A Group 31 battery typically measures 13 inches long, 6.8 inches wide, and 9.4 inches tall (33 x 17.3 x 24 cm). This standardized size ensures compatibility with automotive, marine, and solar systems requiring high capacity. Weight ranges from 55-75 lbs depending on chemistry. Terminal positions and case design follow BCI Group 31 specifications for universal fitment.
What Is a Group Size 24 Battery?
How Do Group 31 Battery Dimensions Compare to Other Battery Groups?
Group 31 batteries are larger than Group 24 (10.25″ L) and Group 27 (12.4″ L) but smaller than 8D commercial batteries. Their rectangular footprint maximizes capacity while fitting common battery trays. Unlike cylindrical L16 solar batteries, Group 31’s block shape prevents rolling in marine applications. Height variations exist between flooded (taller) and AGM (shorter) models due to internal construction differences.
What Applications Require Group 31 Battery Dimensions?
The Group 31 form factor dominates in:
1. Heavy-duty trucks (cold cranking amps)
2. Marine trolling motors (deep-cycle endurance)
3. Off-grid solar systems (amp-hour capacity)
4. RV house batteries (vibration resistance)
5. Industrial equipment (reliable starting power)
Its size accommodates thick lead plates for high performance while maintaining installability in confined engine compartments or battery boxes.
Top 5 best-selling Group 14 batteries under $100
| Product Name | Short Description | Amazon URL |
|---|---|---|
|
Weize YTX14 BS ATV Battery  |
Maintenance-free sealed AGM battery, compatible with various motorcycles and powersports vehicles. | View on Amazon |
|
UPLUS ATV Battery YTX14AH-BS  |
Sealed AGM battery designed for ATVs, UTVs, and motorcycles, offering reliable performance. | View on Amazon |
|
Weize YTX20L-BS High Performance  |
High-performance sealed AGM battery suitable for motorcycles and snowmobiles. | View on Amazon |
|
Mighty Max Battery ML-U1-CCAHR  |
Rechargeable SLA AGM battery with 320 CCA, ideal for various powersport applications. | View on Amazon |
|
Battanux 12N9-BS Motorcycle Battery  |
Sealed SLA/AGM battery for ATVs and motorcycles, maintenance-free with advanced technology. | View on Amazon |
Commercial fishing vessels frequently utilize Group 31 batteries for dual starting and winch operations due to their balanced size-to-power ratio. In renewable energy installations, the standardized dimensions allow easy integration with existing rack systems. Trucking companies prefer these batteries for their ability to deliver 950-1150 CCA (Cold Cranking Amps) without requiring custom mounting solutions. The table below shows common applications and their specific requirements:
| Application | Key Requirement | Group 31 Advantage |
|---|---|---|
| Marine Trolling | Vibration resistance | Reinforced case design |
| Solar Storage | Cycle life | Thick lead plates |
| RV Systems | Space efficiency | Compact footprint |
Why Does Case Design Matter for Group 31 Battery Installation?
Group 31 batteries feature reinforced polypropylene cases with:
• Ribbed bottoms for vibration dampening
• Stackable designs for dual-battery setups
• Terminal protectors to prevent accidental shorts
• Lift handles molded into case sides
Case thickness varies between starting (thinner) and deep-cycle (thicker) versions. AGM batteries often include pressure relief valves oriented for vertical/horizontal mounting flexibility in tight spaces.
How Does Temperature Affect Group 31 Battery Performance?
Extreme temperatures impact Group 31 batteries:
• Cold reduces cranking amps by 30-50% at -18°C
• Heat accelerates plate corrosion above 27°C
• AGM handles thermal stress better than flooded
• Lithium variants maintain performance from -20°C to 60°C
Proper battery box ventilation and insulation blankets help mitigate temperature extremes while preserving the battery’s physical integrity.
Temperature fluctuations significantly affect electrolyte stability in flooded batteries, requiring more frequent water level checks in hot climates. Lithium iron phosphate (LiFePO4) batteries maintain stable voltage output across wider temperature ranges but may require built-in heating systems in sub-zero environments. The table below compares temperature tolerances:
| Battery Type | Operating Range | Capacity Loss at -10°C |
|---|---|---|
| Flooded Lead Acid | 0°C to 40°C | 40% |
| AGM | -15°C to 50°C | 25% |
| Lithium | -20°C to 60°C | <5% |
What Safety Precautions Apply to Group 31 Battery Handling?
Due to their size and weight:
1. Use lifting straps rated for 100+ lbs
2. Secure with Grade 8 mounting hardware
3. Maintain 1″ clearance from metal surfaces
4. Wear acid-resistant gloves when servicing
5. Never install damaged/swollen batteries
Case thickness determines impact resistance – deep-cycle models withstand rougher handling than starting batteries.
Expert Views
“Modern Group 31 batteries push size-to-capacity boundaries through advanced materials. Thin Plate Pure Lead (TPPL) AGM tech fits 115Ah in standard dimensions that previously held 100Ah. Lithium variants now deliver 200Ah in same footprint. Always verify actual measurements – some ‘Group 31’ lithiums are 0.5″ smaller per side but use spacer kits for compatibility.”
– Energy Storage Systems Engineer, Maritime Power Solutions
Conclusion
The physical size of Group 31 batteries (13×6.8×9.4″) makes them ideal for high-demand applications requiring substantial power reserves. While dimensions follow BCI standards, subtle variations in case design, terminal placement, and internal architecture affect real-world performance. Understanding these physical characteristics ensures proper selection, installation, and maintenance across automotive, marine, and renewable energy systems.
FAQs
- Can Group 31 batteries fit in Group 27 boxes?
- No – Group 31 is 1.6″ longer than Group 27. Modified trays or adjustable brackets are required for proper installation.
- Do lithium Group 31 batteries weigh less?
- Yes – Lithium variants average 35 lbs vs 70 lbs for lead-acid, while offering 2-3x more usable capacity.
- How often should I check Group 31 battery terminals?
- Inspect every 3 months. The large terminals (typically M8 studs) can loosen due to vibration in mobile applications.