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 1,000 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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  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: After replacing the window regulator, and using the same motor, the window doesn't go all the way down.

Hey there. There is a safety limit switch that is built into the motor. You may have to check the window track or inside the door for something blocking the window regulator from going all the way down. You may...

Q: The battery keeps getting drained and dying out

Hello. It is possible that the your 2003 Lexus SC430's computer is draining the battery during the time that it is not being driven. It is never a good idea to let a car sit for extended periods of time...

Q: 2002 Dodge Ram radio and dome lights don't work

The IOD fuse is a 20 amp fuse located in cavity #51 of the integrated power module (IPM). This fuse provides power to the instrument cluster, diagnostic connector, map lamps, glove box, courtesy lamps, radio and underhood light. First, check...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...