What’s the Difference Between AC and DC Charging?

AC and DC. These two terms are always mentioned when you read up about electric car charging. So, what are they? And how are they different? Let’s find out!

And no… these abbreviations don’t refer to the American rock band… 

AC and DC Charging for Electric Vehicles

The two electric vehicle charging terms refer to Alternating Current (AC) and Direct Current (DC) charging. 

Source: Ampcontrol.io

The term AC describes the electrical current’s flow of charge, which alternates and periodically changes direction. On the other hand, DC power always moves in a straight line.

Charging with an AC Charger

Source: ComfortDelGro

By default, the power that comes from the grid is dispensed in AC. However, batteries like the one found in your EV can only store power as DC. 

Therefore, the power from the AC charger has to flow through the onboard charger before going to the traction battery. As the conversion will take some time, and there might be some limitations to the power output of your onboard charger, AC charging will usually take a longer time to power up your car.

Charging with a DC Charger

When you charge your electric vehicle with a DC charger (also known as Fast or Rapid Chargers), it bypasses all of the limitations of the onboard charger and required conversion. Instead, it provides DC power directly to the battery, therefore charging speed has the potential to be greatly increased.

However, it’s also important to note that charging times are dependent on the battery size, the output of the charger, as well as many other factors. Nonetheless, it’s safe to say that many electric vehicles will be able to power up to 80% charge in about an hour with the current DC fast chargers on the market.

The Importance of a High Voltage Onboard Charger

Onboard chargers have their own rating, typically below 10kW. This means that the onboard charger will only be able to receive 10kW of power from the charger at a go. 

In other words, if you’re charging your electric vehicle with a 22kW external charger, you’ll only receive power at the rate of 10kW at a time. This is the maximum speed your electric vehicle will charge at.

With an onboard charger that has a higher rating, like the BYD e6’s class-leading 40kW onboard charger, charging times will be quicker as you’ll be able to receive more power from AC chargers.

This is why it’s important to choose an electric vehicle that not only has a good battery range, but also a high voltage onboard charger.

If you’re in the market for an electric car, you should definitely consider the BYD e6 — the most affordable EV in Singapore right now. 

The BYD e6 takes just 40mins to charge from 20% to 80% on a DC charger, and just 1 hour on an AC charger, which is significantly faster than many other EVs.