Your battery and alternator work together to supply the electricity your car needs to run. If your engine turns slowly when trying to start it, or the lights get dim when you turn the car off, either of those parts could be at fault. Here is how to tell if the battery is the problem so you can get to the auto parts store for a replacement before you run completely out of power.
How the Battery and the Alternator Power Your Car
The battery is a static source of electricity that powers the car when the engine is turned off. The alternator produces electricity only when the engine is running. Here is how they work together:
- When you start your engine, the battery is used to operate the starter, which turns the engine over.
- When the engine starts, the alternator begins producing electricity and takes over from the battery.
- While the engine is running, the alternator charges the battery.
- As long as the engine is running, the alternator provides electricity to the car and its accessories. If you turn on several accessories, the battery may help a little.
- As soon as you turn the engine off, the battery takes over so you can play the radio and turn on the various lights in the car.
What Happens When Things Go Wrong
Car batteries can only be recharged so many times. Manufacturers state how long they estimate their batteries will last under normal conditions. Eventually, the battery will stop taking a charge and when they are drained of power, they are dead. The symptoms of a dying battery include:
- The engine turns over slowly, or not at all, when trying to start the car.
- The lights dim when you turn off the engine.
Faulty alternators can stop producing electricity when the engine is running. This means the battery becomes the only source of power. Should this happen, you're likely to experience such symptoms as:
- The car begins to miss and run rough.
- The lights dim and the radio fades in and out.
- When the battery has been drained of power, the car stops dead.
Testing the Battery and Alternator
If you can drive your car to an auto parts shop, they will test your battery and alternator. Or you can do a simple test in your driveway.
- Start the car.
- Find the battery under the hood in the engine compartment.
- Remove the black (negative) battery cable from the battery terminal.
- If the engine continues to run smoothly for several minutes, the alternator is likely fine. This points to a battery problem.
- If the engine starts running rough, then the alternator is faulty.
You'll need to take your car to an automotive repair shop to get the alternator fixed. They will also charge your battery up for you. You can get a replacement battery from the auto parts shop and change it yourself.
At the first sign of any electrical problems with your car, identify the issue and get it fixed quickly. When batteries and alternators fail, they do so quickly. You may find yourself stranded along side of the road waiting for a tow truck with a dead car.
For more information or assistance, contact an auto repair company such as Gordie's.