5 Symptoms of a Bad Alternator
Generators are a critical part of any modern car. New vehicles have many electrical systems and components that need to be powered. The generator is the component that powers these electrical functions. Without a generator, you won’t have enough power to charge these electrical components.
Many people forget this important fact and simply think that the battery charges everything. In fact, your car’s battery only provides the power needed for the starter motor to start the engine. Once that happens, the generator takes over and powers all the electrical systems. It powers the headlights, air conditioning, power windows, radio, etc.
More importantly, the generator also powers the engine and engine control unit. Keep in mind that modern vehicles have electrical components in almost every area. All the sensors and computers in your vehicle are powered by electricity. A generator provides this electricity.
How a generator works
A car generator works by using mechanical energy to create electrical energy. It does this by using a belt-driven pulley to spin a rotor within a set of fixed coils.
As the rotor spins, it creates an alternating current (AC) in the coils. This alternating current is converted to direct current (DC) using a rectifier, which is then used to charge the car battery and power the car’s electrical components.
The generator powers most of the car’s electronic components, such as the headlights, dashboard instruments, power windows, power steering, wipers, heated seats, air conditioning, and stereo, while the engine is running.
It provides direct current to all these systems. Additionally, the generator is responsible for charging the car’s battery while it is running.
Common Symptoms of a Bad Generator Like a battery, a generator also gradually wears out over time. The more you use your car, the more wear and tear your generator will experience. The lifespan of an alternator in a new vehicle is 6-8 years for most people.
While you can’t tell when your generator will fail, there are warning signs you can look out for. These warning signs can easily be confused with signs of a low battery, which is why we’re going to explain the specific symptoms of a broken generator. 1) Low beam
If you are driving at night with your headlights on and notice that your headlights are dimmed, it means that your alternator is faulty. The generator is the main power source for your headlights. Therefore, do not assume that the battery is defective.
For safety reasons, stop driving immediately until it is light again. Then take your car to an auto repair shop and have them replace the alternator.
2) Car won’t start
If your generator is defective, all electrical components of your vehicle will be powered by the car battery. Even if your car battery is new, your car will not be able to drive around the block if the battery is the only power source for the electrical components.
If your generator is defective, all the energy will be drained from the battery. As a result, the battery will not be able to power the starter motor even if you try to start the engine. This means that your car will not start.
3) Warning Lights
A warning light or message will come on on the dashboard. The battery warning light can mean a variety of things, but on most vehicles it’s used to let you know there’s a problem with the alternator. The symbol is in the shape of a battery and can also have plus and minus signs.
Sometimes there’s a manufacturer-specific warning. For example, some Ford vehicles will have the message “Charging system, service please” and Mercedes-Benz vehicles will have the message “Battery/Alternator Workshop Visit.” In some cases, the “ALT” or “GEN” light will come on. 4) Electrical components stop working
Because the alternator powers your vehicle’s electrical components, you may notice that these components are no longer functioning properly. For example, if your air conditioner stops blowing air or your radio no longer turns on, these are signs of a faulty generator.
5) Abnormal noises
Generators contain many rotating parts. These components generate the electrical current needed to power all the other electrical components in your vehicle.
When a generator fails, some of the generator’s own rotating parts may become damaged or worn out. This creates a strange grinding noise, and may also make a squealing noise.
Can you drive with a broken generator? Normally you can’t drive very far with a broken generator. If your generator is broken it usually can’t charge the battery. The spark plugs need electricity to ignite the mixture. If your battery is empty just leave it be. How to diagnose a broken generator
There are a few tests you can use to diagnose a broken generator. Here are three easy tests you can do at home.
1) Check the alternator pulley
The easiest test is to make sure the alternator pulley is turning and that the belt is fine.
Start your car first. Make sure the alternator pulley is turning. If so, your generator has passed this test. It’s also a good time to check the belt for cracks or missing ribs.
2) Battery Voltage Test
First, grab a multimeter. There are many inexpensive multimeters available, but there are also some that are specifically designed for automotive use and make testing your car much easier. Set your multimeter to DC 15V or DC 20V. This setting will vary depending on the multimeter you use, but make sure it can measure up to 15V.
Power on the vehicle and turn on the multimeter. Turn on some accessories and load the generator. Next, connect the black and red wires of the multimeter to the multimeter according to your instruction manual. Connect the red cable to the positive terminal of the battery and the black cable to the negative terminal of the battery. If the generator can charge the battery, the multimeter should read 13.8 to 15 volts. This means that the generator passed this test.
3) Voltage Drop Test
The voltage drop test follows a similar process to the battery voltage test mentioned above.
Power on the vehicle. Connect the red wire to the live (positive) wire on the generator. Connect the black cable (negative) to the positive battery terminal. You should see a value like 0.08 or -0.08, or 8 millivolts (mV). A value this small means the voltage drop is very low and good.
Repeat this test for the negative cable. Connect the red multimeter cable to the generator housing and the black cable to the negative battery terminal. You should see a very small value again.
If you see a voltage drop of 0.2V (more than 200mV), try cleaning the battery terminals and alternator terminals. Simply cleaning these terminals may solve the problem without replacing the alternator.
You may see a larger voltage drop of 300mV or more. In some cases, you may see values ​​over 1 volt. This may indicate that the generator diode is faulty. In this case, you will need to replace the generator.
Check for excessive heat in the circuit
If you notice a large voltage drop, you can use an infrared thermometer to identify the problem. Point the thermometer at different points in the circuit.
You should be able to find a large heat spike near the source of the problem. This is because the additional resistance in the circuit converts the lost voltage into heat.
Bad Generators and Bad Batteries
Bad Car Batteries
A bad generator can cause similar symptoms to a bad battery. You can test if your battery is the problem by checking the battery voltage after fully charging it.
With the engine off, the battery voltage should be around 12.6V. If the battery voltage drops below 12V after driving for a while, consider replacing the battery. Lead acid batteries typically only last about 5 years before they begin to wear out.
If you notice corrosion on the battery terminals, clean the terminals before replacing the battery. If the battery terminals are not clean or tight, you may have problems starting your vehicle.
