With cold temperatures in winter and with the installation of faster charging stations, a lot of questions are being asked about electric vehicle charging times with fast chargers:
• What are the charging times for different vehicle models with the various fast chargers?
• At what battery charge level does the charging slow down to the point where it is better to stop charging?
• Do low temperatures influence charging speeds?
• Does a 100-kW charging station provide a much faster charge than a 50-kW charging station?
Factors that influence charging times
The charging power of an electric vehicle (EV) plugged into a DC fast charge (DCFC) station is indicated in kilowatts (kW). An EV charging at 40 kW will accumulate 20 kWh in half an hour, which provides around 100 km of range. In the case of another EV that charges at 20 kW, it would take an hour to accumulate the same 20 kWh of energy. This other car charges twice as slowly, because it has half the charging power of the first car.
The charging speed depends largely on two factors: the characteristics of the vehicle battery and the type of charging station used. Regarding this second point, the Electric Circuit has three main types of charging stations: 25-kW, 50-kW and 100-kW stations. These numbers indicate the maximum amount of power that can be supplied by the charging station. Thus, with a 50-kW station, the charge rate is 50 kW or less.
However, the charging speed is mainly influenced by the vehicle battery performance. A Battery Management System (BMS) built into the vehicle communicates with the charging station and adapts the charging power according to the battery charge level and temperature. Thus, the vehicle determines the amount of power supplied by the station, in order to protect the battery.
On this page, the “optimal charging curve” for a vehicle type and DCFC type is the maximum charging speed when the battery temperature is optimal.
• When the battery charge level is close to 80%, the charging power requested by the vehicle begins to drop rapidly; in other words, the charge slows down. As charging is billed by time, it becomes more expensive and takes longer. It is therefore preferable to stop the charge before it is complete, even if this means having to charge more often.
• The ideal battery temperature is between 20°C and 25°C. This is why the charging power will be lower when the weather is very hot or when the weather is cold.
• The charging speed of certain vehicles is clearly more sensitive to cold temperatures.
Presentation of data sheets
The data sheets indicate the charging power of each vehicle model according to the following parameters:
• Battery charge level (0 to 100%)
• Battery temperature
The battery temperature is not always indicated on the vehicle dashboard and is not known to the Electric Circuit. We have therefore defined:
• The optimal winter charging curve (grey curve for 50-kW charging stations and black curve for 100-kW charging stations; the curve thickness represents slight power variations among identical vehicles for the same charge level).
• The maximum charging curve (curve without thickness) for vehicles whose charging power is very sensitive to battery temperature.
We have also defined other curves that represent the charge level when the battery is too cold and takes time to warm up while charging. (Warm-weather data will be provided in summer 2021.)
Information improvement process
These curves have been established based on data from hundreds of charges made up to December 2020. Nevertheless, it is possible that specific cases may not have been taken into account. If the charging curves you observe with Electric Circuit stations are different, please email firstname.lastname@example.org and specify the charging station number, the specific date of your charge and your vehicle model. With your help, we’ll be able to keep this information up to date.
Audi – e-tron
BMW – i3
Chevrolet – Bolt
Chevrolet – Spark
Ford – Focus
Ford – Mustang
Harley Davidson - Limewire
Hyundai – Ionic
Hyundai – Kona
Kia – Niro
Kia – Soul
Nissan – Leaf
Tesla –Model 3, Model S, Model X
Volkswagen – e-Golf