Everything about Group 31 Battery, Dimension, Types, Features

Group 31 Battery Dimension

Are you in need of a powerful and reliable battery for your vehicle? Look no further than Group 31 batteries. In this article, we will dive into everything you need to know about Group 31 batteries including the different types, dimensions, and standout features. So let's not waste any more time and get started!

What is the Dimension of Group 31 Battery

When it comes to dimensions, Group 31 batteries are known for their standardized size made by BCI (Battery Council International). These batteries typically measure around 13 inches in length, 6.75 inches in width, and 9.5 inches in height. It is crucial to ensure that the Group 31 battery you choose fits perfectly in your vehicle's battery compartment. The format below is the sizes of other batteries.

BCI battery size

Importance of Group 31 Battery Dimensions

Understanding the dimensions of a Group 31 battery is vital for several reasons:

  1. Proper Fit: It is crucial to ensure that the battery's dimensions match the available space in the application. A secure fit prevents movement that can harm the battery or loosen electrical connections.
  2. Stability: A properly fitted battery is necessary for maintaining stability. Vibrations and jostling can damage internal components and reduce the battery's lifespan. Correct dimensions enable secure mounting, minimizing the risk of damage.
  3. Electrical Connections: Battery dimensions also affect the positioning and compatibility of electrical terminals with existing connections. Aligning the terminals correctly with the application's electrical system is essential for optimal performance and efficient energy transfer.

Applications of Group 31 Battery

Group 31 batteries have a wide range of applications due to their durability and power. Some of the most common applications include:

Trucks: Group 31 batteries are commonly used in large commercial trucks, including semis, delivery trucks, and construction vehicles. These batteries provide the necessary power to start the engine and run various electrical components.

RVs and Motorhomes: Group 31 batteries are popular in RVs and motorhomes because they can power the vehicle's engine, as well as the onboard appliances, such as lights, refrigerators, and air conditioning units.

Boats and Marine Vehicles: Group 31 batteries are ideal for powering marine vehicles, including powerboats, sailboats, and yachts. These batteries are designed to withstand the harsh marine environment and provide reliable power for starting the engine and operating navigation equipment, radios, and other electrical systems.

Off-Road Vehicles: Group 31 batteries are often used in off-road vehicles, including ATVs, UTVs, and dirt bikes. These batteries can handle the demands of off-road adventures and provide the necessary power for starting the engine and running auxiliary equipment, such as winches and lights.

Agricultural Equipment: Group 31 batteries are commonly employed in agricultural equipment, including tractors, harvesters, and irrigation systems. These batteries provide reliable power for starting heavy machinery and operating various electrical components.

Renewable Energy Systems: Group 31 batteries are also used in renewable energy systems, such as solar power or wind power installations. They can store excess energy generated by these systems efficiently and discharge it as needed.

Types of Group 31 Battery Based on the Chemistry

Group 31 batteries come in various types, including lead-acid (AGM, flooded cells, and gel cells) and Lithium Iron Phosphate (LiFePO4) batteries.

Lithium Group 31 Batteries

The popularity of lithium Group 31 batteries has been on the rise due to advancements in chemistry and electronics. Lithium batteries, particularly LiFePO4 batteries with protective Battery Management Systems (BMS), are capable of monitoring battery conditions and preventing undesirable events. These lithium batteries can often serve as direct replacements for lead-acid batteries in marine, automotive, off-the-grid, and other deep cycle applications. High-quality LiFePO4 lithium batteries like Timeusb, the lifespan can be up to 10 years with life cycle 4000-15000.

lifespan of lithium group 31 battery

Compared to lead-acid batteries, lithium batteries have several advantages. They are 2-3 times lighter, can withstand 5-10 times more charging/discharging cycles, and provide almost fade-free power regardless of the charge condition. However, they are also more expensive than their lead-acid counterparts.

It's important to note that lithium batteries require specialized chargers designed for lithium batteries or advanced AGM battery chargers with dedicated lithium battery charging modes. Learn more about How to Charge LiFePO4 Battery?

Lithium Group 31 batteries are commonly used in applications where weight savings are crucial and where their features justify the higher price. Some common applications include RV house batteries, lightweight trolling motor batteries, off-the-grid systems, and medical and security applications.

Group 31 AGM Batteries

Group 31 AGM batteries, also known as Absorbent Glass Mat batteries, are a type of sealed lead-acid (SLA) battery. These batteries have a special design where the electrolyte, which is a diluted sulfuric acid, is absorbed in a glass mat between lead plates. The average lifespan of this battery is about 6 years.

One of the main advantages of Group 31 AGM batteries is that they are maintenance-free and spill-proof. They can be mounted in any position, except upside-down. These batteries are known for their robustness and are highly resistant to vibrations and mechanical impacts.

Group 31 AGM batteries are offered as dual-purpose and deep-cycle batteries. Despite being heavier compared to lithium batteries, they are still extremely popular in a wide range of applications. The large plate size and low internal resistance enable them to provide strong currents, making them suitable as starting batteries in addition to their deep-cycle capabilities.

These batteries do not have a built-in Battery Management System (BMS) like lithium batteries. As a result, they are commonly used in mission-critical applications where a reliable power source is required, even in the face of power surges and spikes that could potentially shut off lithium batteries.

While the price of some Group 31 lithium batteries has become more affordable due to advancements in technology, AGM Group 31 batteries remain a popular choice for many applications.

