How Long Will It Take To Charge My EV?

It can be daunting getting up to speed with electric cars and the lingo that comes with them. In this article we unpack the different charging technologies and explain how they influence charging time.

Rob Speirs Evnex
Rob Speirs | GM Sales & Marketing
An EV Charging in the street

There are two main factors that determine how fast your electric vehicle will charge, firstly the speed of the charging station, but also the maximum supported charging speed of the EV itself.

There are several different types of charging technology:

  • DC chargers are most suitable for public charging and will provide a rapid charge experience.
  • AC chargers like the Evnex R-Series are typically used for destination charging (locations like home or work). They take longer to charge an EV and are being best suited for long parking periods.
  • Portable charging leads plug into a household socket and provide the slowest charging experience. They are generally not recommended for every day use, as they rely on the integrity of the wiring in your home, which is not always suited for the high power demands and long charging times that are typical of modern EVs.

AC & DC charging stations come in different sizes:

  • DC chargers typically range from 25kW to 350kW. In New Zealand, most are 50kW.
  • Fixed AC chargers range from 3.7kW to 22kW, with single phase 7.4kW being the most common in New Zealand.

How does my electric car’s onboard charger influence my charging speed?

It is important to understand that with DC charging, energy is fed directly from the charging station into the vehicle's battery. On the contrary, AC charging requires the car to convert the AC to DC before being stored in the battery. Therefore, when charging from an AC charger, the charging speed is constrained by the size of the car’s on-board charger, even though the AC charging station may be capable of charging at a higher speed.

As an example, you may have a three phase 22kW AC wall charger installed, but your car can only convert a maximum of 6.6kW on a single phase via the on-board charger. Therefore, the highest charging speed you will see is 6.6kW. Although it may seem unnecessary to install a charging station with a higher capacity than your vehicle supports, it can make sense in public locations or for future proofing purposes.

A diagram of different EV charging types
AC charging stations require the vehicle's internal on-board charger to convert from AC to DC. DC charging stations feed DC directly into the battery.

When planning to buy a charger for your electric car, it’s helpful to understand the maximum charging speed of your car. You can safely install a charging station with a higher power rating than your car supports, but you won’t get be able to get the full benefit (until you potentially upgrade your EV in the future). If you are unsure about your EV, refer to this guide which can help you to understand the different plug types and charging capabilities.

The table below provides a guide to charging times. The larger the EV's battery and the slower the charger, the longer it will take to charge.

Type Of Charger Speed Range Added Per Hour Charging Time
8 Amp Portable Charger 1.8kW 10km 35 hours
AC Charger Single-phase 7.4kW 40km 9 hours
AC Charger Three-phase 22kW 120km 3 hours
DC Charger Medium 25kW 150km 1.5 hours (to 80%)
DC Charger Rapid 50kW 300km 1 hour (to 80%)
DC Charger Ultra Rapid 175kW 1000km 15 minutes (to 80%)

* The information in the above table is approximate and based on a vehicle with a 64kWh battery. Note that only some EVs will accept higher delivery speeds from ultra rapid chargers.

You may note that for DC chargers, we refer to the charging time as the time to reach 80%. This is because the charging rate usually decreases significantly towards the end of the charge. If you're using a DC charger during a long trip, generally you'll only charge to around 80%, as you'll see diminishing returns as you approach 100%. It's generally considered good etiquette as well if there are others waiting to use the charger.

"There are two main factors that determine how fast your electric vehicle will charge, firstly the speed of the charging station, but also the maximum supported charging speed of the EV itself."

Glossary

AC - Alternating Current; this is the type of electricity you use in your home.

DC - Direct Current; this is the type of electricity used when charging or consuming energy from a battery.

kW - Kilowatt; a unit of measurement for electrical power. For example, a Generation 2 Nissan Leaf can produce a maximum of around 80kW of power.

kWh - Kilowatt-hour; a unit of electrical energy. If an appliance uses 2kW of power for an hour, then it is said to have used ‘2kWh’ of electricity. Typical electric car batteries range from 24kWh to 100kWh.

Rob Speirs Evnex
Rob Speirs | GM Sales & Marketing