Every EV battery stores direct current, and every grid supply delivers alternating current, so a conversion has to happen somewhere. That placement is the whole technical difference: AC charging leaves the conversion to a converter inside the car, while DC charging moves it into the station and feeds the battery DC directly. Who sets the limit, what the connector looks like and how fast the system can scale all follow from that decision.
Key Takeaways
- The technical difference is one fact: AC charging converts in the car, DC charging converts in the station.
- On AC, the car’s onboard charger is the ceiling; on DC, station and battery negotiate the limit continuously.
- DC connectors add a dedicated high-current path, so DC cables are built differently.
- DC scales because the converter is bought once per station, not once per car.
One Battery, Two Places to Convert
An AC charger is, technically, a supervised supply point. It delivers grid AC, watches for faults, and tells the car the maximum current it may draw; the car’s onboard charger then rectifies that AC into DC. A DC charger contains the rectifier itself: its power electronics convert grid AC to controlled DC and deliver it straight to the battery. Our explainer Are EV Chargers AC or DC? gives the short version; the table below is the technical one.
| Technical point | AC charging | DC charging |
|---|---|---|
| Where AC becomes DC | In the car, in the onboard charger | In the station’s power electronics |
| What crosses the connector | Grid AC, plus a signalling channel | Controlled DC, plus a data channel |
| Hard limit on session power | The car’s onboard charger, however strong the post | The station’s converter and the battery’s acceptance, whichever is lower |
| Typical band (U.S. DOT) | Level 2: 7–19 kW | DC fast: 50–350 kW |
What the Placement Does to Control
Because the converter sits in the car, AC charging is negotiated in one direction. The charge point advertises a current ceiling, and the onboard charger decides how much to use; a car with a small onboard charger on a high-output wallbox still charges at the car’s limit.
DC charging reverses the relationship. The station’s converter does the work, so car and station hold a continuous data conversation: the battery management system states what it will accept as conditions change, and the station regulates its output to match, moment by moment. That is why a DC session slows as the battery fills — the battery asks for less, and the station obeys. The two even signal differently: AC relies on a simple pilot signal, DC on digital communication over the cable.
What It Does to the Connector and Cable
The connector records the split in metal. An AC inlet needs pins for AC power and signalling only. A DC inlet adds a high-current DC path — on CCS connectors, two large DC pins sit below the AC section, which is why a CCS plug looks like a J1772 or Type 2 plug with an extra block underneath.
Cable design follows the current. A DC cable must carry the station’s rated current for a whole session, which is why DC cables are shorter, thicker and heavier than AC cables — and why the highest-power designs cool the cable itself.
Why DC Scales and AC Plateaus
AC charging plateaus because the converter rides in every car. Making it bigger adds cost, weight and heat to a vehicle that uses it a few hours a day, so onboard chargers stay sized for overnight dwell times. DC charging scales because the converter is bought once, in the station, and shared by every car that visits. The U.S. DOT’s bands reflect that logic — Level 2 at 7–19 kW, DC fast charging at 50–350 kW.
The Same Split in the EVDANCE Range
EVDANCE builds on both sides of the line. The EV-ACT5006T is an AC wall charger, up to 48 A hard-wired or on a NEMA 14-50P — it supplies AC, and the car’s onboard charger sets the session limit. The EV-RHDC30K-L is a compact DC charger at 22 kW with OCPP 1.6J and an IP54 enclosure: conversion happens in the unit, so the battery’s acceptance governs the session. The full range is on the products page.
Frequently Asked Questions
Does a battery ever charge on AC directly?
No. A traction battery stores and releases DC. AC charging does not avoid conversion — it relocates it into the car.
Is DC charging just stronger AC charging?
No. The current type, the converting hardware, the control relationship and the connector all differ. A DC charger is a different equipment class, not a wallbox turned up.
Can an AC charger be upgraded to DC later?
No. There is no shared conversion hardware to upgrade — the DC unit’s power electronics are the product. Sites that need both install both, or replace the unit.
Related Reading
- Are EV Chargers AC or DC?
- How Do DC Fast Chargers Work?
- Level 1 vs Level 2 vs DC Fast Charging: A Practical Comparison
- How Do Home EV Chargers Work?
