Understanding Car Battery CCA: Cold Cranking Amps Rating

January 27, 2012

In a car battery, CCA, or Cold Cranking Amps, is one of the most important means of classifying a battery and identifying the applications for a particular battery. Different cars, with different engines, may require a battery with different Cold Cranking Amp ratings. There are a variety of factors that affect the Cold Cranking Amps rating of a battery. There are also a number of factors that affect the Cold Cranking Amps that a given vehicle requires from a battery. The following paragraphs contain the basics of battery construction affecting battery CCA, factors affecting CCA requirements, and things you can do to ensure your battery is able to supply maximum CCA output and has a long life.

Battery Construction Factors

Automotive twelve volt batteries utilize a chemical reaction between lead-oxide plates suspended in a sulfuric acid electrolyte. These are divided into six separate sections, called cells, each of which produces two volts. By increasing the overall surface area of the plate/electrolyte junction, by such means as increasing the thickness of the plates, drilling holes in the plates, and creating grooves in the surfaces of the plates, the Cold Cranking Amps rating of the battery can be greatly increased. Another method some manufacturers employ to increase the amount of Cold Cranking Amps that a battery is capable of delivering is to employ a large number of very small grooved plates. These lead-oxide plates are sandwiched between separators to prevent short circuiting. Normally these separators are made of rubber compounds. In a car battery, charge is maintained, or held by these lead oxide plates.

Vehicle Cold Cranking Amps Requirements

Today’s modern vehicles and engines place great demands on automotive twelve volt battery systems. New vacuum controls and computerized engine diagnostic and control systems add to the demands placed on an electrical system. Larger and more elaborate passenger entertainment systems also place huge demands on a car’s battery. When the vehicle is running, the demand placed on the battery is greatly decreased. Demand placed on the battery is greatest when starting the engine. There are two main reasons for this. The first reason is that the ignition coil requires a larger spark than normal to start the engine. The second reason is the starter. There are a number of factors that affect how much demand, called starter draw, the starter places on the car’s twelve volt battery system. Factors that affect battery requirements are listed below:

  • Engine size-Engine size is the single greatest determining factor in CCA requirements. This is because a larger engine, with larger and heavier parts, thus more inertia, requires more energy to get it moving fast enough to allow the engine to start.
  • Cylinder head compression ratio-Compression ratio is a measure of how much fluid and gas pressure is generated inside the engine cylinders when the engine turns over. The higher the compression ratio, the more force is required to turn the engine over. The more force required to turn the engine over, the more CCA are required of the battery.

Knowing the various factors that affect CCA requirements will help you choose the correct battery for your particular application. The preceding paragraphs have given you information that will help you make that choice.

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