AC or DC Charging

There are two types of electricity supply and two types of charger. These are alternating current (AC) and direct current (DC).

There are advantages and disadvantages to both charger types. To help you make the best decision for your application, we’ve explained the differences below.

Two Types of Current

Before diving into the differences between charger types, it’s worth gaining and understanding of the differences between AC and DC.


AC is the type of power transmitted by the National Grid and what comes out of our plug sockets at home.

The direction of the charge changes periodically hence the name alternating current. In the UK, this change in direction happens 50 times per second.

The National Grid uses AC because it can be transmitted over long distances with fewer energy losses then if using DC.


Direct current is unidirectional. This means that the flow of charge always goes in the same direction. DC is the type of electricity used in many home appliances and in all devices with batteries. The charger that you plug into the wall for your phone or laptop contains a convertor that converts the plug sockets AC into DC suitable for your phones battery.

AC Chargers for Electric Vehicles

Alternating Current chargers are currently more commonly found then DC chargers. This is in part due to their lower cost and simpler installation.

Chargers rated as “slow” or “fast” will almost always use AC.

To change the AC into the DC required by a battery, EV’s use an inbuilt convertor. This is often referred to as the “onboard charger”.

DC Chargers for Electric Vehicles

The key difference between AC and DC chargers is the location of the power convertor.  DC chargers convert the National Grid’s AC power into DC before it enters the vehicle. The current then flows directly into the EV’s battery, bypassing the inbuilt convertor. This arrangement allows for increased charging speeds when compared with AC chargers. The downside, is that DC chargers are significantly more expensive than AC chargers. For this reason, DC chargers are best suited to locations where rapid charging is essential, e.g motorway service stations. 

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