DC charging is the most effective way of powering an electric vehicle battery. Scientists and engineers have made incredible progress. A new generation of DS fast chargers allow even faster recharges of up to 80% of total capacity in less than an hour.  

 AC v DC – why DC wins for fleets 

Passenger and light commercial vehicles use an AC charger plugged into the mains. AC power is transferred to an onboard charger that transforms this to the DC charge required by the battery. 

 The solution is cost-effective, small, and lightweight, but it is slow – taking hours to fully recharge a battery. 

In contrast, DC chargers deliver power directly to the battery – ensuring a much faster charge. As a result, DC charging is an optimal solution for fleet operators who want to maximise their vehicles' operational capacity.  

DC charging technology is continuing to evolve. First-generation DC chargers were limited to 50kW, but newer vehicles can accept much larger charge rates  some, cases up to 270kW. 

Couple this with larger batteries fitted to commercial vehicles, and the benefits are clear.  

DC charging means vehicles can spend more time on the road and less time being charged. As a result, they're powering a cleaner tomorrow for us all. 

What are the main DC charging methods? 

There are several DC charging methods currently used to charge fleet vehicles, including conductive charging and wireless charging: 

Conductive charging  Conductive charging works through a manual connection from the vehicle to the charging station. The current flows through a cable (or from a pantograph to a wire), enabling rapid recharging rates with high transfer efficiency. It's the cheapest hardware solution, but it needs manual involvement to work. The transfer of power is one-way, from the charger to the vehicle. Conductive charging can deliver up to 400kW with a CCS Type-2 connector. However, MW chargers are just around the corner and will make charging times even faster. 

Wireless DC charging – Wireless charging uses time-varying magnetic fields to transfer power. There are two pads, one fitted to the bottom of a vehicle (which contains an induction charging station) and the other to the ground. Power is delivered to the ground transmitter to create a magnetic field. The coil on the vehicle receives this and converts it to energy to power the battery. The principle has been around for over 100 years and can deliver rapid recharging with no wires or physical interaction necessary. 

When reading about DC charging solutions, you may also read about bi-directional charging. It can also be called vehicle-to-grid technology .Bi-directional charging enables energy to flow two ways= from the grid to the battery and the battery back to the grid.  

Bi-directional charging can play a crucial role in creating a smart grid, with battery-powered vehicles acting as energy storage devices. The process is managed by cloud software and could help us tackle one of the biggest challenges we face, how to store renewable energy. 

While wireless and bi-directional charging offers enormous future potential, conductive charging is the most cost-effective short- and medium-term solution. 

Inside DC charging grid hardware 

DC charging stations combine software and hardware to deliver a speedy recharge safely. Here are the main parts of every DC charging station: 

Grid connection – Charging stations require a solid and stable grid connection to provide the power needed for charging.

Cabinets –The hardwearing metal cabinets must be waterproof (IP54 level protection) and suitable for outdoor installation. Heliox's cabinets, for example, are built to last 15 years or more. Inside you'll find the hardware required to deliver a charge and security features, including high-speed fuses to provide over-current protection. 

Dispensers – Each charging station has a dispenser that plugs into the vehicle. There are several different DC charging interfaces, which we explore below. 

Pantograph – Some larger fleet vehicles, such as buses, use a particular type of connector known as a pantograph for opportunity charging. The vehicle parks underneath a charging station, and the scissor-like arms drop down and connect to rails on the vehicle's roof to recharge the battery. The system can deliver high-power charging at up to 600kW.charging a large vehicle such as a bus in seconds.