July 27, 2023
AC vs DC charging
In the context of electric vehicle (EV) charging, AC and DC refer to Alternating Current and Direct Current. These are two types of electrical current, and they're used differently in EV charging.
AC vs DC charging
Table of contents

What is the difference between AC and DC charging?

  • AC Charging (Alternating Current): Most home and public charging points use AC charging. This is because the electricity grid supplies AC power. When an EV is charged using AC power, the car's onboard charger converts the AC power to DC power, which can be stored in the battery. AC charging is typically slower than DC charging. Standard home chargers in the UK, often known as Level 2 chargers, typically deliver 3.6 kW or 7 kW of power, though some can deliver up to 22 kW.
  • DC Charging (Direct Current): Some public charging stations, known as fast-charging or rapid-charging stations, use DC charging. With DC charging, the power conversion happens in the charging station, which allows the power to go directly into the car's battery. This makes DC charging much faster than AC charging. DC chargers start at around 50 kW of power, but newer ones can deliver 150 kW or even 350 kW. However, not all electric vehicles can accept these higher power levels.
When you're charging at home, you'll generally be using AC charging. DC charging stations are more commonly found at public charging locations like motorway service stations, where they can provide a quick top-up of power to extend your range during a long drive.

So DC charging is better?

Whether Direct Current (DC) charging is "better" than Alternating Current (AC) charging depends on your specific needs and circumstances. Here are a few points to consider:

Advantages of DC Charging

  • Faster Charging Times: The main advantage of DC charging is that it's much faster than AC charging. This can be especially beneficial on long trips where you need to recharge quickly to get back on the road.
  • Convenient for Long Distance Travel: If you're traveling a long distance and need a quick recharge to continue your journey, DC fast charging stations, often found at motorway service stations, can be incredibly useful.

Considerations with DC Charging

  • Potential Battery Wear: Frequently using DC fast charging can potentially lead to faster degradation of the battery over time, especially if the battery is frequently charged to its maximum capacity. It's often recommended to use DC fast charging sparingly and stick to AC charging for regular, daily use.
  • Higher Cost: DC fast charging is often more expensive than AC charging. This is especially true at public charging stations where you pay per kWh of electricity, as they often charge a premium for the faster charging speed.
  • Availability: While the network is growing, DC fast chargers are not as widespread as AC chargers. Most home and workplace chargers use AC due to the high cost and power requirements of DC chargers.
In conclusion, DC fast charging is a great option when you need to charge your EV quickly, such as on a long road trip. However, for everyday charging, especially at home, AC charging is typically more cost-effective and gentler on the battery over the long term. So, it's not necessarily that one is better than the other, they're just better suited to different situations.

How do I know if my car can support DC charging?

Whether your electric vehicle (EV) can support Direct Current (DC) fast charging depends on its make and model, and the type of charging system it uses. Here are a few ways to determine this:
  • ClearWatt Vehicle Directory: Use our directory of electric vehicles to see if your vehicle has DC charging.
  • Check the Owner's Manual: The simplest way to determine whether your EV can support DC fast charging is to check your vehicle's owner's manual or manufacturer's specifications. They will specify the types of charging that your vehicle can handle.
  • Check the Charging Port: Another way is to look at the charging port on your vehicle. In the UK, if your car supports DC fast charging, it will likely have a Combined Charging System (CCS) connector. The CCS connector has two additional pins below the standard Type 2 connector, which are used for DC charging.
  • Ask the Dealer or Manufacturer: If you're still unsure, you can always ask your vehicle's dealer or contact the manufacturer's customer support for assistance.
Remember, even if your vehicle supports DC fast charging, not all charging stations provide this type of charging, and using fast chargers can be more expensive than slower AC charging. DC fast charging is typically used for long trips where you need to charge quickly, while slower AC charging is often sufficient for daily use and overnight charging at home.

How do I know if a charger is using AC or DC charging?

Whether a charger is using Alternating Current (AC) or Direct Current (DC) is typically indicated by the charging station itself, and also by the type of connector the charging station uses.
Here are some things to look for:
  • Charging Rate and Naming Convention: Usually, the naming convention or the rate of charge can provide an indication. For instance, Level 1 and Level 2 chargers are AC chargers. Level 3, also often referred to as "fast" or "rapid" charging, typically refers to DC charging.
  • Connector Type: The type of connector can also be a giveaway. In the UK, for example, a Type 2 connector is used for AC charging, while CCS (Combined Charging System) connectors are used for DC fast charging.
  • Charging Station Description: Information about the charger type should be clearly labelled on the charging station itself or in the charging network's mobile app or website if one is available. DC fast chargers are often marketed as such due to their speed advantage.
Remember, not all electric vehicles can use all types of chargers. Use our vehicle directory to check which types of chargers are compatible with your vehicle. If you're in doubt, it's best to check with the manufacturer or the charging network.
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