Group 27 refers to a standardized battery size classification defined by the Battery Council International (BCI). It specifies physical dimensions, terminal placement, and capacity for deep cycle batteries, ensuring compatibility with applications like RVs, marine systems, and solar storage. These batteries typically measure 12.4 x 6.8 x 9.4 inches and offer 80-110 Ah capacity.
What Is a Group Size 24 Battery?
How Is Group 27 Defined in Battery Standards?
Group 27 batteries adhere to BCI standards, which dictate their length (12.4 inches), width (6.8 inches), and height (9.4 inches). This classification ensures uniform terminal positioning (top posts) and compatibility with designated battery trays. The group number also correlates with capacity ranges, with Group 27 typically delivering 80-110 amp-hours (Ah) in deep cycle configurations.
What Are the Key Dimensions of a Group 27 Battery?
A Group 27 deep cycle battery measures 12.4 x 6.8 x 9.4 inches (LxWxH), weighing 50-70 pounds depending on technology. These dimensions allow installation in marine engine compartments, RV battery bays, and off-grid enclosures. The standardized size prevents fitment errors, though users should verify tray clearances for ventilation and maintenance access.
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 |
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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 |
How Does Group 27 Compare to Group 24 and Group 31 Batteries?
Group 27 bridges capacity between Group 24 (70-85 Ah) and Group 31 (95-125 Ah). While Group 24 suits light loads, Group 27 handles moderate energy demands in RVs or fishing boats. Group 31 outperforms both in capacity but requires 13% more space. Group 27 offers optimal balance for users needing extended runtime without oversizing compartments.
| Battery Group | Capacity (Ah) | Dimensions (inches) |
|---|---|---|
| Group 24 | 70-85 | 10.3 x 6.8 x 8.9 |
| Group 27 | 80-110 | 12.4 x 6.8 x 9.4 |
| Group 31 | 95-125 | 13 x 6.8 x 9.4 |
What Applications Commonly Use Group 27 Deep Cycle Batteries?
Group 27 batteries power trolling motors, RV house systems, and solar storage installations. Their 100Ah average capacity supports 8-10 hours of moderate marine electronics use or 2-3 days of RV lighting/fan operation. They’re also deployed in floor scrubbers, golf carts, and backup power systems requiring cyclic discharge/recharge endurance.
What Maintenance Practices Extend Group 27 Battery Life?
Monthly voltage checks (maintaining 12.4V+), terminal cleaning with baking soda solutions, and equalizing charges every 3 months prolong lifespan. Avoid discharging below 50% depth-of-discharge (DoD). For flooded models, refill with distilled water when plates are exposed. Temperature-controlled charging below 104°F prevents thermal runaway in AGM/Gel variants.
Advanced users should implement load testing every 6 months to identify capacity fade. Use a digital hydrometer for flooded batteries to measure specific gravity (1.265-1.299 ideal). Apply anti-corrosion gel to terminals after cleaning, and ensure proper ventilation to prevent hydrogen gas buildup. Storage in cool (50-70°F), dry environments reduces self-discharge rates by up to 60% compared to garage storage.
| Maintenance Task | Frequency | Tools Required |
|---|---|---|
| Voltage Check | Monthly | Multimeter |
| Terminal Cleaning | Quarterly | Baking soda, wire brush |
| Equalization Charge | Every 3 Months | Smart charger |
How Does Group 27 Perform in Extreme Temperatures?
Group 27 AGM batteries retain 85% capacity at 14°F but suffer 30% capacity loss at -22°F. In heat above 100°F, cycle life halves for every 15°F increase. Insulating battery boxes and using temperature-compensated chargers mitigates performance drops. Flooded models are more heat-tolerant but require frequent water replenishment in arid conditions.
Lithium iron phosphate (LiFePO4) variants maintain 95% capacity from -4°F to 140°F, making them superior for extreme climates. However, charging below freezing requires built-in heating elements. Thermal imaging shows AGM batteries develop 15°F higher internal temps than flooded types during heavy discharge. Always maintain at least 1/2″ air gap around batteries in enclosed spaces for proper heat dissipation.
What Are the Costs of Group 27 Deep Cycle Batteries?
Prices range from $200 for flooded lead-acid to $600+ for lithium variants. Mid-tier AGM models average $350-$450 with 4-6 year lifespans. Lithium (LiFePO4) Group 27 batteries cost 3x more upfront but last 10+ years, offering 3,000+ cycles vs. 500-800 in lead-acid. Consider total cost-per-cycle: lithium often proves cheaper long-term.
“Group 27 remains the Swiss Army knife of deep cycling—versatile enough for most marine and RV applications. However, users often overlook plate thickness. Opt for batteries with 0.12″+ plates; they withstand deeper discharges better. Also, pairing two Group 27s in parallel often outperforms a single Group 31 in fault tolerance and weight distribution.”
— Marine Power Systems Engineer, 15+ Years Experience
- Can Group 27 Batteries Be Used as Starting Batteries?
- While possible, deep cycle Group 27 batteries prioritize sustained energy delivery over cold cranking amps (CCA). For dual-purpose use, select hybrid models labeled “marine deep cycle” with 800+ CCA ratings.
- How Long Does a Group 27 Battery Last on a Single Charge?
- Runtime depends on load: a 100Ah battery running a 10A device lasts ~10 hours at 50% DoD. With a 50A inverter load, expect ~1 hour. Always derate capacity by 20% for real-world conditions.
- Are Group 27 Batteries Universal Across Brands?
- Dimensions and terminals are standardized, but capacities and chemistries vary. Cross-reference BCI specs when swapping brands. AGM-to-flooded transitions may require charging profile adjustments.