AutoZone Starting & Charging guide - Batteries

AutoZone stores can charge your battery for free. We have a Duralast fast charger that can charge a 12 volt battery in about 30 minutes. AutoZone also offers overnight battery charging for 6 and 12 volt lawn and garden, motorcycle and marine batteries.

The battery has two main functions:

  • Supply power to the starter so that it can start the vehicle
  • Store electrical energy for running accessories in case of electrical system failure and/or when vehicle is not running

Different battery designs, which include type, size and power requirements, exist for every vehicle. For the battery to do an effective job powering your vehicle, the correct battery must be used.


1. Group Size: Size refers to the dimensions of the battery. It indicates length, width, height, and post configuration (which side the +/POS and -/NEG terminals are on). This ensures consistency among manufacturers the same way AA, AAA, etc. batteries are used for the batteries in your remote controls, flash lights, and so on.

2. Cold Cranking Amps (CCA): Cold cranking amps is the amount of power (amperage) that the battery can deliver consistently over 30 seconds in cold (0F) temperature. The higher the CCA, the better a battery will be able to perform in extreme weather conditions.

3. Reserve Capacity (RC): Reserve capacity is the amount of time that the battery can supply power to the vehicle when the key is off or the charging system fails. The technical definition is "the number of minutes a battery at 80 degrees can be discharged at 25 amps and maintain a voltage of 10.5 volts for a 12 volt battery". The higher the reserve capacity, the longer the battery will provide power before needing a charge and the longer the vehicle will operate on the battery power alone. This is an important factor to consider for a vehicle with accessories that require extra electricity such as light bars, winches, etc.

Note: Having the correct group size battery with more CCA and reserve capacity provides assurance to overcome potential electrical system problems. The higher CCA and RC you have, the better off you are when you encounter extreme conditions that might cause lower power batteries to fail.

How the Weather Affects Batteries

Heat is the number one cause of battery failure, and extreme heat can cause the water in a battery to evaporate. This can lead to corrosion of the internal components and battery failure.

Cold temperatures dramatically reduce the effectiveness of a battery. Electrons flow slower, reducing the amount of energy a battery provides. This results in a reduction of cranking power and sluggish starting. Batteries left in a discharged state are also susceptible to freezing, which damages internal components.

AutoZone can test your car's battery*, alternator, starter and voltage regulator while they're still on the car. We can also give your car a complete starting and charging systems test*. You can also bring your alternator, starter or battery into the store for testing. In most stores, we have the ability to test voltage regulators, control modules, coils, throttle position sensors (TPS) and other engine management components.
*Battery testing in-store only in California.
*Alternator, starter, voltage regulator, modules, and component testing not available in California.

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