Understanding AC and DC Charging

How does it work?

Most rapid charging works slightly differently to regular charging to accommodate for the greater amount of power being transferred.

Fast and slow charging is done through alternating current (AC). With AC charging, the vehicle receives the power from the charger and converts it to direct current (DC) for usage. It does this using what is referred to as its “on board charger” which is really just a converter.

A minority of rapid chargers still use AC and are able to provide power rates of up to 43kWh.

Most rapid chargers use direct current charging instead. With DC charging, the conversion from AC to DC is done in the charger instead of the vehicle. This means the charger can feed power straight to the vehicle’s battery without the need for conversion. This is what allows for greater power rates and faster charging.

Top Tip

DC charging is more common than you think. The plug charging your mobile phone automatically converts AC power to DC for faster charging.

Types of plug for rapid charging

Since most rapid charging uses DC, the type of plug used to connect to the vehicle is slightly different to the ones used in AC charging.

You can’t use your standard Type 1 or Type 2 inlets used in AC charging. Instead CHAdeMO (short for Charge de Move) or CCS (Combined Charging System) inlets are used as standard. CHAdeMO inlets are typically used by Asian manufacturers and CCS by European manufacturers. However, as with Type 1 and Type 2 inlets, this is not always true.

CCS inlets are attached to the bottom of the regular Type 1 or 2 inlet on the vehicle. The CHAdeMO plug requires its own separate inlet which means the vehicle has to have a larger charge port area.

Not all vehicles come with these extra inlets as they aren’t all compatible with rapid charging.

Top Tip

The minority of rapid chargers that use AC don’t require any extra inlet to facilitate higher power rates and uses the Type 2 inlet as standard.

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