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EV charging

What Is an Onboard Charger?

An onboard charger, or OBC, is the EV component that converts AC electricity from a home or public AC charger into DC electricity for the battery.

Last reviewed: October 1, 2026CarGlossary Phase 2 P1 glossary
Simple definition

The onboard charger is the car's AC-to-DC charging hardware. It sets the maximum AC charging rate the vehicle can accept.

AC charging vs DC fast charging

Home wallboxes and many public chargers provide AC electricity. The onboard charger converts that AC into DC that the battery can store.

DC fast chargers work differently. They convert power outside the vehicle and feed DC power to the battery system, so the onboard charger is usually bypassed during DC fast charging.

Why onboard charger rating matters

If a car has an 11 kW onboard charger, connecting it to a 22 kW AC charger will not make the car accept 22 kW. The car's OBC, the charging cable, electrical supply, phase support and software limits all matter.

This is the AC version of a broader rule: the charging station rating is not always the same as the vehicle's actual charging power.

Does the OBC affect DC fast charging?

Usually no. DC fast charging depends more on the battery pack, BMS, connector, thermal system, voltage architecture and charging curve.

For DC topics, see CCS charging, NACS charging and 800V architecture.

Onboard chargers and bidirectional power

Some bidirectional charging systems require power electronics that can move energy out of the vehicle as well as into it. Depending on the design, this may involve onboard hardware, offboard hardware or both.

Always check whether the vehicle supports bidirectional charging and which use cases are enabled.

What to check before buying

  • Maximum AC charging power.
  • Single-phase or three-phase support in your market.
  • Whether the supplied cable supports the same current.
  • Home electrical capacity and installation limits.
  • Whether DC charging speed is being confused with AC charging speed.
CCS chargingNACS chargingPlug and Charge800V architectureC-rate chargingBidirectional charging

Sources

CarGlossary note:

Feature names, connector support, diagnostic behavior and EV specifications can vary by model year, trim, software version and market. Always verify the exact vehicle documentation before buying, repairing or relying on a feature.