> The vast majority of cars already have a small electrical generator installed. Plugging things into a cigarette socket to access that electricity causes 0 extra load on the engine.
No. Your use of energy from the generator through the cigarette socket manifests as a braking force in the generator. The more energy you use, the more it brakes. The car's engine has to work harder to overcome that braking.
No. Your use of energy from the generator through the cigarette socket manifests as a braking force in the generator. The more energy you use, the more it brakes. The car's engine has to work harder to overcome that braking.