Group 24 and Group 31 batteries differ primarily in size, capacity, and application. Group 31 batteries are larger (13×6.8×9.4 inches) with higher reserve capacity (180-220 minutes) for heavy-duty use, while Group 24 batteries (10.3×6.8×8.9 inches) offer 120-140 minutes for moderate needs. Voltage remains identical (12V), but Group 31 handles deeper discharges better in deep-cycle applications.
What Is a Group Size 24 Battery?
How Do Physical Dimensions Compare Between Group 24 and Group 31 Batteries?
Group 24 batteries measure 10.3″ L x 6.8″ W x 8.9″ H, weighing 40-50 lbs. Group 31 models are larger at 13″ L x 6.8″ W x 9.4″ H, weighing 55-70 lbs. The extra size allows Group 31 to house thicker lead plates, increasing durability and charge capacity. Terminal placement follows BCI standards, but Group 31’s larger case may require modified battery trays in some vehicles.
What Capacity Differences Exist Between These Battery Groups?
Group 31 batteries provide 20-35% more capacity than Group 24. Typical ratings: Group 24 offers 70-85 Ah (Amp Hours), Group 31 delivers 95-125 Ah. Reserve capacity diverges significantly – Group 24 lasts 120-140 minutes at 25A draw, while Group 31 sustains 180-220 minutes. Cold Cranking Amps (CCA) differ similarly: 650-800 CCA vs. 900-1150 CCA respectively, making Group 31 better for cold climates.
Top 5 best-selling Group 14 batteries under $100
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Weize YTX14 BS ATV Battery  |
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| Specification | Group 24 | Group 31 |
|---|---|---|
| Typical Ah Capacity | 70-85 | 95-125 |
| Reserve Capacity (minutes) | 120-140 | 180-220 |
| CCA Range | 650-800 | 900-1150 |
These capacity differences become particularly noticeable in real-world applications. For marine enthusiasts running multiple electronics simultaneously, the Group 31’s extra reserve capacity can mean the difference between returning to port under power versus needing a tow. Off-grid solar installations benefit significantly from Group 31’s ability to store surplus energy during cloudy days, with its 125Ah models providing 40% more usable energy than comparable Group 24 units when considering recommended depth-of-discharge limits.
How Does Temperature Affect These Battery Groups Differently?
Group 31’s larger electrolyte volume provides better thermal mass, maintaining functionality from -40°F to 140°F vs. Group 24’s -20°F to 120°F range. In freezing conditions, Group 31 loses 15% less capacity. High-heat environments (engine compartments) reduce Group 24 lifespan by 30% compared to Group 31’s 20% degradation. Both benefit from insulation, but Group 31 tolerates wider thermal swings.
| Temperature Condition | Group 24 Capacity Loss | Group 31 Capacity Loss |
|---|---|---|
| -20°F (-29°C) | 45% | 30% |
| 32°F (0°C) | 15% | 10% |
| 100°F (38°C) | 25% | 18% |
The thermal advantages of Group 31 batteries make them particularly suitable for extreme environments. In desert climates where under-hood temperatures regularly exceed 130°F, Group 31’s superior heat resistance can extend service life by 18-24 months compared to Group 24 models. For cold storage facilities maintaining -10°F environments, Group 31 batteries demonstrate 40% better cold-start performance while maintaining stable voltage output during extended low-temperature operation.
“The trend toward accessory-heavy vehicles is pushing consumers to Group 31 batteries earlier. While 70% of passenger vehicles still use Group 24, we’re seeing 20% annual growth in Group 31 sales for aftermarket upgrades. The key is matching plate thickness to discharge patterns – we recommend Group 31 for anyone drawing over 50Ah daily.”
John Carlisle, Power Systems Engineer at BatteryTech Solutions
FAQ: Common Questions Answered
- Can I replace a Group 24 with Group 31 battery?
- Only if your vehicle’s battery tray accommodates 13″ length and 9.4″ height. Check clearance around terminals and securement brackets.
- Do both groups use identical terminal types?
- Yes – both typically feature SAE posts. Some marine variants may include dual terminals (SAE + stud).
- How often should I test these batteries?
- Monthly voltage checks for stationary applications. Load test every 6 months – Group 31 tolerates more frequent deep cycling.
- Which handles vibration better?
- Group 31’s thicker plates and case design provide 30% better vibration resistance per MIL-STD-810 tests.