DC Fast Charging Explained
- AC charging is easy to find, since the electrical grid is AC. The necessary conversion for the EV battery, which is DC, is done by a converter on board of the EV. All that is needed, external to the car, is equipment that controls and monitors the process, and assures the adequate protections. However, the on-board converter is limited in power for reasons of cost, space and weight, making the process usually take several hours to recharge your car.
- DC fast charging (also know as Level 3 charging), on the contrary, connects directly to the car’s battery, allowing the off-board equipment to have any power needed. DC charging is capable of charging to 80% the electric vehicle’s battery in less than 20 minutes for most cars, making the EV charging process much faster than the normal charging process.
- DC fast charging is therefore essential for drivers and fleets to be able to use their cars without the fear of running out of energy, as they can easily recharge in a small break, when wanted or needed.
- DC fast charging stations provide a high power DC current, generally up to 120 kW, to the electric vehicle’s battery without passing through any onboard AC/DC converter, which means the current is connected directly to the battery. Most cars today can only use up to 50kW, so that is for most cases the maximum power that is being installed.
New cars coming out will have the ability to charge at greater rates of power. As EVs come with higher range, and batteries get bigger, DC charging solutions are being developed to support long range EV batteries through ultra fast charging stations up to 350 kW or more.
Currently, there are three types of DC fast charging: CHAdeMO, Combined Charging System (CCS) and Tesla Supercharger.
Multi standard DC charging solutions are able to charge any CCS or CHAdeMO EV, and even a Tesla, when using the CHAdeMO adapter.
The Combined Charging System (CCS) is based on open and universal standards for electric vehicles. The CCS combines single-phase with rapid three-phase charging using alternating current at a maximum of 43 kilowatts (kW), as well as direct-current charging at a maximum of 200 kW and the future perspective of up to 350 kW – all in a single system.
The CCS includes the connector and inlet combination as well as all the control functions. It also manages communications between the electric vehicle and the infrastructure. As a result, it provides a solution to all charging requirements.
CHAdeMO is an association that is open to every organization that works for the realization of electro mobility. The Association, established in Japan, now has hundreds of members from around the globe. In Europe, CHAdeMO members based in the branch office in Paris, France, actively reach out to and work with the European members.
Going beyond the borders of industrial segments, CHAdeMO provides a platform for a variety of stakeholders including: charger manufacturers, automakers, utility companies, charging station operators, municipalities, certification bodies and non-profit organizations (NPOs.)
Tesla vehicles use an onboard charger to convert alternating current (AC) from a wall charger to direct current (DC) that’s stored in the battery. Superchargers consist of multiple chargers working in parallel to deliver up to 120 kW of power directly to the battery. As the battery nears a full charge, the vehicle’s onboard computer gradually reduces the current to the optimum level for topping off cells.