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When Do I Need a New Car Battery?

In this instance, “Battery” refers to the small, square battery that sits under the hood or trunk of most cars. Usually, these are lead-acid batteries and they do everything from start the car (if it’s gasoline-powered) to run the accessories like the radio, wipers, and/or headlights and taillights. We’re not talking about a large lithium-ion battery that powers an all-electric car.

The more comfortable our vehicles become, the more stress we place on our batteries. It just stands to reason that with all the electronics to be found on a vehicle — air conditioning, climate control, infotainment systems, hybrid power drives, power-operated accessories — that a properly operating battery is even more critical to vehicle reliability. Stir in the higher and lower extreme temperature climates that we require our vehicles to weather, and you have a perfect environment for battery failure.

It is important to also note that all those accessories you plug into your vehicle’s USB and cigarette lighter power ports, those things that entertain you and keep you connected, also take a toll on battery life. Modern vehicles with cell phone charging pads (that automatically charge without cables) draw more power than cable systems, so while they’re convenient, know that they’re battery discharge points if the vehicle is not running. In the past, it was common for owners to leave headlights on or a door slightly ajar and later find their battery is dead.

New vehicles are smarter, both dome and headlights turn off after a certain period of time to avoid battery discharge. Ain’t technology grand?

How does a battery work?

Your vehicle battery provides the electrical energy necessary to start the engine and to provide “engine-off” (when the ignition is off) accessory power, when needed. Once the engine is running, the alternator takes over to power the accessories and recharge the battery. Vehicle batteries typically feature six connected cells in a lead-acid formulation, or up to 12 cells in a 24-volt system used in heavy trucks or other large vehicles. Know that even electric vehicles use a conventional battery to power accessories when the electric motor(s) that drives the vehicle is not operating.

How long does a battery last?

A quality battery, whether for truck, car or SUV, should ideally have a lifespan of approximately four to six years. Depending on extreme temperature climates (cold or hot), humidity, heavy accessory loads, and other factors that are detrimental to battery life, expect three or four good years from your factory or aftermarket battery.

What’s involved in maintaining or replacing a battery?

Batteries are not “one size fits all.” There are several things to consider. Also, car batteries are DANGEROUS. Be sure to wear eye protection and rubber gloves when handling a car battery.

  • Size: Typically based on your vehicle’s make, model and engine type, it is literally the dimensions of the battery, along with the positioning of the battery terminals that determine the battery for your vehicle. Every battery has a slightly different terminal placement to make it compatible with the battery cable position. Take care to make sure the new battery you’re putting into your car, truck or SUV is the same size and specifications as the one you’re replacing. In other words, don’t try to fit something that is close to right in the space reserved for the correct battery.
  • Age: Like most things, batteries are best when new. When shopping for a new battery know that it should not be older than six months from manufacture. Most batteries, like the one in your current vehicle, will have a date code to tell you this information. When in doubt, call the battery maker to decipher the date code.
  • Cold Cranking Amps: By far the most important specification to check when purchasing a battery is the Cold Cranking Amp number. Can your battery start your frozen SUV at 0-degrees Fahrenheit in the dead of winter? The higher the Cold Cranking Amps (CCA) rating, the better the battery’s starting ability. This rating refers to the number of amps a 12-volt battery can deliver at 0-degrees F for 30 seconds while maintaining at least 7.2 volts.
  • Reserve Capacity: In the case of an alternator failure, the reserve capacity rating will give you an estimate of how long your car’s battery can run on battery power alone, without the help of the alternator.

Key Point: Know that a faulty alternator can cause your battery to not recharge properly. Your dealer’s service department or your local auto repair center has the equipment to check the health of your vehicle’s alternator. We recommend having it checked every time you change your oil.

Replacing a car, truck or SUV battery

Replacing a vehicle battery can be a good project for do-it-yourselfers. Start by consulting your vehicle owner’s manual for the battery’s proper size and location. Identify the positive and negative posts and the cables that are to be attached to each. The positive post could have a red plastic cover over it. If there is corrosion or the cables look worn with wire sections visible, it’s time to enlist some professional assistance to repair these issues.

If everything is in order, start by loosening the negative (-) terminal bolt and removing the cable, taking care not to touch the positive post or any other metal surface – remember, a car battery discharges electricity. Touching the battery posts or other metal surfaces with a wrench or metal tool can cause sparks or an arc and this can cause the battery to explode.

When doing the work yourself, if the cable is not easily lifted or unscrewed from the point of attachment, a terminal puller may be needed. Follow this effort by repeating the procedure with the positive post.

Next, remove the clamp or retaining system holding the battery in place. Carefully lift the old battery to remove it from your vehicle. Batteries can be very heavy so be prepared since more than one person has hurt their back or smashed a finger performing this task. Use a terminal cleaning tool or a wire brush to clean any corrosion that may exist on the cable ends.

Position the new battery so that the red, positive post will match the positive cable’s location. Secure the battery with the battery-retaining clamp you removed earlier. Use of an anti-corrosion washer (a fabric disc that fits under the battery post) will help inhibit corrosion, Some DIY fans apply a thin layer of anti-corrosion grease to prevent buildup on the posts as well. Finally, tighten the positive cable and repeat the process with the negative cable. Recheck to make sure the battery is secured to its mounting platform, check that the cables are tight, close the hood and be on your way.

How much does it cost to replace a battery?

Regardless of the type of vehicle you drive, your local dealership service department, auto parts store or local automotive specialists offer battery replacements and check-ups to quickly replace your battery and have you on your way. Typically, prices range from $145 to $250, depending on power, size, and quality. In many cases, no appointments are necessary


Cam Benty
Cam Benty served as editor-in-chief for a number of automotive and sports-related publications early in his career, including Motor Trend Specials, Hot Rod and SPORT Magazine. After 20 years of experience creating monthly publications, he changed it up a bit, building custom publishing inserts and full-length specialty magazines for major car companies,including Ford, General Motors and Honda. A... Read More about Cam Benty

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