Why electric cars lose horsepower on highways?

The sources explain that electric cars seem to "lose horsepower" on highways due to the fundamental difference between Peak Power and Nominal Power.Here is a description of the key concepts covered in the sources regarding this phenomenon:The Technical "Paradox"

• • Peak Power: This is the high horsepower figure typically seen in marketing brochures. It represents the maximum effort a motor can exert for a very limited time, such as during a quick start or overtaking.
  • Nominal Power: This is the "real" power the car can maintain for a long duration (often defined as 30 minutes) without the motor, inverter, or battery overheating.

• • Citroën ë-C3: Drops from a peak of 113 CV to a nominal 45 CV (comparable to an old Fiat Panda).
  • Peugeot e-208: Drops from 156 CV to 78 CV.
  • Tesla Model 3 RWD: Drops from 283 CV to 120 CV.
  • VW ID.3: Drops from 204 CV to 95 CV.

• • Advanced Thermal Management: Systems that use active liquid cooling keep the battery and motor at ideal temperatures.
  • 800-Volt Architecture: Found in cars like the Hyundai Ioniq 5 and Kia EV6, this system generates less heat during high-speed travel, allowing for more stable performance.
  • Native Electric Platforms: Cars designed from the ground up as EVs (rather than adapted from combustion frames) generally handle thermal stress better.

Why Performance Drops on HighwaysIn urban driving, a car uses its peak power for short bursts, and the system has time to cool down between stops. However, during sustained high-speed highway driving, the electronics must stabilize the output at the nominal power level to prevent thermal damage. In practice, this means an electric car "transforms" into a much less powerful vehicle during long trips.Real-World Power ComparisonsThe sources provide a comparison of how different models perform once they settle into their nominal power:Factors that Mitigate Power LossNot all electric cars lose power to the same degree. The sources highlight several technologies that help maintain performance:This thermal constraint is a standard characteristic of DC motors; for instance, eBike motors also list peak vs. nominal wattage because running at peak levels for too long would cause the internal coils to overheat.