A Group 31 deep cycle battery is a heavy-duty 12-volt battery commonly used in marine, RV, and industrial applications. Known for its robust capacity and deep discharge capabilities, this battery size is ideal for delivering long-lasting power over extended periods.
What Defines a Group 31 Battery?
Group 31 is a classification by the Battery Council International (BCI) that refers to the physical dimensions of the battery. These batteries typically measure about 13 x 6.75 x 9.44 inches (L x W x H) and weigh between 55 to 75 pounds depending on chemistry and features.
They are available in several types:
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Flooded Lead Acid
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AGM (Absorbent Glass Mat)
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Gel
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LiFePO4 Lithium
What Makes It a Deep Cycle Battery?
Unlike starting batteries designed to deliver quick bursts of power, deep cycle batteries are engineered to deliver a steady current over long periods. A Group 31 deep cycle battery can discharge up to 80% of its capacity without damage, making it ideal for applications where long runtimes are needed.
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 |
Common uses:
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Powering RV appliances
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Running trolling motors
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Off-grid solar setups
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Backup power systems
Advantages of Group 31 Deep Cycle Batteries
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High Amp-Hour Capacity: Typically ranging from 95Ah to 125Ah
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Long Lifespan: Especially for AGM or lithium variants
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Versatile Use Cases: Ideal for both stationary and mobile applications
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Durability: Resistant to vibrations and harsh environments
Maintenance and Charging Tips
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Use a smart charger designed for deep cycle batteries
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Keep the battery at 50–80% charge for longer life
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Avoid overcharging or discharging below 20%
FAQ
What is the amp hour rating of a Group 31 deep cycle battery?
Most models range between 95Ah to 125Ah, depending on the brand and chemistry.
Can I use a Group 31 battery for starting an engine?
Some dual-purpose models can be used for both starting and deep cycle, but for consistent engine cranking, a dedicated starting battery is better.
What is the typical lifespan of a Group 31 battery?
Flooded types last 2–4 years, AGM 4–7 years, and lithium batteries can last 8–10 years or more.
Conclusion
A Group 31 deep cycle battery offers high capacity, reliability, and versatility, making it a solid choice for RV, marine, and off-grid users. With proper maintenance, it can serve as a dependable power source for years to come.