BCI Group 24 vs Group 27 Battery

BCI Group 24 batteries and BCI Group 27 batteries are very similar batteries in terms of dimensions, battery types, chemistry, and in the end, their intended use.

However, these batteries are not exactly the same and they should not be used interchangeably unless explicitly permitted by the manufacturer of the intended application/service/tool.

Published: July 20, 2021.

BCI Group 24 Battery Dimensions

BCI Group 24 batteries feature dimensions of (L x W x H) 10.25 x 6.8125 x 8.875 inches (260 x 173 x 225 mm), but there are other subgroups present as well:

As one can see, BCI Group 24 batteries differ in length and height. However, they also differ in chemistry, battery type, terminal type and orientation, and similar - when looking for a new battery, be sure to check the actual battery size, type, chemistry, terminal type and orientation.

Note: this goes not only for the group 24 batteries but for all battery sizes in general.

BCI Group 27 Battery Dimensions

BCI Group 27 batteries feature dimensions of (L x W x H) 12.0625 x 6.8125 x 8.875 inches (306 x 173 x 225 mm), but there are other subgroups present as well:

BCI Group 27 batteries also differ in length and height, just like group 24 batteries.

When comparing group 24 and group 257 batteries, "standard" group 24 and group 27 sizes are used (L x W x H):

- Group 24 dimensions: 10.25 x 6.8125 x 8.875 inches (260 x 173 x 225 mm),

- Group 27 dimensions: 12.0625 x 6.8125 x 8.875 inches (306 x 173 x 225 mm).

The actual difference in size between groups 24 and 27 is 1.8125 inches (46 mm) in length, while the width and height are the same (W: 6.8125 inches (173 mm), H: 8.875 inches (225 mm)).

Because of this difference, battery compartments intended for the group 27 batteries may accept group 24 batteries, while the battery compartments intended for the group 24 batteries generally cannot accept group 27 batteries.

And because of the larger volume of the group 27 batteries, group 27 batteries feature larger capacity, and better CCA, MCA, and RC ratings.

Most Popular Group 24 and Group 27 Batteries

The following comparison chart lists some of the most popular group 24 batteries:

Note: Amazon links in the table open in the new windows ('Model' column), so feel free to check them for the most up-to-date prices and offers.

On average, group 24 batteries are mostly deep cycle batteries with nominal (20h) capacity of 75-85 Ah, Reserve Capacity of 140-180 minutes and they weigh 43-57 pounds.

Most group 24 batteries are not intended for high-current applications, but some models feature a CCA rating of 500-840 Amps and an MCA rating of 625-100 Amps, allowing them to be used even as starting batteries for smaller gas and diesel engines.

The following comparison chart lists some of the most popular group 27 batteries:

Note: Amazon links in the table open in the new windows ('Model' column), so feel free to check them for the most up-to-date prices and offers.

On average, group 27 batteries are mostly deep cycle batteries with nominal (20h) capacity of 80-110 Ah, Reserve Capacity of 170-220 minutes and they weigh 64-68 pounds.

While most group 27 batteries are deep cycle batteries, there are also several true dual-purpose batteries, including Optima D27M with spiral wound cells and NorthStar NSB-AGM27 with flat-plate cells.

Because of the spiral wound cells, Optima D27M battery is somewhat lighter than other group 27 batteries and features a relatively modest capacity of 66 Ah and RC of 140 minutes, but it also features an MCA rating of 1000 Amps and it weighs only 54 pounds.

NorthStar NSB-AGM27 battery is one of the heaviest group 27 batteries (68 pounds) and it features a somewhat smaller capacity (92 Ah) and RC rating (195 minutes) than true deep cycle group 27 batteries, but it also features an MCA rating of 1080 Amps.

Both Optima D27M and NorthStar NSB-AGM27 are very popular dual-purpose batteries that cycle well but are also able to crank surprisingly large gas and diesel engines.

Lithium Group 24 and Group 27 Batteries

Lithium group 24 and group 27 batteries are not as common as AGM lead-acid batteries, but they support a much larger number of charging/discharging cycles and they are much lighter.

On the other hand, lithium batteries initially cost more and must be recharged using either dedicated lithium battery chargers or using smart AGM battery chargers that feature dedicated lithium battery charging modes.

An important feature of the lithium group 24/27 batteries are their built-in Battery Management Systems (MBS) that monitor the batteries' operation and protect the battery from unwanted events like overcharge, over-discharge, short circuit, overheating, low temperature, etc.

If You are looking for a lightweight battery that cycles well and lasts for a very long time, and you don't mind paying some extra money, consider lithium deep cycle group 24/27 battery.

Long Story Short: If your battery compartment can accept group 27 battery, and if your charging system can properly charge such battery, and you don't mind having a somewhat heavier battery, group 27 batteries have a larger capacity, longer RC, and generally support stronger discharge currents.

Before ordering a new group 24 or group 27 battery, be sure that it is the right battery for your intended application and that it matches your needs regarding size, terminal types and orientation, capacity, CCA/MCA rating, RC rating, and similar.

And whatever You do, stay safe - these batteries are smaller than the group 31 or similar batteries, but they store plenty of energy and can release it instantly ...