AC vs DC Charging

• AC charging uses your car's onboard charger to convert AC to DC. It's slower and best for home or work charging.
• DC charging converts power inside the charger and sends DC straight to the battery. It's much faster and best when you're in a hurry.

Support with Amber

Amber for EVs supports AC charging and is working on supporting DC charging as part of our Vehicle to Grid project.

If you have a DC charger at home and a compatible EV - Amber for EVs will not work as expected.

How it actually works

Your EV battery runs on DC. The difference between AC and DC charging is just where the AC to DC conversion happens.

AC charging:

• Power from the grid arrives as AC.
• Your car's onboard charger converts it to DC.
• The car’s onboard charger has a maximum rate (e.g. 7, 11, or 22 kW), which caps your charging speed.

DC charging (fast charging):

• The charger converts AC to DC.
• DC is delivered directly to the battery.
• Because the charger hardware is larger (and often higher voltage/current), DC charging can be much faster, though the car also has its own DC charge limit.

Typical use cases

AC charging is best for:

• Overnight home charging
• Workplace charging
• Anywhere you’ll be parked for hours

DC charging is best for:

• Road trips / highway charging
• Fast top-ups when you’re time constrained
• Doing V2H and V2G charging at home

Speed: what to expect

Charging speed depends on the EV, charger, temperature, and battery state of charge — but as a rule of thumb:

• AC (home/work): 3.6-22 kW
• DC (public fast chargers): 25-350 kW, vehicle-dependent

Even at a 350 kW site, your EV may only draw 80–170 kW, and usually only for part of the session.

Why DC charging slows down (“tapering”)

DC fast charging tapers as the battery fills to protect the battery and manage heat. Charging is typically fastest between roughly 10-60% and slows down beyond that. This is normal and varies by vehicle.

Connector basics

What you see on the plug isn’t always the whole story, but common patterns are:

• AC charging: typically a Type 2 connector
• DC fast charging: typically a CCS2 connector (often looks like Type 2 with two extra pins at the bottom)

Some vehicles and chargers may also support CHAdeMO, though it’s less common in new deployments.

FAQs

Does AC vs DC affect battery health?

Occasional DC fast charging is fine for most drivers. Frequent fast charging can increase heat and may contribute to faster degradation over time, depending on the EV and usage patterns.

Is DC always faster?

Generally yes, but not always — a slow DC charger (e.g. 25 kW) can be similar to or only a bit faster than strong AC (11–22 kW), depending on the car.