Contrary to popular belief, the car’s battery is not only source of power for any of its electrical systems. The alternator is essential for starting the vehicle, charging the battery, and powering the air conditioning system.
A malfunctioning alternator causes the battery to discharge rapidly, which can cause your car to stall. But we will find out what can go wrong and why battery cannot be charged.
Alternator not Charging Battery – 7 Most Common Reasons
If your car charger stops charging your battery, this is the same time as your car not starting. However, if you are lucky, in some cases your car may run for
about 15 minutes but then the power may suddenly go off. Knowing the cause can help you diagnose and possibly fix the real problem.
- Worn brushes
- Damaged alternator
- Faulty Fuse
- Broken Serpentine Belt
- Wiring Issues or Connectors
- Damaged Car Battery
- Engine Control module error
1) Worn Brushes
An alternator that is worn out or damaged is the most frequent cause of a car that isn’t charging the battery. If the voltage is within the charging range, you can check if with a hammer while the engine is running.
When you lightly tap the voltage with a hammer while the car is running, and it returns to normal, the alternator’s carbon brushes are worn out and need to be replaced. As an alternative, you could swap out the alternator for a new one.
2) Damaged Alternator
The alternator may occasionally have an electrical issue, and even if the voltage remains constant, it may sustain damaged diodes are two more frequent causes. Generally speaking, replacing either of these calls for more advanced alternator knowledge.
On old cars, it was more common replace parts inside the alternators are now fairly inexpensive, replacing the entire is typically less expensive than fixing an internal alternator issue.
3) Faulty Fuse
The large power cable of the alternator is frequently connected to a massive fuse. It is typically located in the fuse box located in the engine bay of your car and is typically an 80 amps fuse or greater.
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Fuses either wear out or burst from a power surge. The alternator will stop producing current at that point. The fix is to find the specific fuse that regulates the alternator in your car’s handbook and replace it. Some cars may also have a second small fuse, usually a 15A to 20A fuse, for the alternator.
4) Broken Serpentine Belt
Upon closer inspection, the alternator is made up of a belt and pulley system that transforms mechanical energy into electrical energy. The alternator is driven by the serpentine belt. If it malfunctions, the alternator will cut off as soon as the pulley sustains damage or your belt wears out and breaks.
This may also occur if the serpentine belt is not properly tightened. Although automatic tensioners are found in most cars, it is still advisable to check them twice. In the event that your older car has a manual tensioner, you may need to tighten the serpentine belt. Replacing the pulleys and serpentine belt is frequently quite simple and affordable.
5) Wiring Issues or Connectors
Usually, an alternator with three or four wires attached to it is operating properly. One large main cable and two or three smaller ones are included. The alternator depends on each of these wires to operate, and if one breaks you may not be able to charge. Make sure there is no corrosion on the large power cable connectors that connect the alternator to the vehicle battery.
If there is a problem with any connection, the cable will typically become warm. Examine or gauge these cables using a multimeter. Keep in mind that testing wires that are partially broken or have a poor connection requires you to load them, so measuring them is not always accurate. On these wires should normally be receiving 12 volts, and the other wire should be going to the dashboard’s battery light. It does frequently go to the engine control unit if you have a third one. You will a need a wiring diagram specific to your car model in order to measure this correctly.
6) Damaged Car Battery
The car’s battery and alternator cooperate well. An extremely damaged vehicle battery may not accept any voltage from the alternator at all. In this instance, the cause of your issue is the battery rather than the alternator.
A car can theoretically run solely on the power from the alternator, but this can result in high voltage spikes and other odd symptoms, so it stands to reason that a malfunctioning car battery could also prevent the alternator from charging.
7) Engine Control Module Error
Modern electronics are being added to cars more and more. In this sense, the majority of the electrical components in the car are managed by the engine control unit (ECU). The alternator in modern cars is also controlled. Rarely, there may be a problem with the engine control module not managing the charging of the alternator.
To fin out if there’s another damaged component preventing if from charging, use an OBD2 scanner to check for any trouble codes. Rarely, an actual malfunctioning engine control unit may exist. However, you should always rule out any other potential reasons.
Symptoms of A Bad Alternator
To learn symptoms of a bad alternator the whole purpose of the alternator is to charge the battery and it runs electrical components in your but for this to happen the car has to be on now the location of the alternator depends on the car.
This Toyota had the alternator towards the front of the engine, this Suzuki had the alternator towards the left of the engine and this ford fusion had the alternator towards the front of the engine the average life expectancy for an alternator is 100 to 150, 000 miles. So, if your cars about that range then look out for these symptoms the first symptom you might be experiencing.
- Warning Light
- Noises
- Headlight Problems
- Engine Stalling
- Accessory Failure
1) Warning Light
Is a warning light different cars have different warning light an alt or a gen light the second symptom you could be experiencing.
2) Noises
Are odd noises if you hear a grinding noise this could be the bearings going of your alternator. If you hear squealing noise maybe it’s time to look into your serpentine belt a bad serpentine belt can be the reason why your alternator is not working properly.
A worn belt can have less traction to rotate the alternator causing the same symptoms as a bad alternator.
3) Headlight Problems
During night time driving you’ll be able to notice your headlights are dim also if you’re just driving down the road and you just see the headlights just flicking like turn off and on really fast that’s a good indicator.
4) Engine Stalling
Your car will literally just stop in the middle of the road and it will turn of and you’ll be wondering that happened. I don’t get it and if you are lucky, it’ll be able to turn on and you will be able to go to the grocery store and back to your home.
Now in order for a car to run you need air spark and fuel, now since fuel and spark is controlled through electricity. Which comes from the alternator that charges your battery that’s not working nothing working.
How to Diagnose & Fix Alternator not Charging
To make sure your alternator is operating properly, there are a few simple steps you can follow. While the engine is running, gently tap the alternator with a hammer. The charging resumes normal, the carbon brushes inside the alternator are worn out and require replacement.
Examine the large power cable leading to the alternator and the large 40-to-60-amp fuse that is typically located close to the battery. Examine the ground cable that connects the engine and body. Verify that the alternator is spinning in tandem with the engine by checking the serpentine belt.
Examine the wires leading to the charging light and the tiny power supply. A multimeter can be used to measure it, but accurate results may require the use of a wiring diagram and some knowledge of automotive electronics. To make sure the voltage regulator and the diode assembly are undamaged, you can measure them. Certain alternator can be used in their place, but buying a new alternator these days usually costs the same. What you believe to be more worthwhile is up to you.