PCA (Pulse Crank Amps) is a rating specifically geared towards starting applications or high loads for very short duration loads only. In short, PCA can be thought of as HCA (hot cranking amps) for a brief measurement of time. Pulse Cranking Amps (PCA) more closely represent the type of conditions we experience in the average vehicle start. (PCA) rating does not have an “official” definition; PCA is a very short duration (typically less than 5 seconds) high rate discharge. Because the discharge is for such a short time, it is more like a pulse of current.
At this time all of Braille’s ratings are determined by using a conductance tester and calculations based on real world performance in actual conditions. For more information on Conductance Testing, please see this link: Conductance Testing Method