Alternator not charging battery – what to do?

Is your car battery draining frequently? Are you looking for a way to identify the root cause of the problem? Then this article is for you! You’ll get all the information about what an alternator is, how it works and how to determine if your car’s alternator is not charging.


An alternator not charging can be an unsettling experience for drivers. Your vehicle relies on the alternator to charge the battery and provide power to your car’s electronics. If your car’s alternator is not charging, that can be due to a variety of reasons, such as a faulty alternator, a loose belt, or a dead battery. It can be difficult to diagnose the issue without the help of a professional mechanic.

However, if you notice any warning signs like dim headlights or a dead battery, don’t ignore them. Get your car inspected and replaced if necessary to avoid unexpected breakdowns on the road. Remember, regular maintenance and inspection of your car’s electrical systems can save you time and money in the long run.

Causes of an Alternator Not Charging

When your car’s alternator is not charging, it could be due to different reasons. Here are some common causes:

  1. Faulty alternator: The alternator may be completely broken or have a defective component, which prevents it from charging the battery.
  2. Broken Serpentine Belt: The serpentine belt is responsible for powering the alternator, and if it breaks, the alternator no longer turns, causing the battery to discharge.
  3. Corroded or damaged alternator wiring: Corrosion or damage to the wiring connected to the alternator may prevent proper charging.
  4. Dead battery: A dead battery may not hold a charge, even when connected to a functioning alternator.

It is a good idea to have a professional mechanic diagnose and fix any issues with the alternator or electrical system to prevent further damage to the battery and ensure the car operates reliably.

Pro tip: It’s best to regularly maintain your alternator and battery by cleaning and ensuring secure connections to avoid potential issues.

Signs of an Alternator Not Charging

A dead battery or dimming headlights may indicate that your alternator is not charging. There are several other warning signs of an alternator problem to look out for:

  • Dashboard Warning Light: Most cars have a dashboard warning light that indicates an issue with the alternator or charging system.
  • Growling or Whining Noises: A failing alternator can produce growling or whining noises due to a faulty belt or bearing.
  • A Burning Smell: A burning smell during car operation can indicate that the alternator has overheated and may require repair.
  • Faulty Electrical Systems: A failing alternator can impact the function of your car’s electrical systems, such as the radio, air conditioning, and power windows.
  • Difficulty Starting: If you experience trouble starting your car or if it stalls frequently, the alternator may not be charging the battery properly.

It is essential to have your alternator checked by a professional mechanic if you notice any of these signs to avoid further damage to your vehicle.

Diagnosing an Alternator Not Charging

When your car battery is continually dying or the battery light is illuminated on your dashboard, it could indicate that your alternator is not charging properly. Diagnosing an alternator not charging is a relatively simple process.

Here are a few things to check:

  • Start your engine and measure the voltage across the battery terminals using a voltmeter. A fully charged battery should measure between 12.5-13.8 volts. If the voltage is below this range, it could indicate that your alternator is not charging the battery.
  • Check the alternator belt. If it is loose or worn out, it will not be able to turn the alternator pulley effectively, leading to a lack of charging.
  • Inspect the alternator connections. Loose, corroded, or damaged connections can prevent the alternator from charging the battery.
  • If you have checked all of these and still have issues, it may be worth having your alternator tested at a trusted mechanic.

Pro Tip: If you own an older vehicle, it’s a good idea to have your alternator tested annually to catch any issues early.

Alternator Not Charging Solutions

When the alternator is not charging, it can cause various problems with your car’s electrical system, such as difficulty in starting the engine, dimming lights, and a dead battery. Here are some solutions to consider if your car’s alternator is not charging:

  1. Check the alternator belt: A worn-out, loose, or broken alternator belt can reduce the electrical output of the alternator, causing it to undercharge or fail to charge the battery.
  2. Inspect the wiring connections: Loose, corroded, or damaged wiring connections can disrupt the current flow from the alternator to the battery, leading to charging problems.
  3. Test the battery: A weak or dead battery can prevent the alternator from charging correctly. Ensure that the battery is fully charged and in good condition.
  4. Replace the alternator: If the alternator is faulty or damaged, replacing it with a new one can solve the charging problem.

If your car’s alternator is not charging, it’s crucial to diagnose and fix the issue promptly to avoid further damage to your car’s electrical system.

How to Avoid Alternator Not Charging Issues

The alternator is one of the most crucial parts of a vehicle’s charging system, responsible for converting mechanical energy into electrical energy to charge the battery while the engine is running. A common issue faced by many car owners is the “alternator not charging” problem, which can lead to battery failure and electrical system breakdown. However, there are a few steps car owners can take to avoid alternator not charging issues.

Here are some tips to help you avoid the alternator not charging problem:

  • Regularly inspect the alternator belt for wear and tear and replace it if damaged.
  • Keep the battery terminals clean and free of corrosion to ensure proper electrical flow.
  • Avoid overloading the vehicle’s electrical system with too many appliances that may drain the battery and overload the alternator.
  • Schedule regular maintenance checks with a professional mechanic to catch any signs of alternator failure early on.

By following these simple tips, car owners can prevent alternator not charging problems and ensure reliable vehicle performance.

Frequently Asked Questions

Q: What are the common signs of a faulty alternator?

A: The common signs of a faulty alternator include:

  • Dim lights
  • Warning lights on the dashboard
  • Strange noises from under the hood
  • A dead battery
  • A burning rubber smell

Q: What causes an alternator to stop charging?

A: The common causes of a malfunctioning alternator include:

  • A broken belt
  • A blown fuse
  • A faulty voltage regulator
  • A bad diode

Q: How long can a car run with a bad alternator?

A: A car can run for a short time with a bad alternator, typically between 20 and 30 minutes. However, it’s not recommended to drive the car with a dead alternator as it will eventually stall and leave you stranded.

Q: Can a car still run if the alternator is not working?

A: In most cases, a car cannot run if the alternator is not working since it’s the alternator that provides the electrical power to the battery and other electrical components in the vehicle.

Q: How much does it cost to replace an alternator?

A: The cost of replacing an alternator varies depending on the make and model of your vehicle and the location of the repair shop. However, the average cost ranges from $300 to $500. Pro tip: If you suspect a faulty alternator, it’s best to get it checked and replaced by a professional as soon as possible to avoid any further damage to your vehicle.


In conclusion, if your alternator is not charging, the issue could stem from a range of causes, including a worn-out alternator, loose or damaged belts, corroded or loose connections, or a weak battery. To diagnose and fix the problem, it is essential to:

  1. Use a voltmeter to check for proper battery voltage
  2. Test the alternator output
  3. Inspect the belts and connections

However, it’s essential to note that ignoring a malfunctioning alternator can lead to a completely drained battery. In severe cases, it can also cause engine stalling while driving. If you encounter any issues with your alternator, it is always best to seek professional assistance for prompt and safe repairs.

Pro tip: To prevent alternator failure, ensure that your vehicle routinely undergoes preventative maintenance, including regular inspections and the replacement of worn-out belts and batteries.


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