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400 volts vs. 800 volts: the advantages of high battery voltage in electric vehicles

Advantages of 800-volt technology

Lower weight, higher continuous power and shorter charging times: these are the advantages of the 800-volt system voltage at Porsche.

Even more concretely: If you carry less ballast, you accelerate faster, brake shorter, take more speed through the curve, protect the tires and save drive energy. On the racetrack, more continuous power translates into more laps in a row without sacrificing performance. But the fact that 800-volt technology also shortens charging times and saves energy due to fewer losses requires a more detailed explanation.

Die 800-Volt-Technik des Porsche Taycan, 2024, Porsche Schweiz AG
The 800-volt technology of the Porsche Taycan

This reduces loading times

Let's start with the loading times. There are two main options for getting the electricity from the charger into the battery more quickly: thicker high-voltage cables or a higher voltage. For the sake of simplicity, let's imagine a garden hose: instead of electricity, water flows. Bottlenecks slow down the flow of water.

If we now take a thicker hose, we can let more water flow – a simple solution. A thicker hose, however, is heavier and takes up more space. Suboptimal for a sports car in the figurative sense.

The second option is to turn on the tap further to increase the water pressure. This is because with higher pressure, the water flows faster through the hose. In electric cars, this means increasing the system voltage.

Volts (V): Unit of measurement for electrical voltage

Whether thicker hose or higher water pressure: With both options, more water sprays out of our hose faster. Porsche chooses the latter approach, because the absence of thicker high-voltage cables saves weight and installation space.

Taycan-Prototyp, Hochgeschwindigkeitsstrecke in Nardò, Italien, 2019, Porsche Schweiz AG

How much current "fits through" a line at all is indicated by the unit for the current (ampere). Our hose can also only hold a limited amount of water. Logically, more if it is thicker, but even then it would burst if there was too much water. Current fast-charging stations usually limit the current to 500 amps – safety buffers included.

Ampere (A): the unit of measurement for the current

A 400-volt vehicle can theoretically provide 200 kilowatts of charging power at 500 amps. If you turn on our metaphorical tap further and double the water pressure to 800 volts, then even 400 kilowatts of charging power are possible, i.e. twice as fast charging. At least on paper, because in practice other factors limit the charging power, for example the cooling of the components in question both at the charging station and on the vehicle.

Charging power in kilowatts (kW): the product of voltage and current

With its maximum charging capacity of 320 kW, the revised Porsche Taycan, which will be available from 2024, is correspondingly short on the so-called High Power Charger (HPC): This means that up to 315 kilos of payload are possible in just ten minutes. And the charge from 10 to 80 percent ideally takes place in just under 18 minutes.

Lower consumption despite more power

The high voltage level not only provides more power when charging, but also provides more power when riding. Thanks to lower currents in the vehicle, less waste heat is generated, which impairs the performance of the electric motor and other high-voltage components. In other words, in our thinner hose with less water, fewer water droplets rub against each other – after all, heat is generated by friction.

Jonny Smith, Host des YouTube-Kanals „Fully Charged“, 2024, Porsche Schweiz AG
Jonny Smith, host of the YouTube channel "Fully Charged", completed the sprints at the Lahr airfield in Germany.
Taycan-Prototyp, 2024, Porsche Schweiz AG
The very first Taycan already proved this with a pre-production vehicle: 26 times in direct succession, it accelerated from zero 0 to 200 km/h in an average of 10 seconds. The difference between the fastest and the slower attempt: only 0.8 seconds.
Jonny Smith, Host des YouTube-Kanals „Fully Charged“, 2024, Porsche Schweiz AG
Jonny Smith, host of the YouTube channel "Fully Charged", completed the sprints at the Lahr airfield in Germany.
Taycan-Prototyp, 2024, Porsche Schweiz AG
The very first Taycan already proved this with a pre-production vehicle: 26 times in direct succession, it accelerated from zero 0 to 200 km/h in an average of 10 seconds. The difference between the fastest and the slower attempt: only 0.8 seconds.
 

This means that an 800-volt Porsche has to invest less power in cooling itself, can repeatedly perform launch control starts without slowing down. It also circles the more than 20-kilometre-long Nordschleife of the Nürburgring without any significant loss of performance.

On top of that, the lower so-called heat losses make it more efficient. This is because electrons that "fizzle out" as heat due to friction are no longer available to the electric motor for conversion into drive energy. Electrical energy thus becomes thermal energy instead of kinetic energy. Losses that must be minimized both when calling up the power and when feeding, i.e. when driving as well as when charging.

The Porsche Taycan was the first electric vehicle to bring a system voltage of 800 volts into series production. With the three-time Le Mans overall winner and sports car world champion 919 Hybrid, Porsche had already successfully used the technology in motor racing.

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