Why Is My Car Battery Light on With a New Battery and Alternator

Published on: June 6, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

In the event of an issue with the charging mechanism, dashboard warning lights highlight this. This problem can occur even after changing your car’s battery and alternator. However, the battery may not be the problem. Often many users asked me, ‘why is my car battery light on with a new battery and alternator?‘ 

why is my car battery light on with a new battery and alternator

Well, an alternator or voltage regulator issue could be to blame for the car battery light on, but it could also be a problem with one of the charging cables. The battery stores the energy that the alternator produces. There will be a dead battery in your car if you have a bad alternator or the auxiliary belt that powers it is loose or broken.

You’ll see a charging system warning light when you first start the car, and that’s ok. But, if you see a battery warning light while driving then there’s an issue. So, in this case, you must know what to do when the dashboard battery light comes on. Here, I briefly explain why the car’s battery light came on even though it had a new alternator and a new battery.

What Is the Function of Battery and Alternator in a Car?

Each car has one or more 12-volt rechargeable batteries under the hood, and it supplies power to the starter to start your car. On the other hand, the alternator gives electricity to your vehicle’s electrical system after it is started.

The alternator, placed next to the engine, also recharges the battery, guaranteeing that it has enough power to start it when the car is switched off. Other parts such as power steering, air conditioning, and water pump operation are all supported by serpentine belts driven by your car engine.

The electrical system in your car has fuses to prevent over-voltage and short circuits. So you may be thinking, can a blown fuse cause the battery light to come on? Yes, it may cause a circuit’s current flow to be designed to “bust” the alternator, power steering pump, air conditioning, etc., and once blown, power cannot reach devices on that circuit that warn you by battery light to come on.

What Does the Battery Light Indicate?

If your vehicle’s charging system fails, the battery light will illuminate to let you know that your battery is no longer charging and must be operated solely on the power it still has. So it’s essential to know for a car owner what the dashboard’s battery light means? The light is activated when the alternator’s output voltage falls below a predetermined level, which is determined by a circuit that measures the voltage.

A benefit of employing an alternator is that it charges the battery more quickly. Generally speaking, the light signifies a problem with the battery. It is a sign that your alternator is functioning only on battery power if the indicator light comes on and does not go off as you drive. When your battery dies, your car will no longer be able to run.

Top Reasons a Battery Light Comes on With a New Battery and Alternator

If there is an issue with the charging system, the battery warning light will always be on. Most of us want to know “why is my battery light on after replacing the battery and alternator?’. There are many possible factors to look at throughout the diagnostic process when this happens. Below are some:

A Faulty Alternator Belt

For the alternator, engine, and other components to work properly, an alternator belt must be in place. Belts can fracture or break completely as a result of wear and tear. Misalignment, tightness, and a lack of elasticity are all possible causes. If a damaged alternator belt causes the battery warning light, it may also generate a screeching sound from the hood while the vehicle is in motion.

Loosened Battery Cable

The battery cables must be tightened down around the terminals to ensure a reliable connection. Hand rotation of the cable end around the battery post is not allowed. With pliers or a wrench, tighten the connection if it doesn’t seem to fit snuggly. To avoid breaking the battery bolts, be careful not to over tighten them.

A Faulty Battery Cable

The power from the battery is transferred to the vehicle via battery wires. These wires are thin yet strong to ensure that power is delivered safely to the car. Also a charger is another culprit of car battery light on. It’s wise not to use extension cord with a battery charger except in emergency situations.

Faulty Ground Clasp

In order for electricity to circulate around the car properly, a ground strap or ground wire is necessary. If the ground strap is broken or disconnected, the battery may not be able to be charged. When a ground strap becomes loose or rusty, you may notice a fault in a specific group of components.

Wiring Problems

The battery warning light may come on if any of the charging system’s many wires are broken or unplugged. In most cases, a wire will be severed near a connector rather than higher up in the wiring system, and age can stiff and brittle the wires and connections.

