
How small is a hybrid’s battery? They are usually no larger than one kilowatt-hour (kWh), which is just 1 to 2 percent the size of a full electric vehicle’s battery.
Still, hybrid regen can be strong enough for most routine slowing. A computer always monitors how hard you press the brake pedal, so it will blend in the traditional brakes—the pads and rotors—during harder stops and in emergency situations. This regen-first approach maximizes the collection of electricity for propulsion so that fuel economy soars.