A car (any) battery is essentially a device that produces lots of electrons at one point (one of it's termials/electrodes whatever) and not so many at another point. This gives you a potential (voltage) difference between the two points.
Electrons don't like each other so they want to go where there is less of them so when you create a path to such a place (electronic circuits in your car) they will travel to the place they are happier and voila you have electrical current flowing.
Edit: the battery's job is to maintain the potential difference through other energy means, like chemical reactions.
Originally posted by CabaHence, then electrical energy you get is equal to sum of all other kinds of energies required to maintain this potential difference. In most occasions that's chemical energy.
A car (any) battery is essentially a device that produces lots of electrons at one point (one of it's termials/electrodes whatever) and not so many at another point. This gives you a potential (voltage) difference between the two points.
Electrons don't like each other so they want to go where there is less of them so when you create a path to such a place (el ...[text shortened]... is to maintain the potential difference through other energy means, like chemical reactions.
In an automotive system the battery is basically like a reservoir. It's main purpose is to start the car/truck. To crank the motor over. Once the car/truck is running then the alternator takes over and supplies the power for all of the electrical devices on the car/truck. The alternator also keeps the battery topped off. I work for an auto parts chain so I have to sell Batteries/alternators to customers all of the time.
Manny