Battery Light On But Alternator Is Charging – Things You Need To Know

It is very easy to encounter unexpected problems with automotive vehicles. These problems can be a damaged battery, an alternator failure, or damage to the vehicle’s gear.

Currently, the battery light on but alternator is charging is an issue that confuses many drivers.

Lucky for you, in today’s article, we will provide you with useful information such as why such errors appear and how to fix them.

The Reason Why Alternator Is Charging But Battery Light Is Still On

The car lights will come on and then turn off when you start the automotive. This process is always working at regular intervals as it is a system to check the electric lights and the charger components.

If the light is still on, there must be an error. The error can be some of the most common conditions you often encounter, including dim headlights, air conditioning not working, or a faulty accelerometer.

To figure this out, we’ll go through the symptoms of both a bad battery and a bad alternator.

Battery

The average life of a 12V battery usually lasts 3 to 5 years. Although many manufacturers often promise impressively long battery life, it’s wise not to have high expectations for their marketing tricks.

Batteries currently on the market have a lead plate made of dioxide, and the lead plate is completely submerged in a sulfuric acid electrolyte solution.

This lead plate can break over time, and the electrolyte solution may leak out. And when this problem arises, the first thing you need to do is replace the corroded battery with a new one.

Alternator

For a generator, the minimum voltage should be 13.6V or 14.6V maximum.

When this number does not reach 12V, the warning light system will turn on, and you must immediately replace it with a new one.

Conveniently, you only need a multimeter to check this parameter.

Moreover, there is another cause of the alternator charging, which is the voltage regulator.

The standard safety rating is 14.5V, but if it’s not working properly and the reading exceeds 14.5V, it can also cause the indicator light to turn on.

Cracked Belt

Belts connect the generator, engine, and other accessories in an automobile. It is an extremely important element because none of the critical components will work if there is a problem with the belts.

Possible problems include loose/tight cords or complete breakage.

Additionally, besides being the cause of the constant flashing of the car’s flashlight, it can also cause the squeaking noises in the hood when moving.

Corroded Terminals

Car battery corrosion on the terminal

Battery terminals ( both negative and positive) load the battery into the device.

Therefore, we should not coat them with poor conductors that can, unfortunately, increase the resistance of the electrical flow, thereby reducing the ability to receive and transfer current.

After using it for a while, corrosion will appear. They are white or blue plaques on the surface of the device.

Corroded equipment often loses its original capacity and leads to poor speed and power levels.

Loose Cable

When placing the batteries in the generator, you must ensure that its terminals are properly fitted. This will supply the vehicles with the right amount of electricity for proper operation.

Note that you cannot rotate the upper ends of battery cables by hand if there is a mistake.

When you find a loose spot, use a wrench to tighten it. However, some bolts and screws will come loose if applied too much force. As a solution, try not to use too much force.

Broken Cable

In addition to the problem of being loosely positioned, cables can also break for many different reasons.

With a bad cable system, your battery won’t be able to charge. Uncharged power will leave your vehicle without the energy to move.

Wiring

In a car, the wiring harness is the most prone to damage. Over time, these wires become stiffer and more brittle, leading to complete breakage.

Most significantly, they are the components most involved in the vehicle’s charging system. So, when a wire is broken or disconnected from the power source, the lights will glow to warn you of the issue.

Working Accessories

All car accessories are connected to the vehicle via belts. These devices oftentimes can use up quite a lot of your car battery.

Therefore, overuse of these working accessories can also lead to rapid battery depletion.

More specifically, the sound system is the most problematic electrical accessories. With devices capable of amplifying sound, the power consumption is even more than any other device.

What To Do If Battery Light Came On But Alternator Is Charging

Frequently Checking Car System

Prevention is better than cure. It would help if you did not wait until the car has a problem to have it repaired as that will cost you a lot of money.

Make it a rule to always check your vehicle thoroughly before moving. In case you can’t do this every day, do it at least twice a week.

Experts often recommend taking your automotive to a service center or an auto shop for repair and inspection.

The ideal schedule for your regular car checkup is about once a month. Depending on the model, age and condition, the examination time will also be affected.

Finding Out Problems

Your newly replaced alternator is charging but battery light is on. Then, you need to find out the accurate underlying cause to fix your beloved vehicle immediately.

You should not ignore this detail because one minute of delay can cause you regrets later.

A common cause that you may come across is the engine system. When there is a difference in fuel, the non-combustible gasses will become vapor and produce an unpleasant odor.

This can be considered a potential cause that the light is still on after replacing the generator.

However, the best practice is to check continuously for other possible causes that might contribute to your alternator issue.

Troubleshooting Issues

Besides using your vehicle with care, you should also take good care of your car by managing the repair and maintenance of your car.

Daily inspection of the vehicle and learning how to fix it through car manuals are the simplest ways to examine and troubleshoot problems.

