Skip the auto shop - Our mechanics make house calls

How a Battery Works With a Car's Electrical System

electrical system

Have you ever wondered how your car’s electrical system works? It all starts with your car battery.

Your car's electrical system operates on a closed circuit, with the main power system being the automotive battery. It uses less than the typical household current, and yet still manages to operate all the functions of your vehicle, including your headlights, window defoggers, turn indicators, aerial, fan, heater, washer pump, locks, sensors, and gauges, and more.

About your automotive battery

All that electricity flows along one cable running from your battery to the component that it powers, and then back to the battery through the metal body of your car. This is called a negative earth return system. That, essentially, is how car batteries work to make your car electrical system function.

What happens if your car battery voltage drops?

If the voltage drops, then your car's electrical system doesn’t work properly. You might find that your windshield wipers are sluggish, your windows don’t go up and down as quickly as they should, or even that your car is reluctant to start when you turn the key. That’s because some components will only work if they’re getting a high enough voltage.

The starter motor

Your battery also delivers electricity via a heavy cable to the starter motor. The starter is what activates your spark plugs, powers the alternator, and delivers power back to the battery.

This is a pretty simplistic explanation of how car batteries work with your car’s electrical system. The fact is that this is far too complex a topic to deal with in the space of this brief article. Modern cars can contain literally miles of wiring in the car electrical system, and this isn’t really a topic for a backyard mechanic, although it is a good introduction for someone who is curious about how car batteries work in the context of the whole vehicle.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...
P0291OBD-II Trouble Code: Cylinder 11 Injector Circuit Low
P0291 code definition When your vehicle’s PCM registers the P0291 code, it means that a voltage reading came from the fuel injector circuit – for cylinder number 11’s fuel injector –...


Related questions

Q: I have no idea what's wrong with my car

Hi there. From the description you have provided, there are many possibilities for your vehicle's drivability problems. It could be a fuel delivery problem, such as a faulty fuel pump not having the correct fuel pressure or no rest pressure....

Q: How can I clear previous calls from U connect on my Jeep Renegade

Hi there, thanks for writing in. Without knowing the year of your vehicle, it's hard for us to give you exact steps on how to complete this option. However, if you look inside your vehicle owner manual, there is a...

Q: Car battery dying quickly especially after longer driving

It sounds like the alternator is not charging the battery, when are you driving long distances. Running all the accessories and then shutting it off can cause the battery to be too weak to restart the car. If the alternator...