Electric cars have turned horsepower figures into something that looks like a mid-century telephone number.
But those four-figure outputs plastered across brochures don't necessarily represent what your EV can produce continuously.
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As Germany's Auto Motor und Sport explains, peak and sustained power are very different animals.
Take the Porsche Taycan Turbo GT: Porsche lists its regular output at 778 hp (789 PS / 580 kW).
Activate Launch Control and that jumps to 1,019 hp (1,034 PS / 760 kW), while maximum Overboost briefly unlocks 1,093 hp (1,108 PS / 815 kW) for just two seconds.
The Numbers Behind the Numbers
Porsche says its quoted Taycan outputs are determined using UN Global Technical Regulation No. 21, or GTR 21.
This establishes a standardized method for determining the combined system power of electrified vehicles.
That's particularly useful with multi-motor EVs because you can't necessarily just add each motor's maximum output together and call it the car's total.
And that's where EV power figures get confusing.
GTR 21 system power isn't the same thing as continuous power.
Electric motors can swallow huge currents and generate tremendous output briefly, but heat eventually becomes the party pooper.
Battery temperature and charge level matter too, as do the inverter, motor and cooling system.
The 30-Minute Power Figure
That's why yet another number exists.
UN Regulation 85 (ECE R85) includes a measurement for an electric drivetrain's maximum 30-minute power, essentially establishing how much output it can sustain on average across half an hour.
