Q: How Does the Alternator Work in Your Car?

asked by on

How does the alternator work in your car?

If the vehicle’s battery is the heart, its alternator would be comparable to its lungs. Both systems must work together to start and keep your vehicle running for years. The alternator is responsible for supplying power to all electrically powered components in a vehicle while the motor is operational. Before the engine starts, this responsibility falls on the battery. Once the driver turns the key and starts the motor, the alternator is activated and takes over for the battery.

How does an alternator work?

The alternator is typically installed in the engine compartment and is powered by a belt called the serpentine belt. In some cases, the alternator has its own belt called the alternator belt. When the engine spins over, a series of pulleys that are attached to the engine’s crankshaft are spun, which in turn spins the belt that is attached to another pulley on the alternator. The pulley attached to the alternator is connected to a needle bearing that spins around a series of metallic coils and generates electricity. There are also voltage regulators that control the amount of electricity produced. The electricity is distributed from the alternator to a series of relay switches, fuses, and connectors that supply power to components on the vehicle. The alternator is constantly working to generate electricity while the engine is running. Due to this fact, there are several factors that impact the lifespan of the alternator, which makes it very difficult to predict exactly how long it should last on a car, truck, or SUV. In some cases the alternator will work as long as you have the vehicle. In general however, the alternator should last anywhere from 50,000 to 100,000 miles on most domestic and import cars, trucks, and SUVs.

There are a few signs that might alert you that the alternator is wearing out, including: * The headlights seem dimmer than usual * Dashboard lights are not as bright as they should be * The ALT or GEN light illuminates on the dashboard * Accessories such as radios, AC and auxiliary switches don’t work as well

These symptoms are common with an alternator that is wearing out. If it breaks or the alternator belt is broken, the vehicle will quickly drain power from the battery and eventually shut the vehicle off or make it impossible to start. If this occurs, you’ll need to contact a local ASE certified mechanic and have them complete an alternator replacement or alternator belt replacement to get your vehicle back on the road.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. How Does the Alternator Work in Your Car?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Q: Charging system light on

Hi there. There is a possibility that your alternator or charging system may have experienced a failure. In the case of a charging system failure, the battery's charge cannot be kept and the battery drains during vehicle operation. Once the...

Q: Belt pulley fell off car

The moving components of the belt drive system use bearings to offer free smooth movement and reduce the effort necessary for the engine to drive the accessories. When the bearings fail, a pulley will often start to make noise or...

Q: Q: Headlights turn on by themselves

Hello. There are only two relays for the headlight control. There may be a problem with the headlight switch malfunctioning. Check to see how long you have the auto shut off timer set to, as it could be set for...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...