If your car shows signs of trouble starting or stalling while driving, you may wonder: is it just a bad alternator or battery? These vital parts help your car start, but its functionality is entirely different.

It is essential to know the symptoms to differentiate between a bad car battery and a bad alternator so you do not spend much time making your car roadworthy again. In this article, you will learn how to understand these two regular automotive issues and what to do if one fails.

Understanding the Basics: What Do the Battery and Alternator Do?

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So, let’s first identify what part each component needs to play before seeing the signs of a bad car battery vs alternator.

The Battery: Your car’s battery charges a few electrical systems on it and supplies power to start the car’s engine when required. It supplies the necessary current of electricity to the firing system to spark the engine’s ignition system, start the lights, and provide other electrical equipment when the engine is not in functioning mode.
The Alternator: While the engine is running, the alternator charges the battery. In cars, it charges the battery from energy produced by the engine and supplies the car with the electrical power needed to operate its various parts. An alternator, when not working, would mean your battery would soon die, and your car wouldn’t start, let alone run.

By understanding how both these components work, you will be able to identify which of the two is defective whenever your car is faulty.

Signs of a Bad Car Battery vs Alternator: How to Spot the Difference

Now that we understand the function of each component, let us examine the symptoms of a bad car battery compared to that of a bad alternator. Even though they may lead to similar effects, there are major distinctions in the way you feel and how your auto responds.

  1. Dim or Flickering Lights
    The next sign is either haze or blinking under the section of headlights. Since both the alternator and the battery are chargers for the electric systems of the automobile, this can be caused by either of them.
    Bad Battery: But as much as it hails the use of headlights, it is evident that they are usually dim, particularly when you start the car due to a failing battery. This is because stored power within the battery is low to provide adequate energy required to power the used electrical systems.
    Bad Alternator: A bad alternator, however, will cause the headlights to become either dim or to flicker while the car is moving. This is because the alternator is not charging the battery all the time; the power supply tends to fluctuate.

  2. Warning Lights on the Dashboard
    Today, cars have warning lights that make it possible for you to tell us about some of the issues that your car could be having. However, since the alternator and incorrect battery are two separate components of a car’s charging system, they display identical warning lights but do so in distinct ways.
    Bad Battery: Common signs that indicate that your car battery is bad are that the “Check Battery” or “Battery Warning” light may come on. This light normally comes on when the battery is not charging, or the battery is almost drained.
    Bad Alternator: Charging system refers to the signal name of the battery on the Full Digital Cluster Display that illuminates if the alternator is the issue, so you will see the ‘Charging System’ warning light, which is also known as the ‘Alt’ light. Here, it shows that the alternator is not charging the battery as it should normally do.

  3. Strange Sounds
    Another useful indicator of a bad battery vs alternator is unusual sounds coming from the car.
    Bad Battery: When the battery is faulty, you hear a clicking sound when you try to start the engine. This is when the vehicle has a weak supply of electricity to turn the starter motor, so it only tries to turn the engine over.
    Bad Alternator: If your alternator is failing, you might hear a whining or grinding noise, which means your internal bearings or alternators are not functioning properly.

  4. Electrical Issues and Malfunctions
    A bad alternator and a bad battery will both cause electrical problems, but the kinds of problems are different.
    Bad Battery: A bad battery can cause dim lights, slow cranking, no radio, no accessories, no start, or even slow starting. These may function properly occasionally or may not work at all if the battery power is insufficient.
    Bad Alternator: If the alternator is bad, the electrical components of the car will run while the engine is on, but when the battery is dead, they will not. Unlike a car that can continue running on reserve power, if the battery in our homes is drained, everything from the lights to air conditioning will come to a standstill.

How to Diagnose the Problem

All those in doubt about whether they have a bad alternator or a bad car battery should be sure to make a correct diagnosis. Here’s how you can check for the problem:

Test the Battery: Another way of confirming that the battery is the problem is by attempting to jump-start the car. If the car starts and the engine starts and operates correctly later, then the battery may be at fault. An experienced mechanic can use a multimeter to try to charge and also check the health of the battery.
Test the Alternator: If the battery is okay, but the car still develops more electrical problems, then the alternator may be a culprit. A mechanic will give a go signal if the voltmeter reads below the 100s or will bring the car to an auto parts store to have it tested.

What to Do if You Have a Bad Battery or Alternator

If you’ve determined that either your battery or alternator is bad, you’ll need to take steps to fix the issue:

Bad Battery: Just like any other lithium-ion battery, if the battery is dead or it’s not charging, then it has to be replaced. Car batteries can also have a lifespan that is as good as that of a car, with regards to 3-5 years starting from the moment it was bought, and this depends on factors such as use and weather.

Bad Alternator: If there is a problem with the car, then at least the alternator, for instance, would have to be changed as well. Occasionally, a fix can be as straightforward as changing the belt, or it will take just a minor fix to adequately address, and in others, the alternator is better left to a mechanic.

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It is very important for every driver to recognize the differences between the symptoms of a bad car battery and those of a bad car alternator. There is also the benefit of being able to detect the signs early so you don’t get left with a dead car and, worse still, having your car damaged. Whether it is a battery or alternator problem, it’s important that one finds out what the problem is and has it fixed so that his car works as it should. If you notice signs of anything wrong, take your car to the best mechanic you can find to get it fixed before it worsens and requires expensive repairs.

Ready to take action? Read the warning lights in your car today and get your automobile back to its best!