What Is DC Fast Charging and How Does It Work?

What Is DC Fast Charging and How Does It Work?

DC refers to “Direct Current” – the type of power that the battery actually requires. However, most electric vehicle chargers use AC (alternating current) power to replenish batteries. Batteries do not accept AC Power, so all EVs have a converter or rectifier onboard. It changes the AC power into the DC power needed to charge EV batteries. When there’s no conversion, vehicles experience fast DC charging.

Why does AC charging take so long?

Whenever you feed AC Power into your EV, the convertor gets to work and changes it into the DC power your batteries need. The acceptance rate of this convertor, which varies by manufacturer,  impacts the charging speed and time needed to charge an EV. This process requires an additional task to complete, so the AC-fueled charging speed is relatively slow. All Level 2 charging stations rated between 7 kW and 22 kW use AC power from the power station, so they depend on the rectifier to convert it into DC. 

Left to Right: AC to DC chargers showing a variety of sizes and speeds.


DC power, on the other hand, bypasses the converter altogether so the charge can go directly into the battery. This speeds up the charging process, which is why it’s called fast or rapid charging. Compared to charging with AC power, using DC power for charging is very fast. DC charging offers advantages in situations where quick battery replenishment is either required or preferred. The only limiting factor here is the connector type used to charge the vehicle.

DC chargers come in a rang of sizes. Those with lower kilowatt (kW) offerings may be able to charge up to around 50 kW while the fastest chargers go up to 180 or 360 kW. Not many consumer cars right now can accept that much power, so it’s good to know about your own vehicle. 


Well, there are a few reasons why that might not be the best option.

First, it depends on the connector type. Every EV has a max acceptance rate for power. In simple terms, there is a max amount of AC power that the EV will be able to convert to DC. Additionally, there is a max DC power the EV can accept at once. Fast DC chargers use two types of connectors: CCS or CHAdeMO connectors. Tesla uses its own proprietary Type 2 – 120 kW DC connector.

Second, fast charging is good only occasionally. The fast charging rate heats up the battery, which can be bad for batteries. Consequently, regular rapid charging may degrade your EV batteries in the long term.

Third, fast DC charging is the most expensive. As is requires high voltage and amperage, the cost of electricity is higher. Also, since this is the fastest way of charging at any public station, you will be charged a higher rate for this kind of charging.

So we hope you now know what DC fast charging is and how it works. You should also now know why the speed of AC home chargers is slower. Next time you want to top up your EV batteries, you will be able to make an informed choice based on your situation. Choose wisely, and save yourself time and money!

Learn More about

DC Charging

The Noodoe EV Exceed DC chargers are the fastest, highest performing DC chargers in the industry. Through Noodoe technological innovation, our Exceed DC  level 3 chargers offer 20% faster performance at the same price point, an incredible value for money. Choose from 60 kW, 120 kW, or 180 kW chargers.