Skip the auto shop - Our mechanics make house calls

Q: How Does a Battery Work With a Car's Electrical System?

asked by on

How does a battery work with a car's electrical system?

One of the most recognized mechanical parts under the hood of any vehicle is the battery. Whether you’re an ASE certified master mechanic or have never turned a wrench, everybody can pinpoint the location of their vehicle’s battery. Although most car, truck, and SUV owners know what a battery is, most may not be aware of how the battery works with the car’s electrical system to power multiple components that must work together efficiently in order to allow us to drive from point "A" to point "B" every day.

The battery is the primary source of energy that powers virtually all of the electrically charged components on a vehicle. Some of these components include:

  • Headlights
  • Starter
  • Heater / AC
  • Auxiliary systems (radios, alarm systems)

The battery of a car serves two main purposes: starting the car and powering the accessories while the engine is not running. Once the engine starts, the alternator (which is powered by a belt drive) takes over to power all of the vehicles accessories and electrical systems. At this point, the battery converts from power supplier to power generator and self-charges to maintain a level of amps and volts that will permit the battery to have enough power to engage the starter and start the motor once again.

The battery wears out over a period of time. This is due to the metal cells inside the battery and the acid/water inside the battery’s case losing their ability to generate electrons that helps the battery recharge. The battery will also lose a charge when the driver has electrical components left on without the engine running or if the alternator is damaged. When the car isn’t running or the alternator is damaged, the battery will bear the load of powering all of the electrical systems that need power.

Under normal operating conditions, a car battery should last anywhere from 3 to 5 years in most cases. Extreme weather conditions (both hot and cold), along with the driving habits of the car owner can reduce the lifespan of a battery.

The best way to avoid battery issues is to stay on top of routine maintenance, including having your battery inspected once per year by a local ASE certified mechanic. You can also avoid many battery-related problems by having a professional mechanic inspect or replace the alternator on your vehicle before it causes too much damage to your car’s battery.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
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 a Battery Work With a Car's Electrical System?

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: my daughter has a 2004 Toyota Highlander. the car wont start so i think it's the fuel pump since i can't hear it run. so once i ge

Check the fuse. There could be more than one relay in the circuit, for example a circuit opening relay as well as an EFI relay. The fault could be due to high resistance in the circuit (even at the relay...

Q: I was driving and my car started to slow down, and my gas pedal wouldn't work, and all the signs came on and the car light was flickering

Hi, thanks for writing in. It sounds like your battery has crashed. When the system voltage drops below a certain point, the electronics go haywire. The alternator is supposed to maintain the battery voltage at around 14 volts, and I'm...

Q: Just replaced fuel.pump and now it wont start

If both the starter motor and fuel pump are not working be sure the Engine Immobilizer is not active. If you are sure the security system is off and yet power does not reach the fuel pump or the starter,...

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 Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.