Actually, your car wouldn't need a battery at all if it didn't need to be started! Almost all the drain on your car battery is from the starter motor, which is incredibly strong (as you will see if you operate it by mistake while the car is in gear - it's strong enough to make the whole car jump forward!) Once the car is started, part of the power from the engine is diverted to re-charging the battery and to operating any electrical equipment like the lights and radio, but it can take quite a while before the battery regains its charge! More sophisticated cars actually turn off the headlights and other electrical devices completely for the moment when you operate the starter motor, so all the energy from the battery can be diverted to the starter motor. In older or cheaper cars, if you're having trouble starting the car, turn off the lights and radio (and aircon, for a different reason) and try again. If you can avoid using electrical devices, your battery will charge more quickly.
60 mths ago