Using Too Many Gadgets 

An overabundance of the use of the vehicle’s accessories might deplete the battery’s reserve of power since the alternator belt powers them all. Hazard lights drain a lot of energy from these batteries. Some aftermarket sound systems may employ amplifiers that require more power than the alternator can supply. Adding a huge, power-hungry subwoofer usually results in this issue.

What to Do if Your Battery Light Comes on With a New Battery and Alternator

First, you should turn off all of your vehicle’s electrical systems except for the headlights to conserve the remaining battery charge.

The air conditioning, heating, audio, inside lights, heated seats, phone chargers, and Bluetooth accessories are all included in this package. So now you might be thinking ‘how do I turn my battery light off?’ In order to turn your car’s battery light off and figure out why the battery light is on, there are a few things you can do:

1. Check the Battery

Make sure your battery’s terminals are clean and free of corrosion or damage. Remove any decay and double-check that the terminal clamps are firmly in place. Make that the terminal clamps are in place and free of corrosion.

2. Examine the Alternator

Inspect your alternator for any loose or missing electrical connections. Because a bad alternator can ruin a battery

3. Check the Serpentine Belt

The serpentine belt is most likely to blame for overheating and loss of power steering. Inspect the belt for large cracks or breakages, as well as complete loss of the belt.

4. Inspect the Fuses

However, even if fuses don’t directly cause battery charging troubles, it’s important to inspect them and replace them if they are broken.

5. Examine the battery

Once you’ve completed these instructions, start your car and see if the battery is holding a charge. If the light goes out, you’ve probably figured out what the problem was. The alternator is most likely to blame if the light stays on.


1. What Does the Battery Light on a Car Mean?

The car battery light indicates a charging issue. A low voltage alternator may cause the light to turn on and stay on. Batteries with damaged cells or an alternator belt that has snapped are two of the most prevalent causes of these problems.

2. How Long Can You Drive With the Battery Light on?

If your battery light is on while you’re driving, you’ll have 30 to 60 minutes of driving time before your car starts stalling if your battery light is on.

3. How Can You Know if the Problem Is With the Battery or the Alternator?

Vehicles with dead batteries may have trouble starting, dimmer or flickering lights, or sound system issues. Alternators fail to recharge your battery if your car stalls while you’re traveling or if your motor suddenly shuts down without warning.

4. What Can I Do to Fix the Dashboard Battery Light?

Turn off all lights and other battery draining systems. If the issue persists, shut off the engine and let it cool. A technician should fix it if you didn’t do it. 

5. Why Does My Car Run With the Battery Light on?

If your battery light stays on and your car runs normally, you need to see a repair. Your car is depleting the battery’s remaining energy, and it will soon die.

6. Are there any specific warning signs to look out for?

1. Dim headlights that flicker or dim when the car is running, as well as when the car is off.

2. Battery or oil light on the dashboard.

3. A clicking noise when the ignition is on.

4. Slow cranking when starting the car.

5. An unexplained increase in fuel consumption.

6. A burning smell coming from the engine.

7. Unusual noises when switching on electrical components.

Are There Any Maintenance Steps I Can Take to Ensure?

1. Make sure to check the battery’s water level, and add distilled water when necessary.

2. Test the battery regularly to make sure it is holding a charge.

3. Make sure to keep the terminals clean and free of corrosion.

4. Replace the alternator belt if it shows signs of wear or cracking.

5. Make sure to keep the alternator and battery charging system free of debris and dirt.

6. Have the alternator and battery tested regularly by a professional mechanic.

Final Verdict

Following an oil and alternator change, if your car still has an issue and you might think, “Why is my car battery light on with a new battery and alternator ” then it may be a sign of a bigger problem. After reading this post, I hope that you better understand the various indicators and causes of car battery lights on.

After checking the symptoms, your battery light is still lit up!?? So it’s wise to see a technician in this issue. 

Featured image credit: cartreatments.com

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About This Writer

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Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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