The car battery is what powers all the electrical components of the car. It is typically a rechargeable 12 volt lead-acid battery that powers the electrical system in the vehicle. This means that there are various chemicals in the battery that goes into a reaction when it is in use. When it is recharging, the chemical reactions are reversed.
Car Battery Components
The main components of the car battery is that it starts the starter motor and the ignition system. The starter motor is basically an electric motor that gets the main gas engine going. The ignition system is what ignites the mix of gas and air to produce the combustion the engine needs to keep it running.
Everyone knows that when the car battery dies, you can’t start it anymore. There can be many reasons a car won’t start, but when you hear that clicking noise, and no ignition, than it is probably a dead battery. The clicking noise is telling you that you starter is working, but it’s not engaging the battery. When the starter is dead, you won’t here a clicking noise.
The car battery also runs the electrical system of the car. The main component to the electrical system are the lights. The headlights, interior lights, trunk light, and the dashboard light are all powered by this 12 volt battery. That is why when you leave the lights on, the battery drains and you can’t get the car started.
So the next question is, how come the car battery drains so quickly that you can’t start the car, when you leave the lights on, but it can power the lights for a seemingly unlimited amount of time while you’re running the engine? The first part of the answer is that it takes close to a full 12 volts to start your car. So if you’re battery is at 11.2 volts, sorry but you’re probably out of luck. The second part of that has to do with how it recharges itself as it runs.
How It Recharges
You car has something called the alternator. This takes the mechanical motion of the engine, via alternator belt, and produces electricity to recharge the battery. It’s like a give and take relationship. The car battery starts the engine, which in turn recharges it back up as it runs on gasoline. That’s why after you jump start a car, you should probably run it for a while before you shut it off again.
There is a little computer attached to the alternator that tells it to charge or stop charging the battery. That’s a great little thing to have working because if you overcharge the battery, you can create hydrogen and that can cause the battery to explode.
So why then do you have to buy a new car battery every so often? Well, because the batteries tend to not hold the charge as much as time goes by. Most 12 volt batteries actually hold close to 13 volts. A mechanic once told me that they call it 12 volt batteries because 13 is an unlucky number. I don’t know if that’s an urban legend or not. But either way, it holds more than 12 volts. Then over time it starts to fade. And when it can’t hold much more than 12 volts anymore, than it’s time to get a new battery.