The correct comparison would be between conventional lead acid and AGM or starting vs deep cycle.Дeep Cycle batteries will typically have the higher AH and RC levels. AGM is the material used to create the battery and can be both deep cycle in nature and used in starting batteries. We get asked a variation of this question fairly often, 'should I get a group 31 AGM or a deep cycle group 31 battery?' It is a poorly formulated question asking us to compare different units of description that can partially describe the same item. At first glance you may think you own one instead of the other, so it is worth measuring your battery tray to confirm which battery you can truly fit. Typically the 27's will have 90 to 100Ah with a peak reserve capacity of around 190 for the best brands. The BCI Group 27 battery dimensions and specifications are very close to the 31's having the same width, but being slightly shorter in length and height. The dimensions should be roughly 12.90 x 6.75 x 9.25 inches. It depends on whether it is a thick plate deep cycle or thin plate stop/start battery or a dual purpose combination.

Generally speaking these batteries will range between 100 amp hour (Ah) and 130Ah, 600 cold cranking amps (CCA) and 1150 CCA and 150 reserve capacity (RC) and 230 RC. It can be overwhelming as you attempt to compare and decide what is the best brand and style for your application. Group 31 batteries are an extremely popular BCI group size. Battery Tender Plus, Junior & International.

Marine battery box group 31