Two of the most important parts of an electric vehicle are the electric motor & the battery. The electric motor in the EV is powered by the battery. There are mainly two ways to charge the battery: AC charging & DC charging. AC stands for ‘Alternating Current’ and DC stands for ‘Direct Current’. Batteries store DC power. With a DC charger, the current can flow directly into the battery. With an AC charger, the current has to be converted to DC first. When it comes to electric vehicles, there is a ‘converter’ inside the car. It is known as an ‘onboard charger’ though it really is just a converter. It converts power from AC to DC and then transfers it to the car’s battery.
The difference between AC & DC charging basically lies in the location where the AC power gets converted, whether it’s inside or outside the car. Unlike AC chargers, a DC charger has the converter inside the charger itself. That means it can transfer power directly to the car’s battery and doesn’t need the onboard charger to convert it.
AC charging is ideal for charging your car at home or at work. DC charging is more common near highways or at public charging stations, where you don’t have much time to recharge.
We get AC power from the grid and this is converted into DC power so it can be stored in batteries.
The main advantage of AC chargers is that they are affordable. The disadvantage of AC charging is that it is slower. However, the technology is still improving and today an AC charging station can provide up to 22 kWh of charging power. More on this below.
AC DC charging station is technologically much more complex and many times more expensive than an AC charger.
However, slow charging is gentler on the batteries and it helps in increasing its life, so the ideal strategy should be to charge via the AC charger at home and use DC charging stations only during long journeys or when you are in a hurry.
DC fast charging is essential for long distance driving and for large fleets. The quick charging enables drivers to recharge on a small break as opposed to being plugged-in overnight.
Level 1, 2 & 3 Charging:
Level 1 & Level 2 charging is AC charging. Level 1 charging is basically the standard household outlet. Level 1 charging generally takes 8 to 12 hours to completely charge a fully depleted battery. Level 2 charging generally takes 4 to 6 hours to completely charge a fully depleted battery.
Level 3 charging is DC charging. Also known as DC fast-charging, it provides an 80% charge in 30 minutes.
The best of both worlds: AC Fast Charging
Common knowledge says that AC charging is slow and DC is fast, but there’s a bit more to it than that. Technological advancements have increased Level 2 output and a concept known as AC fast-charging has emerged. The best example of this is a wallbox charger that you can get installed at home. Wallbox chargers are often seen as a good option for Plug-in Hybrid Electric Vehicles (PHEVs), which have both an internal combustion engine and an electric motor, because their smaller batteries take less time to charge. Level 2 AC ‘fast’ chargers are also found at public charging stations. Their output power ranges from 3.3 kW to 7 kW to 22 kW. The disadvantage of AC charging stations is that they are not that common and slower compared to DC stations. However, the technology is still improving and today an AC charging station can provide up to 22 kW of charging power. For example, if an electric car has a 21 kWh battery, it can be fully charged in about an hour.