A Group 24 marine battery measures about 10.25 inches long by 6.81 inches wide by 8.88 inches high, but overall height with terminals can reach 9.38 inches — always check clearance above the terminals before buying.
Group 24 marine battery dimensions are standardized by the Battery Council International, but whether the listing gives case height or total height with terminals makes all the difference for a clean install. Here’s exactly what the numbers mean, why they vary between brands, and how to confirm a battery will fit before you order.
What Are the Standard Group 24 Battery Dimensions?
The BCI standard for Group 24 specifies a case length of 10.25 inches (260 mm), a width of 6.8125 inches (173 mm), and a case height of 8.875 inches (225 mm). With terminals, overall height typically reaches about 9.375 inches (238 mm). BCI allows roughly ±3 mm tolerance, so minor variation between manufacturers is normal.
In practice, you’ll see several dimension sets on product pages. These differences come from case geometry, rounding conventions, and whether terminal height is included; none mean the battery is a different group size.
| Dimension Source | Length | Width | Height |
|---|---|---|---|
| BCI standard (case only) | 10.25 in (260 mm) | 6.81 in (173 mm) | 8.88 in (225 mm) |
| BCI standard (with terminals) | 10.25 in (260 mm) | 6.81 in (173 mm) | 9.38 in (238 mm) |
| Canadian Tire MOTOMASTER | 10.75 in (273 mm) | 6.75 in (172 mm) | 9.38 in (239 mm) |
| Common published variant | 10.5 in | 6.19 in | 8.88 in |
What Does “Group 24” Actually Mean?
Group size is purely a fitment standard defining outer dimensions and terminal placement — it says nothing about what’s inside. A Group 24 battery can be flooded lead-acid, AGM, gel, or lithium. Each chemistry requires a different charging profile, offers different cycle life, and carries different weight. Flooded batteries need ventilation and water checks. AGM models are sealed and handle vibration better. Lithium versions are lighter, last longer, and need a compatible BMS and charger. Typical Group 24 marine batteries deliver 70–85 amp-hours and 550–850 cold cranking amps, weighing 40–60 pounds depending on chemistry. They’re common in boats, RVs, trolling motors, golf carts, and off-grid solar systems. The group number alone won’t tell you if the battery is for starting, deep-cycle, or dual-purpose use — check the product specs.
How to Get the Right Fit
Measure the internal dimensions of your battery tray — don’t rely solely on the old battery’s label. Pay close attention to height above the terminals: that’s the most common fitment surprise. Terminal type is the second detail that trips people up. Group 24 batteries come with SAE automotive posts, stud terminals, marine twin-threaded posts, or dual terminal configurations. A battery that fits the tray may be unusable if its terminal style doesn’t match your connectors. Once physical fit is confirmed, match chemistry to your charging system. Flooded batteries need a standard lead-acid profile and occasional maintenance. AGM needs AGM voltage settings. Lithium demands a lithium charger and compatible BMS. For current comparisons across chemistries, our tested roundup of the best 24 group marine batteries covers top picks.
For a broader reference, the BatteryTender blog on marine battery group sizes explains differences between Group 24, 27, 31, and larger formats. Group 27 runs about 12.06 inches long — nearly two inches longer than Group 24 — while width and height stay similar, so it won’t fit a Group 24 tray. Always verify the group size of your old battery and the replacement’s dimensions before purchasing.
FAQs
Is Group 24 the same as a standard car battery group size?
No. Most passenger cars use Group 34, 35, or 48. Group 24 is a common marine and RV size with different dimensions, and marine batteries have thicker plates for vibration and deep discharge cycles.
Can I replace a Group 24 lead-acid battery with a lithium one of the same group size?
Often yes, but verify exact dimensions — some lithium Group 24 models use different case shapes and may be slightly smaller or larger. You’ll also need a lithium-compatible charger and BMS.
Does a higher CCA rating mean a better Group 24 battery?
Not for every use case. Higher CCA helps cold-weather starting, but for deep-cycle applications like trolling motors, amp-hour capacity is more important. Choose based on your primary use case.
References & Sources
- BatteryTender. “Marine Battery Group Sizes Explained: 24, 27, 31, 4D, 8D.” Standard BCI dimensions and fitment guidance for common marine battery group sizes.