Battery BCI groups

Battery BCI groups

Most batteries are refered to as an “group XY battery”, there is a number like 24 of 27 at the spot of the XY. This only tells something about the dimensions of the battery and has nothing to do with Ah (Amp-hour) rating or CCA (Cold Crank Amps, applies to starter batteries). The capacity usually rises when the battery gets bigger so there is some logic.

 Deep cycle 12V batteries

deepcycle-12v-27

Battery BCI Group Size (LxWxH) Capacity (Average)
Group 24 11.3″ x 6.8″ x 8.9″ 80Ah – 90Ah
Group 27 12.1″ x 6.8″ x 8.9″ 90Ah – 100Ah
Group 31 12.9″ x 6.8″ x 9.2″ 125Ah – 150Ah
Group 4D 20.5″ x 8.5″ x 10.0″ 200Ah – 250Ah

Other popula groups like for example 25, 34, 35 etc are all starter batteries used in cars.

Deep cycle 6V batteries

deepcycle-6v-gc2 deepcycle-6v-l16

Battery BCI Group Size (LxWxH) Capacity (Average)
Group GC2 10.4″ x 7.1″ x 10.9″ 200Ah – 225Ah
Group L16 11.7″ x 7.0″ x 15.8″ 340Ah – 400Ah