Why are car batteries measured in WattHour (kWh) but phone batteries are measured in AmpHour (mah)?

Question

Edit: I am talking about EVs

In: Physics

Answer 1

Car batteries are usually rated in amp-hours and cold cranking amps. But the only difference between Watt-hours and Amp-Hours is the battery voltage. If you are given a battery rated in Amp-hours, just multiply by the nominal voltage and now it’s in Watt-hours.