When does a Car Battery need to be Replaced?

The main function of a car battery is to start your car. Today, most cars have a single maintenance-free 12-volt acid battery

A car battery is rechargeable. It uses its charge to power the vehicle systems while it’s parked and to turn over the engine when you want to start it. Once you start the car, the alternator generates additional electric power to recharge the battery. Read more about recharging below.

Over time, a battery loses its capacity or ability to hold charge. One day, a weak battery will not be able to start your car. Often, this happens when the weather gets cold. When the battery is low on charge, a car will need to be boosted to start. To avoid this situation, a battery should be replaced before its capacity drops to a critical level.

On average, a car battery lasts from 5 to 7 years. The battery lasts longer if the vehicle is driven daily and the battery is kept fully charged. When the vehicle is parked for extended periods of time, the battery deteriorates sooner. We have seen the battery lasts up to 10 years. Several car owners commented on our FB page that their battery lasted for over 11 years.

How can you tell that the battery capacity is getting low? One way is to have it tested.The battery capacity is often measured in CCA or Cold Cranking Amps. Many automotive repair shops can test your battery with a special tester (in the photo). The battery tester can measure the actual CCA and compare it to the new battery CCA rating. A battery tester can also test the alternator and the charging system.

The battery and charging system test, known as the AVR test, costs from $20 to $50. Some auto parts stores such as Autozone or O’Reilly Auto Parts offer a battery test at no charge. Many car dealers and repair shops often offer a free battery test as a part of seasonal promotion. After the test, you might get a printout, showing the battery CCA rating and actual CCA. The printout will indicate if the battery should be replaced or just need to be recharged.

Are there any signs that a car battery is failing? Yes. When the battery is weak, you might notice that the engine turns over slower than usual and the dash lights flicker or go dim when you are starting your car. This happens even if the battery is fully charged after driving.

Another sign is when you operate your power windows after the engine is turned off, the windows move much slower than when the engine is running. You also may notice that the headlights are dim when the engine is idling, but become brighter when the engine is revved. Often you will also see excessive corrosion at the battery terminals and cables when the battery is getting weak. A fully charged battery should read 12.6 Volt or more. Testing the capacity of the battery with a voltmeter is more difficult. One way is to test the voltage of the battery under the load, for example, with the headlights on. If the battery voltage with engine off and headlights on drops from 12.6 Volt to less than 11 Volt in a couple minutes, the battery is weak.

Many dealers and reputable repair shops visually inspect the battery terminals during regular oil changes. Your mechanic may recommend servicing battery terminals if they are corroded as in the photo. The battery terminal service costs from $25 to $50. It includes cleaning the battery posts and terminals and applying a protective spray or grease.

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