This is a very common question from people who are new to Electric Vehicles (EVs). While there are plenty of great articles explaining AC vs DC charging in detail (for example: https://www.evnex.com/articles/ev-charging-times), a simple way to think of it is that DC power is ready to use and AC power needs to be converted to DC before it can be used by your EV.
As a simple analogy, let’s say that ice (not to be confused with Internal Combustion Engine!) is the way fuel is stored in your EVs battery. So if you want to recharge your battery you need frozen water. Now there are 2 ways you can get frozen water:
- Start with water and freeze it (eg: convert the water to ice via freezing)
- Use pre-made ice (eg: the water is already frozen)
The first example is similar to AC power. It needs to be converted to DC before it can be stored in the battery of your EV. This is why AC charging is slower. The AC power (water) needs to be converted to DC power (ice) before it can be stored in the battery.
The second example is similar to DC power. It is ready to be used immediately. No conversion is required. Therefore DC charging is much faster.
This analogy also extends to the associated costs of AC vs DC charging. As a general rule, AC charging is cheaper (often “free”) and DC charging is generally more expensive. For example, charging at home is usually AC, and you can make use of things like off-peak electricity and rooftop solar to bring your charging costs down. Many of the public AC chargers (for example in shopping centres and car parks) are even free to use. On the other hand, most DC chargers are pay-per-use because you are paying for the convenience of quick charging.