Electric car charger time: models comparison and how to calculate

Your electric car charger time depends on some factors. The U.S. average for Level 1 chargers is about 40-50 hours to charging an EV, but it depends in your case. At the end of this Hourglass article, check a table with 30 EV models and their charging times.

How long it takes to charge an electric car? All about it

If you have no idea how to answer some of these questions don’t worry, the goal of this Hourglass article is to give you the conditions to estimate the charging time and answer these questions. So be sure to read all the way to the end.

Charging current

There are two main types of current for charging an electric vehicle: direct current (DC) and alternating current (AC).

Grid power is always provided in alternating current by the utility company, while batteries can generally only store energy in direct current.

This is why most electronics have a converter, including cell phones.

In this case, the conversion from alternating current to charge the cell phone is the responsibility of the charger, which has a small converter in the plug that goes into the outlet.

With electric cars it is no different.

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There is an inverter that converts alternating current from the grid into direct current to power the battery.

The inverter, or converter, is located inside the vehicle and is commonly called an integrated inverter or onboard charger.

This is currently the most common method of charging electric vehicles, and most chargers use alternating current for charging.

As stated earlier, grid power is always available in alternating current.

The difference between AC and DC charging is where the energy to charge the battery is converted: inside or outside the car.

Unlike the AC charger, the DC charger has its own inverter inside. This means that it can feed the vehicle battery directly, without having to go through the on-board charger to convert the current.

Because of this, DC chargers are faster than AC chargers.

Type of power grid

The type of power grid also influences the charging time.

Depending on the available mains voltage, the charging power can vary, and consequently the charging time can vary.

To find out what is the mains voltage of your home or business, just check with your electrician.

The vast majority of chargers work on 220 V, so there are three possible types of low voltage supply for charging the electric vehicle.

Single-phase 127 V or 220 V (F + N + T) with one phase, one neutral, and one ground

The charger normally operates on 220 V, so if the single-phase supply is 127 V, you will need to fit an autotransformer to raise the voltage to 220 V.

Biphasic 220 V (2F + T) with two phases and a ground.

This is the input voltage that most chargers work with.

Three-phase 220 V or 380 V (3F + N + T) with 3 phases, a neutral and a ground.

In 3-phase mode, the charger normally works on 380 V, so if the 3-phase supply is 220 V, you will need to put an autotransformer to raise the voltage from 220 V to 380 V.

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Cable Power

The power available in the cable is a little considered but also important factor, especially for alternating current (AC) charging, because just as the power in the electrical grid can be two-phase or three-phase, the cables follow the same pattern.

The same type of cable can be found in different phases and different powers, and this directly influences the charging time.

This is because AC charging always ends up being limited by the lowest power, be it the charger, the integrated AC/DC inverter, or the cable. To find out the maximum power of the cable, just check with the manufacturer.

For example, cables with a standard Type 1 connector (SAE J1772) can charge up to a maximum power of 7.4 kW, while some cables with a standard Type 2 connector (IEC 62196) can charge up to 22 kW.

A very common question is how much power is available in the cable.

When they say that the cable can charge up to a certain power, all lower powers are also covered, i.e. a cable of up to 22 kW can charge the vehicle at 3.7 kW, 7.4 kW, 11 kW, and 22 kW.

But remember that charging is always limited by the lowest power, whether it is the car’s inverter, charger, or cable.

Onboard charger or AC/DC inverter integrated in the electric car

As we mentioned before, this equipment which is inside the vehicle and is responsible for converting the alternating current from the electric grid into direct current to feed the battery.

It is common for people to believe that the charger used for charging the electric car is the only factor that defines the total charging power and consequently the recharging time, but in AC charging, the power of the AC/DC inverter integrated in the car also influences the calculation.

The higher the power of this converter, the greater its weight and size. This is the main reason why most electric cars still come with a low-power AC/DC converter.

Most electric cars have an integrated single-phase – low power – inverter. So even if you buy a powerful charger connected to the three-phase grid, with a three-phase cable, if the inverter in the vehicle is single-phase – up to 7.4 kW, the charging time will be limited by the lower power, in this case single-phase.

To find out the power of the integrated inverter of an electric vehicle, just consult the manufacturer or technical manual of the car.

Battery capacity

The energy storage capacity that the battery supports (measured in kWh) is another factor that influences the recharging time.

As with cell phones, the higher the capacity of the battery, the longer it will take to charge completely, if the same cable is used.

To get the battery capacity information for an electric vehicle, you can find it in the technical specification/manual or ask the vehicle manufacturer. The capacity usually ranges from 24 to 90 kWh.

Whatever the battery size, it is not possible to compare vehicles with different battery capacities.

This question seems simple and obvious, but it is common to find reports comparing electric vehicles without taking this difference in size into account.

Another important point is to know the state of charge of the battery (full vs. empty). If the battery is totally discharged, it will take longer to recharge compared to a battery that is half charged.

To find out the current battery level, cars show this information in percent and in kWh on the digital display on the vehicle’s dashboard.

As an example, to charge an electric car with a capacity of 24 kWh that is at 70% of the level, it will be necessary to charge only 7.2 kWh of the 24 kWh that the battery has.

If the same car is at 20% charge, it would need to charge 19.2 kWh of the 24 kWh.

Charging power

As discussed in the previous topics, the charging power will depend on several factors.

In the case of direct current (DC) charging, the power available at the electric station is higher than the power found in residential and commercial chargers, making the recharging time shorter, about less than 1 hour to complete the vehicle battery.

In the case of alternating current (AC) charging, factors such as the power of the converter integrated into the EV, cable, charger, and type of grid can influence the charging time. But generally, a charging system with higher power output will charge the vehicle in a shorter time.

These factors will define the charging time.

Charger power

Every charger has a maximum power that will be transferred from the grid to the vehicle. AC chargers can generally charge from 3.7 kW to 22 kW, while DC chargers can handle up to 350 kW.

Total charging power

As discussed in the previous topics, the total charging power will depend on a combination of a number of factors.

In the case of alternating current (AC) charging, the power of the integrated inverter and charger, combined with the type of grid and the type of cable will determine the charging time.
Remember that whoever has the lowest power in the combination will limit charging. However, generally a system with higher power makes it possible to charge the vehicle in less time.

In the case of direct current (DC) charging, since the power available at the electric station is greater than that found in residential and commercial chargers, coupled with the fact that it does not need to go through the vehicle’s inverter, the recharging time ends up being much shorter – about less than an hour to complete the vehicle’s battery.

Recharging time

According to the U.S. Departament of Transportation, the average time for electric cars chargin is around 40-50 hours. One way to estimate the time without taking all factors into consideration is to use only the power of the charger and the size of the battery.

The calculation is done by dividing the battery capacity by the charging power:

Charging time (hours) = battery capacity (kWh) / charging power (kW).

For example, an electric car with a 24 kWh battery, with a charging power of 3.7 kW, will take around 7 hours to have the battery fully charged.

In the case of the same car mentioned above, but using an 11 kW charger, it would take less than 3 hours to have the battery full. The image below shows the time variation of the examples cited according to the charging power.

However, just like recharging electronics, charging is not linear and there is a certain variation in time, especially between 80% and 100%, where the charging speed is slowed down in order to optimize the performance of the battery and prolong its life.

Electric car charger time table: 30 models comparison

Now that you know how to calculate it depending on your specific case, you can check this table with the average from each model, with it’s different battery sizes and levels.