The Basics About Your Car Battery

Automotive batteries play crucial role in powering your vehicle’s ignition system, accessories and electrical components. Knowing the basics about your car battery is an important first step in ensuring proper function and longevity.

Most batteries are a heavy, low-tech box of lead plates suspended in dilute sulfuric acid that triggers a chemical reaction. These plates are connected by short, heavy straps to a pair of external terminals.

Battery Type

The car battery is the heart of your vehicle, powering its engine and driving other electrical components. The battery delivers a burst of high electric current to start the car, then provides a steady energy supply.

It also functions as a backup in case the alternator fails. Car batteries come in a variety of sizes and configurations to meet your specific power needs.

Conventional lead-acid batteries use a lead plate and electrolyte solution to store and release energy. During the discharging process, a chemical reaction transforms the lead plate material into lead sulfate. The sulfate is then removed during charging.

The popularity of lithium-ion batteries is increasing. These batteries are found in EVs and HEVs and have a long lifespan with little to no maintenance required. They are lightweight, have a high energy density and offer quick charging. Research is continuing to lower the price and improve performance for these batteries. Sodium-ion batteries are another promising option and may eventually replace lithium-ion car batteries.

Battery Size

The battery size is the first characteristic to consider when buying a new car battery. It determines the physical dimensions of the battery (height x width x length), as well as where the positive and negative terminals are located. The battery’s group size also indicates its chemistry and Cold Cranking Amps (CCA), which is important if you live in a climate where winter temperatures can drop below freezing.

You can find the battery group size in your vehicle’s owner’s manual, or at any Firestone Complete Auto Care location. It’s important to know your battery group size because a battery with different characteristics won’t work in your vehicle. For example, a top-post battery won’t fit in a car that requires side-mounted terminals, and vice versa. Also, a battery with a higher CCA may not provide as much starting power in your car. It all depends on your unique needs and the performance requirements of your vehicle’s engine.

Battery Voltage

Car batteries are used to supply the power to run your car’s electrical systems. This power is measured by the battery’s voltage. The higher the voltage, the more power the battery can deliver.

Car battery voltage can be measured with a multimeter or voltmeter. Both are fairly inexpensive and easy to use. First, shut the engine off and remove the cover over the positive (+) terminal on the battery. It may unclip or lift off, or it could require a couple of bolts to be removed.

The battery’s resting voltage is about 12.9 volts. It will rise to a higher reading during the crank cycle, which is when the engine starts. After that, it will decline again. A low reading indicates the battery needs to be charged or replaced. The battery’s lifespan is also affected by age and usage. Its chemicals gradually turn into different ones that are less capable of providing power, and the voltage will drop over time.

Battery Life

Batteries live a complicated life under the hood. They need to handle heat, vibration and a grueling job description. Batteries have a limited lifespan, and they don’t offer many clues that failure is imminent. To make the most of your battery’s useful life, learn how to prevent some of the major issues that shorten a car battery and react quickly when you see the clues.

Like Goldilocks, batteries want the temperature to be just right. Extreme temperatures can kill a battery by slowing the electrochemical reaction that creates power. Long periods of inactivity also reduce a battery’s lifespan by allowing it to naturally self-discharge. Make sure your battery is getting enough use by recharging it after every drive and going for occasional longer trips to help recharge its capacity. In addition, regularly clean battery terminals to control corrosion and add distilled water when necessary. Using a maintenance charger can also help extend a battery’s lifespan.