Automotive Battery Cold-Cranking Amp Temperature Adjuster By Bowling
The definition of the Cold-Cranking Amperage (CCA) of an automotive battery
is the amount of current a given battery can deliver for 30 seconds at
zero (0) degrees F without dropping below a specified cutoff voltage
(manufacturer-specific, but usually 10.5 volts). The value of CCA
will change with battery temperature, CCA increasing with higher temperatures.
The following derates a given battery CCA to ambient temperature. Inputs
are CCA in amps, the CCA rating temperature (usually 0 degrees F), and
the battery temperature in degrees F.
The CCA calculation is based on the following (from GM studies):
k1 = 0.61 + 0.0082*temp - 0.0000417*temp2
k2 = 0.61 + 0.0082*ccatemp - 0.0000417*ccatemp2
newcca = k1 * (cca/k2)