kWh per hour. 40 kWh takes 3 hrs, 37 mins.
3 × 230 V × 16 A = 11.04 kW. A qualified electrician decides the installation, cable and fuses.
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Phases, amps and volts to charging power and the time to add the energy you need.
How to use
- Choose single-phase or three-phase and enter the current per phase: the wallbox setting, or the rating of the circuit breaker feeding it.
- Check the voltage per phase (230 V in most of Europe, 240 V in North America) and enter the energy you want to add to the battery.
- Read the charging power and the time. If your car's onboard charger is slower, enter its limit under More options.
Charging power by circuit at 230 V, and the time to add 50 kWh
| Current (A) | Phases | Power (kW) | Time for 50 kWh |
|---|---|---|---|
| 6 | 1 | 1.38 | 1 day, 12 hrs, 14 mins |
| 10 | 1 | 2.3 | 21 hrs, 44 mins |
| 16 | 1 | 3.68 | 13 hrs, 35 mins |
| 32 | 1 | 7.36 | 6 hrs, 48 mins |
| 16 | 3 | 11.04 | 4 hrs, 32 mins |
| 32 | 3 | 22.08 | 2 hrs, 16 mins |
Ideal values without charging losses and without a limit from the car's onboard charger.
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How it works
AC charging power is set by the circuit and the car, whichever is lower. A home wallbox only supplies alternating current; the car's onboard charger converts it for the battery. A three-phase circuit carries three times the power of a single phase with the same current.
Power = phases × voltage per phase × current. Three phases at 230 V and 16 A give 3 × 230 × 16 = 11,040 W, about 11 kW; a single phase at 230 V and 32 A gives 7.36 kW. The 230 V per phase is the same as 400 V between phases in the three-phase 230/400 V system (IEC 60038); North America uses 120/240 V (ANSI C84.1). Time = energy ÷ power: 40 kWh at 11.04 kW takes about 3 h 37 min.
This is a formula, not an electrical design. The fuse of the whole house, the cable, the other loads and load management decide how much current you may actually draw, and an installation must be done and approved by a qualified electrician. Losses in the cable, charger and battery make real charging a little slower and are not included.
Worked example
How long does it take to add 40 kWh with 3 phases at 230 V and 16 A?
- 3 × 230 V × 16 A = 11.04 kW.
- 40 kWh ÷ 11.04 kW = 3 hrs, 37 mins.
3 hrs, 37 mins
Frequently asked questions
How many kW is a 16 A three-phase charger?
About 11 kW: 3 phases × 230 V × 16 A = 11.04 kW. Most cars charge at up to 11 kW on AC; some accept only 7.4 kW.
How long does it take to charge an electric car at home?
Divide the energy you need by the charging power. Adding 40 kWh at 11 kW takes about 3.6 hours, at 7.4 kW about 5.4 hours and from a 2.3 kW household socket about 17 hours.
Why does my car charge slower than my wallbox?
The car's onboard charger sets a limit. A car with a 7.4 kW onboard charger on a three-phase 11 kW wallbox still charges at 7.4 kW. Enter the limit under More options to see this.
Is it safe to use a higher current?
Only if the whole installation is designed for it. Charging is a long, steady load, so the cable, the breaker and the main fuse of the house must all carry it together with everything else that is on. Ask a qualified electrician; this calculator cannot judge it.
What is load management?
It lowers the charging current when other appliances use a lot of power, so the main fuse is not overloaded. It is set up in the wallbox or the home energy system by an electrician.
Which voltage should I enter?
The voltage per phase: 230 V in Europe, also for three-phase supplies (400 V between phases). In North America a home charger uses 240 V on one phase, or 120 V for a plain socket.
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