EV Charging
Fundamentals

What's the difference between AC and DC?

The are two different types of charging in electric vehicles. They're known as alternating current (AC) and direct current (DC) power.

AC charging for electric vehicles

Within each electric vehicle, there is a converter built inside the car. It's known as the "onboard charger", converting power from AC to DC and then feeding it into the car's battery. This is the most common charging method for electric vehicles, with most residential and commercial chargers using AC power supply.

DC charging for electric vehicles

The difference between AC charging and DC charging is the location where the AC power is getting converted; either inside or outside the car. Unlike a typical AC charger, DC chargers have the converter built inside of them. That means it can feed power directly into the car's battery, bypassing the need for the onboard charger to convert it. DC chargers are typically bigger and faster, and have been a breakthrough for charging sites around New Zealand. 

Charging Speeds for AC and DC Chargers

 Type Charging Time Power Rating
 AC 6-10 hours 7-22kW
DC 20-30 minutes  50-350kW

The actual charging times taken to charge a vehicle battery will be

The electric vehicles battery capacity
The current state-of-charge on the vehicles battery
The capacity of the charging supply point