Why 800V cars are changing the game

It’s a figure that’s becoming increasingly common on electric car specifications: 800V. This is not a trivial value. While the vast majority of electric vehicles operate with a 400V electrical architecture, the latest models such as the Volvo ES90, Porsche Taycan, Audi e-tron GT, Hyundai Ioniq 5 and 6, Kia EV6 and Genesis GV6 are doubling the voltage. The aim is to charge much faster, especially at ultra-fast charging stations. But how exactly does this work?

Volts, kilowatts, kilowatt hours: what does what?

To understand the benefits of these architectures, we first need to clarify three essential concepts in electric mobility.

• A volt (V) is the force that pushes electrons through an electrical circuit, comparable to the pressure in a water pipe. The higher the voltage, the faster the electricity flows.

• A kilowatt (kW) is power, i.e. the amount of electricity flowing at a given moment. This determines the charging speed.

• Finally, the kilowatt hour (kWh) represents the amount of energy that can be supplied over a given period (1 hour); in other words, how much ‘electric fuel’ the vehicle’s ‘electric tank’ has.

A typical electric car has a battery between 60 and 100 kWh. To ‘fill it up’, the charging station will deliver a certain amount of power in kW for a certain amount of time. An 11 kW charging station will take around 7 hours to fully recharge a 77 kWh battery. A 350 kW charging station? Less than 20 minutes to go from 10% to 80% (depending on the car’s on-board charger).

Why does 800^V change everything?

The advantage of an 800^V architecture lies in its ability to deliver more power with less heat. According to the law of electricity (P = U × I), to deliver high power (P) in watts, you need either a high voltage (U) in volts or a high current (I) in amps. By doubling the voltage, you reduce the current required, which limits energy losses due to overheating of cables and electrical components.

As a result, 800^V cars can take full advantage of the new generation of fast charging stations (150 to 350 kW), while 400^V models are often limited to around 125 to 150 kW.

Where can you charge your car with 800^V?

But you still need to find the right charging stations. In Luxembourg, the public network has around 88 ultra-fast ‘SuperChargy’ stations, deployed on major roads and in park-and-ride car parks. These offer up to 350 kW, making them fully compatible with 800^V vehicles. In Europe, networks such as Ionity, Fastned and the new Tesla V4 Superchargers are rolling out these stations on a large scale.

But beware: an 11 kW charging station, which is very common in cities or at home, does not allow you to take advantage of the 800^V architecture. It charges at the same speed as a 400^V vehicle, via the vehicle’s on-board charger. The advantage of 800^V only becomes apparent with very high-power direct current charging stations.

Ideal for frequent drivers

If you mainly charge at home, an 800^V car will not bring any significant benefits. But if you are a frequent driver who likes motorways and long journeys, the 800^V architecture represents a real step forward. Provided, of course, that the charging stations keep up.