Why Does My Car Battery Keeps Dying

Why Does My Car Battery Keeps Dying?

Do you have a car battery that keeps dying no matter how much you charge it? You need to figure out what’s draining your battery and whether it’s being charged properly. Regularly charging the battery won’t solve the problem.

A car battery that keeps dying is a sign of a problem with the battery itself or a faulty alternator. There are three possibilities, either something is draining the battery, the battery is dead, or the battery is not being charged properly.

You should never trust a battery that keeps dying, it will die eventually. Fortunately, diagnosing a problem with car batteries is relatively easy. Follow this guide to find out why your battery keeps dying and how to fix it.

Why Did My Car Battery Die

Why Did My Car Battery Die

  • The battery is bad or dead. 
    Car batteries have a lifespan of 3-4 years. After that, the capacity of the battery is decreased, and it starts to self-discharge. This can only happen if the battery is often drained flat. A completely dead battery can be recharged but it will lose its capacity. So, the battery will keep dying, regardless of whether you charge it or not.
  • The alternator is not charging the battery.
    The car battery may be completely fine but the alternator is not charging it. The alternator is the part that’s charging the battery while the engine is on. The battery will eventually die because it’s not being charged. [Source]
  • There is a drain. 
    Lastly, there may be a drain that you don’t know about. Electrical components that keep working after your car is turned off can be a possible cause. Headlights left on is also a common cause.

These are the three things you need to check out to locate the problem, the electrical components, the battery, and the alternator. Here’s how you can check that out.

[Related Article: The Complete Beginners Guide For Car Battery]

How Do You Know If Your Battery Is Bad

The most reliable way to find out whether your battery is okay is to perform a test with a multimeter. There are some things you can check out before that but these things are rarely conclusive.

Dimmed headlights, car struggling to start because of low cranking, battery sign on the dashboard, and weakened electrical system are signs that your car has a bad battery. 

However, the battery may be performing badly because it’s not being charged properly. You need to be sure that the problem is with your battery and not the alternator. Otherwise, replacing the battery won’t do anything. The new battery will die as well.

How To Test A Car Battery

To test a car battery, you will need a multimeter. Make sure to get one or visit someone that has one. Here’s how to do it.

  1. Turn off the engine.
    A car battery should be tested with a turned-off engine when it’s not being charged.
  2. Set the multimeter to 12 V.
  3. Connect the red clamp to the positive terminal. 
  4. Connect the black clamp to the negative terminal.
  5. Read the measurements on the multimeter. 

A car battery should have a voltage of 12.6 V or higher. Measurements below 12.6 V while the engine is off means that your battery is dying.

[Related Article: How To Change A Car Battery]

How Do You Know If Your Alternator Is Bad

How Do You Know If Your Alternator Is Bad

As mentioned, the alternator is responsible for switching to an AC current so the battery can be charged while the car is running. The tricky thing is, with a brand-new battery, it will take some time until you notice that your alternator is bad. The only way to test an alternator is with a multimeter.

How To Test An Alternator

  1. Turn on the engine.
    The alternator should be tested with a turned-on engine. Make sure there are no electrical components running that may be draining the battery.
  2. Set the multimeter to 12 V.
  3. Connect the clamps to the battery terminals.
  4. Read the measurements on the multimeter.

A healthy alternator will provide a voltage of 13.7 V or higher to the car battery. If your car battery has a lower voltage of 13.7 V while the engine is running, the alternator is not charging the battery. So, you will need to replace or fix the alternator.

How To Find Out What’s Draining My Car Battery

If your battery is new, and there’s no chance it’s dead. And, the alternator is charging the battery properly, then, something must be draining the battery. Most of the time, it’s obvious when something is draining your battery.

But there are some situations where a device can drain your battery without you even noticing it.

  • The most common causes of a battery drain are the headlights, the radio, and added electronics devices(GPS). 

Try to remember if you left the headlights on or if you drained your car battery flat. If so, your battery may be dead. Some batteries die after going flat. The capacity is decreased and the battery starts to self-discharge. So, even if you eliminate the drain, your battery will keep dying.

If the headlights are not the problem, most of the time some electrical device that you added is the culprit. This is a very common case with people that add GPS, a loud horn, strong sound systems, etc…

The easiest way to find out what’s draining the battery is to plug off these devices one by one and see where the drain is coming from. For instance, if you remove the GPS, and your battery is not drained anymore, the GPS was the source of the drain.

Tip: Get a smart battery tender for your car. This device will keep the battery topped off when you are not using it.

You can also try using a multimeter. Turn on the engine, and remove the devices one by one. See with what device the voltage goes down below the recommended number.

Related Question And Other FAQs

How Do You Stop A Car Battery From Draining When Not In Use

If a car battery is being drained by something when not in use, the drain needs to be eliminated, provided that the battery is healthy. You can also try using a battery tender to always keep your car battery fully charged.

Can Alternator Drain Battery

The alternator can’t exactly drain car batteries. Instead, the alternator may not be charging the battery. It’s responsible for switching the current to AC so the battery can charge while you drive. If the alternator isn’t working, the battery will not charge.

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