One parameter used in rating conventional automotive and other types of vehicle batteries is the cold cranking amperes (CCA). For a conventional automotive lead-acid storage battery, whose nominal voltage output is 12.6 V, CCA is a rating of the current (in amperes) that the battery can output for 30 seconds at a temperature of 0° C. with the battery voltage at or above 7.2 V. The CCA value relates to the capability of the battery for starting the vehicle. The most critical component of a vehicle that loads the battery is the vehicle starter motor. If the CCA is below a certain value, the starter will not turn over the vehicle motor for starting.
Accordingly, it would be desirable to know the CCA value of a battery already installed in a vehicle so as to be able to determine when the battery should be charged or replaced. A device manufactured by Midtronics of Burr Ridge, Ill. is available which measures battery CCA using an alternating current (AC) signal. This device is relatively expensive and complicated and requires that the battery be disconnected from the vehicle in order to determine its CCA value.
As seen, a need exists for a method and apparatus to determine the CCA value for a battery that is relatively inexpensive, easy to operate and can determine the CCA when the battery is installed in the vehicle without having to disconnect the battery. It also would be desirable to be able to provide a relatively inexpensive apparatus that can easily check the CCA value of a battery that is not installed in a vehicle, for example, where a battery is to be installed as a replacement or has been reconditioned.