Battery Charging System: What You Should Know

Published: January 7, 2023
Last updated: November 13, 2023

Since the battery controls functions such as your car's ignition and lighting, the battery charging system is vital to its operation. As a result, the charging system for the service battery is connected to other systems, including the ignition system, the navigation system, the lighting system, the fuel system, and the engine management system, among others. That is why battery charging systems require special attention when they need to be serviced.

A number of other systems rely on it, so it's more or less a central system. For you to get the best driving experience from your vehicle, you must know how it works.

What Is Battery Charging System?

Cars have different battery charging systems depending on their age. Electronic control units or computers are usually part of the charging system in cars, as are batteries, alternators, and wiring.

A voltage regulator was needed to optimize the alternator's performance in cars made before the 1990s. The alternator generates electricity once the engine starts, and the voltage passes through the car's electrical system. There is a battery light that comes on whenever the voltage is imbalanced in this system.

With the development of more advanced cars, car manufacturers replaced voltage regulators with computers that provide accurate voltage readings. Modern battery charging systems illuminate the battery light when they detect voltage changes in the system. This is where a reliable auto shop like JBA Speed Shop comes into play. They specialize in ensuring that your battery charging system, among other essential components, is always performing optimally.

Using these components as a system, let's look at how they interact:

The Alternator

Electricity is generated in the alternator by converting mechanical energy from the engine into electricity to power the car's accessories and boost the battery power.

The Electronic Control Unit

By regulating how the car's electrical power is allocated, the electronic control unit controls the electronic system. In essence, it controls how much electrical energy the alternator produces. The sensor also detects when the car battery needs charging and when the car's energy flux changes.

The Battery

Batteries are essentially banks for the electrical energy that is generated by alternators. Car engines are started with energy that comes from the battery's store. Additionally, it supplies power to the accessories of the car when the engine is not running or when the alternator fails.

The Wiring

Battery charging systems consist of a network of wires connected to three components. Understanding how these components work together is crucial for maintaining a reliable electrical system in your vehicle. If you're interested in upgrading your charging system, click for one wire alternators to explore efficient and streamlined options that can enhance your vehicle's electrical performance.

What’s Happening When the Battery/Check Charging System Light Comes On?

On the dashboard of your car, the battery/check charging system light is an important warning light to pay attention to. A battery-shaped amber or red symbol could be called "Bat" or "Alt," according to the car.

If the battery charging system is serviced, what does it mean? There is only one reason why this light appears on the dashboard: something is wrong with the car's charging system. A faulty battery charging system causes it to only come on while driving, and the battery is being used to power the car's operations.

The car's electrical energy generation system has some problems, so it doesn't generate enough power to run optimally. Battery charging is not happening at this point. The battery will eventually run out of electricity and die. A dead battery will cause the car to stop working. Thus, you only have a short window of time to resolve whatever triggered the light. This situation could be explained in more detail in your owner's manual.

What Can Cause My Battery/Check Charging System Light To Come On?

It is possible for your car's battery/charge system light to come on for several reasons. You can find a few examples here.

Problems with the Drive belt

Powered by the alternator's pulley, the drive belt turns the alternator's pulley and turns the alternator. The alternator's performance will be affected by a worn or non-functioning drive belt. For example, it might not turn fast enough or keep slipping off. Alternators in both cases are not performing as well as they should, which causes the check charging system light to illuminate.

Wiring Issues

The check charging system's wiring network also plays an important role in the alternator's operation. The battery system light will illuminate if there is a problem with the wiring, which ultimately affects the battery voltage generated.

A Bad Electrical Control Unit

Electrical control units, or computers, play a crucial role in how battery charging systems operate because they regulate the alternator's voltage. The voltage regulation and checking of the charging light will be affected if there is a problem with the electrical control unit.

Battery Issues

One of the main reasons why the battery charging light appears on a car is a failed car battery. As a consequence, the battery is unable to store any electrical charge, which ultimately affects its ability to charge.

The battery charging system can also be affected by issues with the car's battery terminals. Battery performance will be adversely affected by corrosion or disconnected terminals, triggering the check charging system light.

A Failed Alternator

A battery charging system would not be complete without the alternator, which converts mechanical energy into electrical energy. The check charging system light will illuminate if your alternator fails since the voltage won't be regulated as it should be.

Is It Safe To Drive With The Battery/Check Charging System Light On?

Driving around with the "battery" and the "check charging system" lights on is not ideal. Your only option whenever this light appears is to drive to a mechanic shop to fix the problem.

Whenever the battery charging system does not function properly, this light comes on. Whenever this light appears, you're in a race against the clock to fix the issue.

