How do Car Batteries Work?

How do Car Batteries Work?


How do Car Batteries Work?
How do Car Batteries Work?


Without a car battery in excellent condition, your car won’t give the stellar performance you desire. You will keep having issues with your vehicle if the battery is weak.  A dead or a simply weak battery may leave you stranded in the middle of a road or even ruin other parts in your vehicle and that is something no one would like.

What is a car battery?

Car batteries run on chemical and electrical energy. There is an electrical circuit connected to the outside of the battery that charges the battery and allows electrons to flow. There are also chemical substances within the battery that form chemical reactions with each other and the electrons. Electrons act as the subatomic particle that activates the battery, allowing it to power up the car’s engine.

Most car batteries rely on a lead-acid chemical reaction to get things moving and grooving. These batteries fall into the “SLI” category. SLI stands for “starting, lighting, and ignition.” This type of battery provides short bursts of energy in order to power your lights, accessories, and engine. Once the battery jolts the engine to life, power for the car is supplied by the alternator. Most vehicles come with a generic SLI battery from the factory.

How does a car battery work?

There are three components within the battery, namely two connectors known as an anode and a cathode and then a chemical solution that the connectors sit in. An electrical charge from outside the battery charges it and activates a chemical reaction within the battery. The chemical energy is converted to electrical energy; thus, the battery powers up. The anode is a positively charged electrode within the battery, which allows the electrons to travel outside of the battery, and the cathode is the opposite, the negatively charged electrode through which the electrons re-enter.

Chemical reactions between the chemical solution within the battery and the anode and cathode each, is what allows the movement of electrons to occur. The electrodes are contained in the chemical reactions that occur between the solution and the connectors.

  • A typical SLI battery has six cells. Each cell has two plates, or grids: one is made of lead, the other of lead dioxide. Each cell is able to produce about 2-volts of energy. In most car batteries you have six cells, and therefore a 12-volt battery.
  • The plates are submerged in sulphuric acid that triggers a reaction between the two plates. In scientific terms, the acid acts as a catalyst.
  • This acid will trigger a reaction on the lead dioxide plate, causing the plate to produce two things: ions and lead sulphate.
  • The ions produced by the lead dioxide plate react to the adjacent plate to produce hydrogen and lead sulphate.
  • The result is a chemical reaction that produces electrons. The electrons race around the plates and generate electricity. The electricity flows out of the battery terminals to start your engine, turn on your headlights, and play the radio.
  • This chemical reaction is entirely reversible, which is why you can jumpstart your battery and continue to charge it throughout the duration of its life. By applying current to the battery at just the right voltage, lead and lead dioxide will form on the plates and you can reuse your battery, over and over again!

What are the main functions of a car battery?

Engine Starter

Providing the juice is actually a car battery’s first and the most important function. A battery stores chemical energy which later, when you turn your key or push the button to start the engine, is converted to electrical energy; a battery distributes it to all the parts in your car that may need it. While choosing a battery, you have to take into consideration the size of your engine and its displacement in order to pick the right one. If it’s too small, you will come across numerous problems in the future, especially those connected to starting your engine in bad (too hot or too cold) weather.

Helper to the ignition system

When you are starting a car, a battery does not only get your engine on and running, but it also starts the car’s ignition system. It links the whole vehicle’s electricity and turns its security features on. If there is something wrong with the energy system, that is the moment you probably find out. A battery also supplies the electricity to all the electronic devices when the engine is not running.


If a battery works as it should, it assures the sustainability of your car’s energy system. After you start your car, the battery gets recharged by an alternator to keep everything working when you drive; plus, it starts to store the chemical energy again to have enough to turn the car’s engine on the next time. The new-type batteries actually have systems that prevent them from getting all dried out of energy, as well as protect them from the corrosive damage for a longer time.


What is more, a battery transfers electricity to an alternator which, if it is working well, is responsible for such electric functions as the sound system, air-conditioning, the wipers, the headlights or even the airbag system – it basically keeps the car running after the start. Then, if there is any kind of malfunction or overwork of an alternator, a battery can act as a backup and keep you going for some time. A strong battery is needed especially when you decide to add some accessories to your car and they need electricity, for instance, additional lights or tools.

Voltage regulator

Sometimes other systems in your car can get overworked and produce high voltage spikes that normally would do a lot of harm to your car (they could even set it on fire). Fortunately, a modern battery can actually absorb some of the excessive voltage that other parts may generate. Thanks to that, all solid components and the whole electric system are protected from damage due to abnormal voltage level.


Do get your car battery checked from time to time, in order to ensure it is in good working condition!

Maintenance Tips for Long Car Battery Life

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Mobile Car Battery Replacement Davie, FL


Car battery replacement Davie, FL

2012-2021 Jeep Wrangler Starter Replacement


Autotech Mobile Mechanic

5410 W State Rd 84
Davie, FL 33314
United States (US)
Phone: 9548265523
Monday8:00 AM - 6:00 PM
Tuesday8:00 AM - 10:00 PM
Wednesday8:00 AM - 10:00 PM
Thursday8:00 AM - 10:00 PM
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