An electric car advertised with over 1,000 horsepower should probably come with an asterisk and an explanation.
It's true that the car can reach that power level, but only for a short time when the driver floores the accelerator. If you check the vehicle registration in some European countries, you might be surprised to see a significantly lower power figure than what the manufacturer claims.
The German magazine Auto Motor und Sport recently pointed out that, in reality, electric powertrains have two valid power levels: peak power and sustained power. Automakers typically only advertise the first level, while the second level mainly appears in type approval documents and is also the level that users frequently experience.
The second level is the continuous power output that the entire drive system can maintain without overheating. However, this figure doesn't receive much attention.
Many people are unaware that electric cars have two power levels, and the advertised level is often the maximum power that can only be achieved for a short time (Photo: Tesla).
Which parameters are important?
The maximum power output is a key factor in selling electric cars, especially high-performance models. Manufacturers aren't lying when they announce this figure, but it's not the whole story. Electric motors can receive very high currents for short periods, allowing the powertrain to generate significantly more power than it can sustain over extended periods.
The primary reason for the gap between peak power and sustained power is heat. High current generates heat inside the battery, motor windings, and inverter. When one of these components reaches a certain temperature threshold, the control system reduces the current, thereby decreasing torque and power to protect the components.
Maximum power output also depends on the battery level. Users may not notice this under normal driving conditions, but as the battery gradually depletes, the voltage also decreases, and the powertrain may no longer be able to deliver the advertised maximum power output.
There are significant differences among electric vehicle models in terms of when power drops and how noticeable the drop is. When voltage drops, the system typically has to increase current to compensate.
The difference between peak power and sustained power depends not only on the type of motor. Permanent magnet motors, induction motors, and externally excited motors have different ways of generating and dissipating heat, but the battery's power supply capacity, inverter efficiency, and the design and effectiveness of the cooling system play an even more crucial role.
Cooling capacity, battery level, and powertrain design determine the level of stability when an electric car maintains maximum power (Photo: Kia).
Electric vehicles also have a lesser-known official power rating: “maximum power for 30 minutes.” This specification is defined in UN Regulation No. 85, measuring the highest average power output that an electric powertrain can sustain during a standard 30-minute test.
That's why an electric car advertised as having 1,000 horsepower might only be recorded with a much lower figure on its vehicle registration. This is the car's continuous power output.
The 30-minute power rating is more meaningful when the vehicle is constantly accelerating, driving at high speeds for extended periods, or towing a heavy trailer.
However, this figure still cannot accurately predict the performance of an electric car in these situations, as temperature, battery level, and cooling strategy all affect the results.
However, this is a standard method for comparing power retention capabilities between different electric vehicle models.
The ability to dissipate heat determines the power of an electric vehicle.
Real-world tests have shown that the advertised numbers only reflect part of the story.
In a track test conducted by Car and Driver magazine, the 835-horsepower Rivian R1T and the 430-horsepower Lucid Air began to slow down as their battery levels decreased, while the 320-horsepower Hyundai Ioniq 5 maintained steady acceleration until its battery level dropped below 20%.
Hyundai's battery can supply more power than the motors need, creating a useful reserve. This is also something that buyers aren't fully explained by automakers: peak power indicates the best moment an electric car can achieve, while thermal management and power reserve determine how consistently the car can maintain that performance.
Automakers understand the difference between peak power and sustained power; they just don't advertise both figures. Tesla's Track Mode has a "Powertrain Endurance" setting that actively reduces power to prevent battery and motor overheating, sacrificing speed for more stable operation.
This is direct evidence from the manufacturer showing that peak power and sustained power are two different concepts, and that there is a trade-off if the user wants to maintain maximum power.
In the Model 3 owner's manual, Tesla explains that users can set Track Mode to improve the vehicle's thermal management over long distances by reducing power output as speed increases.
Reducing power output allows for better heat control, thereby slowing down the rate of temperature increase in the battery and motor. In return, the lap time will be longer, but the car can maintain more consistent performance and completion times over multiple laps.
In one test, Porsche had a pre-production Taycan perform 26 consecutive accelerations from 0 to 200 km/h, with a difference of only 0.8 seconds between the fastest and slowest. This is a very small difference. Porsche attributes this result to the car's cooling and thermal management system, which prevents the car from having to reduce power even under such extreme conditions.
Therefore, when you see an electric car advertised with extremely high power figures, it's important to note that this isn't necessarily the power level you'll experience for the majority of your driving experience.