Nowadays, electric vehicles are becoming more and more common on the streets due to government financial incentives, efforts in promoting EV charging standards, mandates and codes. However many people don’t know how to calculate the time to charge the electric vehicle.
Formula to calculate the time of charging:
The time taken to charge an electric vehicle range from less than 30 minutes or more than 12 hours. This mainly depends on the capacity of the battery and the speed (power) of the ev charger. We have a simple formula to calculate the time: Time of Recharging=Battery Capacity/ EV Charger Power. For example, if you have a Nissan LEAF (2018) whose battery capacity is 40kWh, it will take about 11 hours (40kWh/ 3.7kW) to charge with a 3.7kW charger. While with a 50kW rapid charging point, it only takes about 1 hour to charge this Nissan LEAF. In conclusion, the bigger your car’s battery capacity and the slower the ev charger, the longer it will take to charge the car from empty to full.
Factors affecting ev charging speed:
There are 5 main factors affecting the time needed to charge an electric vehicle.
Capacity of battery: The bigger your vehicle’s battery capacity (in kWh), the longer it will take to recharge your electric car.
Battery status (empty or full): If you need to charge the ev from empty, it will take longer time to charge than if you top up the electric car from 40%.
Max charging rate of the vehicle: You can only charge an ev’s battery at the maximum charging rate allowed for the vehicle. For example, if your electric vehicle’s max charge rate is 11kW, you won’t be able to charge it any faster by using a 22kW ev charger.
Max charging rate of the charger: The time it takes to charge an ev will also be limited by the max charging rate of the charger you will use. For example, even if the electric vehicle allows for a charging rate of 11kW per hour, it will only charge at 7kW on a 7kW charger.
Environmental factors: The colder the ambient temperature, the longer it will take to charge the electric car. It is particularly true when you are using a rapid chargepoint. Colder temperatures also mean that electric vehicles are less efficient, so fewer miles are added per charging compared with ev charging in warm or hot weathers.
Although fast charging is preferred, it protects the ev battery to charge with slow chargers.