This troubleshooting knowledge includes knowing how to change a tire or realizing when your automobile needs professional care.

Alternator Test

In generators, diodes are electrical components. Once this device fails, it causes the whole machine to malfunction.

In addition, once the diodes fail, other parts of the machine, such as the rotor shaft, bearing, and gear, also cease to work properly. A clear indication of this problem is unnecessary noise while moving.

You can easily fix this issue by looking closely at the generator and listening to the sounds it makes.

When you hear whining noises, your diodes are likely either faulty or overcharged.

On the other hand, if you hear grinding noises, this means the bearings and bolts are loose, causing the gears to not match as they run.

Checking Voltage Charge Level

This problem requires you to have very precise testing equipment. We recommend using a digital multimeter (DMM) or a power load meter.

These devices will allow you to determine if your battery voltage charge is overloaded or drained.

We will elaborate more on how you can conduct the voltage charge level test below:

  • Try starting the engine and let the speed reach 1500 rpm.
  • The test equipment should reach a figure of 0.5 to 2V above the base voltage.
  • If the reading exceeds the 2V threshold, your car has a problem, or the charger is overloaded.

Common Symptoms Of Bad Alternator Systems

The alternator is a device that plays an important role in a car’s electrical system. It generates energy to operate and recharge the vehicle’s battery. Therefore, when it crashes, many problems follow in a chain effect.

So, how to know when the generator shows signs of failure? Here are six major alternator symptoms that you can easily identify.

Battery Indicator Light Stays On

When you detect that your vehicle is flashing Alt or Gen, it means that your automobile is equipped with an indicator light system. However, this is the first sign that your car’s charging system has serious problems.

Therefore, you should not take this error lightly. We recommend that you take your vehicle to the nearest repair shop so the professionals can take a look and get your vehicle back to normal.

Dimming Headlights/Lights

Headlights are a good place to check if your car has a power problem. There are many simple tests you can do at home to verify this.

Specifically, whenever the headlights show signs of flashing or dimming for a long time, they clearly indicate a faulty alternator.

Battery Failure And Quick Consumption

It might be complicated to explain why alternator is charging but the battery light is on.

There is a chance that the problem does not stem from the generator at all. Sometimes the batteries installed in the car may have been damaged beforehand.

When the power source works continuously but cannot recharge itself through the electrical energy, it will slowly run out of power.

Stalling Or Difficulty In Starting

Besides running on gasoline, electricity is also a source of mechanical energy that helps your car operate.

The mechanism behind this system relies on the fact that spark plugs are affected by an electric current that can ignite, thereby igniting the gasoline inside.

When a generator fails, the current may not be strong enough for the spark plug to operate, causing the vehicle to stall or become inoperable. 

Noises Under The Hood

Sound is a sign that few people pay attention to because they assume this type of device can produce strange sounds.

Therefore, we often do not pay attention to this influential symptom. Fortunately, it has been confirmed that the generator is often the main cause of this condition.

However, do you know what kind of noises to look for? During operation, bearings or gears in an engine that are not powered by the alternator may be affected, which leads to abnormal chirping noises.

Electrical Failures

The broken generator will cause many other electrical devices in the car to fail over time. Accessories that can be damaged include a power window, control panel, radio, or air conditioner.

It is advisable for you to go to a professional mechanic if you encounter this problem.

FAQs

Is It Safe To Drive A Car When Battery Light Is On?

To be frank, it is problematic. When the car’s charging system has a problem, the car can certainly shut down suddenly on the road.

In some situations, your car may stall, and you might be stranded in the middle of nowhere if you cannot find a way to jumpstart the car.

In essence, it is absolutely not safe for you to drive with the battery light flashing simultaneously. We recommend taking your automotive to the auto repair shop for a complete checkup as soon as possible.

Is It Necessary To Replace The Battery Or The Alternator?

You should note that damaged batteries might not be a big deal, but it’s bound to fail over time if a bad generator accompanies them.

Both are two devices that support each other to make the vehicle run smoothly.

According to market prices, a standard battery ranges from $50 to $120. Meanwhile, it will be a lot of money if you consider replacing your generator with a new one. Including labor, the cost can hike up to 1000$.

Will A Bad Alternator Destroy The Battery?

The alternator is the tool for generating and storing energy in the vehicle. As mentioned above, a broken generator will lead to many troubles, including battery damage.

This is because both support each other to make the vehicle run smoothly.

If this situation persists, your battery will gradually degrade. Sadly, it will come to a point where all you have left is a pile of scrap metal. Therefore, it is crucial to take good care of your vehicle in your everyday use.

Conclusion

After reading this blog, hopefully, you can answer the question “why battery light on but alternator is charging” all by yourself.

It would be unwise to insist on driving your car out when problems could arise suddenly, and you will harm yourself as well as other road users.

In conclusion, the best advice is always to pay attention to checking and maintaining your car in the best way because vehicles always have problems that no one can foresee.

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