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How a Car’s Battery, Starter, and Alternator Work Together

“Why won’t my car start?” While many drivers immediately assume they are facing a dead battery, it could be an issue with your battery, starter, or your alternator. The professional mechanics at Chapel Hill Tire are here to unpack how these systems work together to power your car’s electrical components. 

Car Battery: How Does a Car Battery Work?

Let’s start at the beginning: what happens when you turn the key (or push a button) to start your engine? Your battery sends power to the starter to get your vehicle running. 

Your car’s battery has three responsibilities:

  • Powering your lights, radio, and other vehicle components when your engine is off
  • Storing power for your vehicle
  • Providing the initial burst of power needed to get your engine started

Starter: A Quick Overview of the Starting System

When you switch on your ignition, the starter will use an initial burst of power from the battery to fire up your motor. This motor puts your engine in motion, kickstarting all of your vehicle’s functioning parts. An essential power component among these moving parts is your alternator. 

Alternator: The Powerhouse of Your Engine

When your engine is turned off, the battery is your car’s only source of power. However, once the engine starts moving, your alternator provides the majority of the electrical power supply. How? While it is a complex system of moving parts, there are two main components at play:

  • Rotor—Inside your alternator, you can find a fast-spinning rotor of magnets.  
  • Stator—Along the inside of your alternator, there is a set of conductive copper wiring called a stator. Unlike your rotor, the stator does not rotate. 

Your alternator uses the movement of your engine’s belts to turn the rotor. As the rotor’s magnets pass over the stator’s copper wiring, they generate electricity for your vehicle’s electrical components. 

Not only is your alternator supporting your vehicle’s electrical functioning, but it is also recharging your battery. 

Naturally, this also brings us back to your starter. By maintaining the charge in your battery, your alternator ensures the starter has a reliable source of power any time you are ready to drive. 

Why Won’t My Car Start?

Each of these vehicle components has multiple parts at play—all working together to power your vehicle:

  • Your battery powers the starter
  • The starter kickstarts your alternator
  • Your alternator recharges the battery

While the most common issue here is a dead battery, any interruption in this process can prevent your vehicle from starting. Here is our guide to determining when you are due for a new battery

Chapel Hill Tire Starting and Charging System Checks

The local auto repair and service technicians at Chapel Hill Tire are here for all of your vehicle’s battery, starter, and alternator needs. We offer everything from alternator replacement services to new car batteries and everything in between. Our experts also offer a starting and charging system check in our diagnostic services. We will check your battery, starter, and alternator to find the source of your car troubles. 
You can find our local mechanics in our 9 Triangle-area locations across Raleigh, Apex, Chapel Hill, Carrboro, and Durham. We invite you to make your appointment here online or give us a call to get started today!

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