EV charging time calculator

Use our electric car charging time calculators to estimate the EV charging time. How long does it take to charge an electric car? It depends on the car make, model, year, version and which charging station you use.

EV Charging Time Calculator – Home Charging

1. How to estimate the charging time:

Charging power = EV charger power rating x Voltage /1,000

Charging time = Battery capacity x (Target charge level – Current charge level) / (Charging power x 0.9);

  • if charging power >= acceptance rate of the on-board charger,

Charging time = Battery capacity x (Target charge level – Current charge level) / (acceptance rate x 0.9)

The 0.9 is the average power efficiency.

2. Example (2021 Tesla Model 3 Standard Range Plus):

  • When EV charger power rating is 16 amps,

Charging power = 16 amps x 240 volts / 1,000 =3.84 kW < 7.6 kW

Charging time = 50 kWh x (0.8-0.1) /(3.84 kW x 0.9) = 10 hours 8 minutes

  • When EV charger power rating is 48 amps,

Charging power = 48 amps x 240 volts / 1,000 =11.52 kW > 7.6 kW

Charging time = 50 kWh x (0.8-0.1) /(7.6 kW x 0.9) = 5 hours 8 minutes

1. How to estimate the charging time:

Efficiency = Driving range / Battery capacity

Charging power = EV charger power rating x Voltage /1,000

  • If charging power < acceptance rate of the on-board charger,

Charging time = Desired distance / (Efficiency x Charging power x0.9);

  • if charging power >= acceptance rate of the on-board charger,

Charging time = Desired distance / (Efficiency x Acceptance rate x0.9)

The 0.9 is the average power efficiency.

2. Example (2021 Tesla Model 3 Standard Range Plus):

  • When EV charger power rating is 16 amps,

Charging power = 16 amps x 240 volts / 1,000 =3.84 kW < 7.6 kW

Charging time = 30 miles / (5.26 miles/kWh x 3.84 kW x0.9) = 1 hour 40 minutes

  • When EV charger power rating is 48 amps,

Charging power = 48 amps x 240 volts / 1,000 =11.52 kW > 7.6 kW

Charging time = 30 miles / (5.26 miles/kWh x 7.6 kW x0.9) = 51 minutes

1. How to estimate the range per hour of charging (RPH):

Efficiency = Driving range / Battery capacity

  • If charging power < acceptance rate of the on-board charger,

RPH (Range per hour) = Efficiency x Charging time x Charging power x0.9

  • if charging power >= acceptance rate of the on-board charger,

RPH (Range per hour) = Efficiency x Charging Time x Acceptance rate x0.9

The 0.9 is the average power efficiency.

2. Example (2021 Tesla Model 3 Standard Range Plus):

Efficiency = 263 miles / 50 kWh = 5.26 miles/kWh

  • When EV charger power rating is 16 amps,

Charging power = 16 amps x 240 volts / 1,000 =3.84 kW < 7.6 kW

RPH = 5.26 miles/kWh x 1 h x 3.84 kW x 0.9 = 18.2 miles

  • When EV charger power rating is 48 amps,

Charging power = 48 amps x 240 volts / 1,000 =11.52 kW > 7.6 kW

RPH = 5.26 miles/kWh x 1 h x 7.6 kW x 0.9 = 36.0 miles

EV Charging Time Calculator – Public Fast Charging

1. How to estimate the charging time:

Charging time = Battery capacity x (Target charge level – Current charge level) / (Charging power x 0.9)

The 0.9 is the average power efficiency.

 

2. Example (2021 Tesla Model 3 Standard Range Plus):

Charging time = 50 kWh x (0.8-0.1) / (150 kW x 0.9) = 16 minutes

1. How to estimate the charging time:

Efficiency = Driving range / Battery capacity

RPH (Ranges per hour) = Efficiency x Charging power x0.9

Charging time = Desired distance / RPH

 

2. Example (2021 Tesla Model 3 Standard Range Plus):

Efficiency = 263 miles / 50 kWh = 5.26 miles/kWh

RPH = 5.26 miles/kWh x 150 kW x 0.9 = 710.1 miles/h

Charging time = 30 miles / 710.1 miles/h = 3 minutes

Example: Tesla Model 3 Standard Range Plus (2021)

Battery Capacity: 50 kWh | Driving Range: 263 miles (EPA) | Acceptance Rate of the On-Board Charger: 7.6 kW | Supercharging Max: 170 kW | Efficiency = Driving range / Battery capacity =263 miles / 50 kWh = 5.26 miles/kWh | Current Charge Level: 10% | Target Charge Level: 80% | Desired Distance: 30 miles | Charging Power on a DC Fast Charger: 150 kW

Electricity & Electric Vehicle Charging Basics

 

Electricity Basics

There are two primary terms in the electric car industry – kW (kilowatts) and kWh (kilowatt hours). Kilo means 1,000, and so kW means 1,000 watts.

kW – kW is a rate of power, which tells us how much energy per second an item will demand in order to work. You can figure how much power (kW) can be delivered to your electric car when you use an EV charger with a known amp rating. The calculated formula is

kW = (amps x volts) / 1,000.

kWh – kWh is a measurement of energy, which is how much power is demanded over an amount of time.

Energy equals power (kW) multiplied by time (h).

Electric Vehicle Charging Basics

 

Charging Terms 

  • Battery Capacity – Battery capacity or the size of the battery is how much stored energy a battery has and is measured in kWh.
  • Charging Power – Charging power determines the rate of charging and is measured in kW. For a home EV charger, you can know the charging power if you know the amps that the charger delivers:

Charging power (kW) = Current (amps) x Voltage (volts) /1,000

For a public fast charger, the charging power is given in kW directly.

  • Charging Rate – When you are talking about the charging speed of an EV charger, charging power (kW or amps) is used to get a sense of how fast or slow the charge will take.

When you are talking about specific cars, range per hour (RPH) can be used to express the charging rate of an electric car. It highly depends on the car, and it’s easy to understand for most people.

Typically, electric vehicle manufacturers list the battery capacity (kWh) and the driving range (miles) of each EV on the specifications. So you can get the efficiency, and the formula is:

Efficiency (miles/kWh) = Driving range (miles) / Battery capacity (kWh).

So

RPH (miles/h) = Efficiency (miles/kWh) x Charging power (kW).

Other Considerations 

  • Battery capacity, Driving range, Acceptance rate of the on-board charger can be obtained from your EV’s manual or the manufacturer’s official website.
  • Current charge level – It’s the level of the battery at the current state.
  • Target charge level – It’s the level of the battery that you prefer.

NOTE: All results are calculated based on the theoretical assumptions, and may vary under different circumstances in real life.

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