In the event that you don't resolve the problem ASAP, the car might shut down without any warning, which could pose a serious safety hazard to you and other road users. The problem might be improved by turning off the air conditioning, stereo, and pretty much everything that consumes electricity. It is best to take some professional help once the service battery charging system light comes on to reset it. In the absence of this, you might run into some serious problems.

How Do I Check My Charging System?

Checking the charging system yourself is one way to resolve the battery/check the charging system light. This could be a good step for you to take. Regardless of what type of vehicle you own, here's how to check your car's charging system. If you want to service the battery charging system on a Chevy Cruze, for example, here's how.

Check the Battery

Checking the condition and charge of the car battery is the goal. If a green eye appears in the battery's hydrometer, check it.

The terminal connections of the battery should also be clean and well-fastened, so no corrosion residue is left behind. Make sure the battery terminal is clean if there are residues or corrosion.

You should also check the voltage at the battery terminals. With no loads attached, it should have a voltage of about 12 volts.

The battery can also be tested with a test light or multimeter to ensure that it is functioning properly. The following steps will help you.

  • You need to flip your Battery tester to the 'OFF' position.
  • The multimeter selector switch is then flipped to DV volts.
  • In the next step, you will attach both tools to the positive post of the battery. Make sure the negative test lead is connected to the negative battery post. It is also important to ensure that the multimeter clips do not touch the tester clips on the battery posts.
  • The ammeter should display about half of the battery's cold-cranking amps when the load control knob is set to the right-handed position.
  • The multimeter reading is then observed. At 21 degrees centigrade, a battery capacity of 9.6 volts indicates good performance. Battery failure is indicated by any reading below that. If you want to confirm that the battery is in good condition, you may want to charge it first.

Check the Alternator

It is also possible to test the alternator of the car to ensure that it is working properly. Taking care of the battery charging system on an Impala, for example, involves the following steps:

  • The electrical accessories need to be turned off
  • The parking brake should be engaged, and the car should be in "NEUTRAL".
  • After implementing the No-Load Test, you should perform a Load Test.
  • Use the ammeter function on the Battery Tester.
  • Batteries are connected to the Battery Tester by connecting the positive and negative leads.
  • The current probe should be connected to the output lead of the alternator B+.
  • In cars with engines that run at 2000 revs, the alternator should be able to produce a greater output
  • Voltmeter settings should be set on the Battery Tester.
  • While connecting the positive lead of the voltmeter to the alternator's B+ terminal, ground the voltmeter's negative lead.
  • Electrical accessories should be turned off at all times.
  • When the engine is run at 2,000 revolutions per minute, the voltage should range between 13.0 and 15.0 volts.

Check the Other Components

Once you've checked the alternator and battery, make sure the rest of the battery charging system is operating properly as well.

A Serpentine belt inspection should be performed as part of your charging system check. The wiring should also be checked. Inspect the connections, terminals, and fuses to make sure they are in good condition. It is also important to ensure that the harness connector supporting the alternator is securely attached.


  • How much is it to fix a charging system?

Depending on your car's make and model, your location, and the component to be replaced, the price will vary. If you have to get help from a mechanic shop to fix your car's charging system, it may cost you somewhere between $250 and $1,000. DIY might also be more cost-effective since labor coats will be eliminated.

  • Can you jump a car with a bad alternator?

 The answer is yes. Despite having a bad alternator, it is possible to jump start a car. The jumper cables shouldn't be connected for longer than necessary, however, because they could damage the electronics of your car.

  • What maintenance is required for the charging system?

Once you know the right steps to take, maintaining your charging system won't be a problem. Listed below are a few of them.

  • Reduce corrosion: As a result of corrosion, current flows less freely through the electrical circuit. If your electrical connectors are corroded and have residue, you should clean them.
  • Reduce excessive draw of current: Keeping the engine running while listening to music can drain the battery's power. It is possible to drain the battery through such actions.
  • Inspect the drive belt: Check the drive belt to make sure it is not worn or loose. Make sure you replace it as soon as possible if it exhibits any of these conditions.

Final Words

Occasionally, you may need to service your battery charging system, as it is essential for the proper operation of your car. Therefore, it is necessary for you to understand how it works. How the system works is explained in this article, as well as what the battery/check charging system light means.

Your car's charging system may have been affected by some of these issues. If this occurs, what should you do, how should you check the charging system, and how can you keep your car's charging system in good working order?

Ever wondered what goes on behind the scenes in a car and how it is maintained? KeepDriving has more information on what causes black smoke from the car's exhaust.

Founder, Editor-in-Chief Carmelo Pickel is the Founder and Editor-in-Chief of Keep Driving, with almost 20 years of experience working in the industry. Before founding Keep Driving, Carmelo held leadership roles for over a decade on top automotive dealership corporations across North America, handling various leadership roles in Sales, Marketing, and Incentives.
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