Group 31 batteries are heavy-duty, commercial-grade power sources standardized at ~13×6.75×9.5 inches (LxWxH). Designed for high-capacity storage (75–125Ah), they’re used in RVs, marine systems, solar arrays, and industrial equipment. Available in lead-acid (AGM/flooded) and lithium-ion variants, Group 31 prioritizes deep-cycle resilience with 800–4,000+ cycles (lithium) and 500–1,200 cycles (AGM). Terminal types include SAE posts, studs, or dual configurations for 12V/24V setups.
What Is the Best Lithium Battery for RV Use?
What defines Group 31 battery dimensions and specifications?
Group 31 follows BCI size code 31 with ±0.25” tolerance. Key specs include 13” length, 9.5” height, and 130–180 lb weight (lead-acid). Lithium variants cut weight by 60% (e.g., 50–70 lbs). Capacity ranges from 75Ah (AGM) to 125Ah (LiFePO4), delivering 900–1,500 CCA (cold cranking amps) for diesel engines. Pro Tip: Measure battery trays before purchase—oversized cells risk vibration damage.
Beyond physical specs, Group 31’s terminal design matters. Most use SAE posts (0.75” top diameter) or 3/8”-16 studs for marine applications. Dual terminals (posts + side studs) simplify 12V/24V conversions. For example, a LiFePO4 Group 31 with 100Ah can power a 2,000W RV inverter for 1–2 hours. Pro Tip: Pair lithium batteries with temperature-compensated chargers—AGM units overcharge at ≥122°F. But why does terminal type matter? Marine environments require corrosion-resistant studs, while SAE posts suit automotive clamps.
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 |
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Weize YTX20L-BS High Performance  |
High-performance sealed AGM battery suitable for motorcycles and snowmobiles. | View on Amazon |
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Mighty Max Battery ML-U1-CCAHR  |
Rechargeable SLA AGM battery with 320 CCA, ideal for various powersport applications. | View on Amazon |
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Battanux 12N9-BS Motorcycle Battery  |
Sealed SLA/AGM battery for ATVs and motorcycles, maintenance-free with advanced technology. | View on Amazon |
| Terminal Type | Use Case | Max Current |
|---|---|---|
| SAE Posts | RV/Truck | 300A |
| 3/8” Studs | Marine | 500A |
| Dual Terminals | Solar/Industrial | 600A |
How does Group 31 compare to Group 24 or 27 batteries?
Group 31 offers 20–40% more capacity than Group 24/27. While Group 24 averages 70–85Ah, Group 31 hits 100–125Ah. Size differences: Group 24 is 10.25×6.8×8.9” vs Group 31’s larger footprint. Pro Tip: Upgrade to Group 31 if your system draws ≥100A continuous—smaller groups overheat under heavy loads.
Practically speaking, Group 31’s volume-to-power ratio justifies its use in energy-hungry systems. A Group 27 AGM battery weighs ~60 lbs with 90Ah, while Group 31 lithium delivers 125Ah at 55 lbs. For solar arrays, this means 25% more daily cycles. But what if space is limited? Group 27 may suffice for 1,000W systems, but 2,000W+ setups need Group 31’s reserve. Example: Two Group 31 LiFePO4 batteries (25.6V/200Ah) can store 5.12kWh for off-grid cabins.
What applications benefit most from Group 31 batteries?
Group 31 excels in high-demand scenarios: marine trolling motors (24V/36V), RV house banks, and telecom backup. AGM variants handle vibration in heavy trucks, while lithium models dominate solar storage. Pro Tip: Use marine-grade Group 31 with corrosion-resistant casings for saltwater environments.
Beyond typical uses, Group 31’s deep-cycle durability makes it ideal for off-grid refrigeration and medical equipment. A 100Ah lithium version can run a 12V/5A fridge for 20 hours vs 12 hours for Group 27. Example: Hospitals use Group 31 AGM banks for MRI machine backups due to 10-year lifespans. Transitionally, lithium’s 80% depth of discharge (vs AGM’s 50%) doubles usable capacity. But why not use multiple smaller batteries? Parallel setups increase failure points—Group 31 consolidates storage efficiently.
| Application | AGM | Lithium |
|---|---|---|
| Marine House Bank | 3–5 years | 8–12 years |
| RV Solar Storage | 500 cycles | 3,500 cycles |
| Industrial Backup | 1,200 cycles | 5,000 cycles |
How to Safely Ship a 100Ah Lithium-Ion Battery
Battery Expert Insight
FAQs
Only AGM/spiral-cell designs allow sideways mounting. Lithium prismatic cells risk electrolyte leakage if tilted—follow OEM orientation guidelines.
Is a Group 31 suitable for car audio systems?
Yes, especially for 3,000W+ amps. Use lithium for weight savings (50 lbs vs 130 lbs AGM) and stable voltage during bass drops.