Get High on Cranking: Car Battery Specs StickerNumbers Explained

Car battery specs conform to standards developed by the Battery Council International (BCI) and the SAE.

- Marlan Davis

Many of the specs appear on the battery label as well as in battery manufacturers’ published literature. For car guys, the most important specs are:

•Cold Cranking Amps (CCA): The discharge load in amperes that a new, fully charged battery can deliver at 0 degrees F for 30 seconds while maintaining a voltage of 1.20 volts/cell or higher. This measures the battery’s ability to start (crank) an engine under low-temperature conditions where the chemical reaction inside the battery slows down: A battery puts out 100 percent of its rated power at 80 degrees F, 65 percent at 32 degrees, and only 40 percent at 0 degrees. CCA is great for comparing battery performance in cold climates, but in hot climates lead-acid batteries with extremely high CCA ratings may actually have a shorter life than those with lower ratings: Within a given overall battery case (group) size, upping the CCA requires thinning out the internal plates to squeeze more out of them within the same case volume. Thinner plates are more susceptible to vibration and overheating.