When purchasing a battery, you will see a series of numbers and letters in the name. These numbers and letters are the BCI group size of the battery. BCI stands for Battery Council International. This is a trade association that includes manufacturers, recyclers, distributor, and retailer organizations that supply original and after. First, each vehicle comes with a specific battery tray size, whether it's a car, truck, SUV, commercial vehicle, boat, recreational vehicle, or. BCI is the most common system used to classify battery group sizes. The following battery group size chart explains the most common BCI battery. The BCI designationsinclude the group definition, dimensions, measurements, types, sizes, and other characteristics. The battery conversions chart can help you to cross-reference battery. When choosing a battery, it is important to use the ones that are recommended by the manufacturer for your make and model of the vehicle. The easiest way to find out what battery group you. This is a list of the sizes, shapes, and general characteristics of some common primary and secondary in household, automotive and light industrial use. The complete nomenclature for a battery specifies size, chemistry, terminal arrangement, and special characteristics. The same physically interchangeabl.