Group 31 Gel Battery

Group 31 Gel Batteries, also known as Gel-Cell Lead-Acid batteries, are similar to AGM batteries in that they are maintenance-free and spill-proof. These batteries have an electrolyte that is suspended in silica gel between the lead plates. They can be mounted in any position except upside-down. Like AGM battery, the average lifespan of this battery is about 6 years.

The key difference between AGM and Gel-cell batteries lies in their discharge characteristics and self-discharge rates. AGM batteries generally have better discharge characteristics, while Gel-cell batteries tend to have lower self-discharge rates and can support a larger number of charging/discharging cycles. However, it is important to note that these characteristics can vary depending on the specific model of the battery.

Group 31 Wet/Flooded Batteries

Group 31 wet/flooded batteries, as the name suggests, consist of a liquid electrolyte that fills the space between the lead plates. Unlike AGM batteries, they are not spill-proof and require regular maintenance.

Users need to periodically check the electrolyte level and add distilled water as needed.

Due to their maintenance requirements, group 31 wet/flooded batteries are commonly used in fixed installations where routine maintenance is easily performed. Good air ventilation is also necessary to prevent the accumulation of hydrogen gas.

Types of Group 31 Battery Based on the Purpose

Group 31 batteries come in three main variants: deep cycle, starting, and dual-purpose batteries.

Group 31 Starting Batteries

Group 31 starting batteries, also known as SLI (Starting, Lighting, and Ignition) batteries, are designed to provide short bursts of high power to start engines. These batteries have thinner lead plates and are optimized for delivering quick bursts of energy. Starting batteries are commonly used in vehicles, boats, and other engine-powered equipment.

However, there are rare purely starting Group 31 batteries in the market. Most labeled as "starting" batteries, are designed to serve a dual purpose with slightly emphasized starting characteristics. These batteries are capable of delivering a minimum of 1000 CCA (Cold Cranking Amps) and 1200 MCA (Marine Cranking Amps).

CCA is the measure of the maximum current that a new, fully charged, 12V battery can deliver for 30 seconds, without the voltage dropping below 7.2V, at a temperature of 0°F (-18°C). On the other hand, MCA represents the maximum current that a new, fully charged, 12V battery can deliver for 30 seconds, without the voltage dropping below 7.2V, at a temperature of 32°F (0°C). It's important to note that some manufacturers may erroneously label their batteries with CCA values at temperatures other than 0°F, which is misleading.

To summarize, Group 31 starting batteries are versatile batteries that excel in providing starting power, and they should have a minimum CCA of 1000 and MCA of 1200.

Group 31 Deep Cycle Batteries

Group 31 deep cycle batteries are designed to provide a steady and consistent power output over an extended period. They are built with thicker plates, enabling them to withstand repeated deep discharge and recharge cycles. Deep cycle batteries are commonly used in applications that require a reliable and consistent source of power, such as marine vessels, RVs, golf carts, solar power systems, and electric vehicles.

All of Timeusb LiFePO4 lithium batteries are deep cycle. Please don’t use them as starting battery, or it would damage them.

Learn more about deep cycle vs starting battery

Group 31 Dual-Purpose Batteries 

Group 31 batteries are a type of lead-acid battery that serves a dual purpose. These batteries are designed to provide strong starting currents while also offering decent deep discharge and deep cycle capabilities. They fall between true starting batteries, which prioritize starting power, and true deep cycle batteries, which prioritize long-lasting power delivery.

For a high-quality dual-purpose Group 31 lead-acid battery, it is recommended to look for certain specifications. This includes a minimum of 900 Cold Cranking Amps (CCA), which measures the maximum current a fully charged 12V battery can deliver for 30 seconds without the voltage dropping below 7.2V at 0°F. Additionally, a battery with a minimum of 200 minutes of Reserve Capacity (RC) is desirable. RC measures the number of minutes a fully charged battery can maintain a usable voltage while supplying a constant current before dropping below 10.5V. Lastly, a battery with a minimum capacity of 100 Amp-hours (Ah) is recommended, which indicates the energy storage capacity of the battery.

Deep Cycle Lithium Group 31 Battery Recommend

The Timeusb 12.8V 100Ah Pro LiFePO4 battery is a reliable and versatile energy storage solution designed for a variety of applications. It features upgraded grade-A battery cells, a lightweight and compact design, and high energy density, making it an efficient and powerful option.

With over 4000 cycles and a lifespan of up to 10 years, this battery offers durability and longevity. Its lightweight and compact design make it easy to handle and install, while its high energy density allows for a higher usable energy output compared to traditional lead-acid batteries.

group 31 lithium battery

Equipped with a top-notch built-in BMS, this battery ensures comprehensive safety protection. It protects against overcharging, overdischarging, overcurrent, short circuit, and high-temperature environments, enhancing the battery's reliability and minimizing potential hazards.

Overall, the Timeusb 12.8V 100Ah Pro LiFePO4 battery provides superior performance and safety features, making it an excellent choice for residential, commercial, and recreational energy storage needs.

Group 31 Battery with Low Temperature Protection

The Timeusb 12V 140Ah lithium battery is a cutting-edge storage solution designed for individuals living in regions with long winters. With its low-temperature protection feature, this battery automatically cuts off charging when the cell temperature drops below 32℉, ensuring reliable performance even in extremely cold conditions.

lithium battery with low temperature protection

Boasting automotive-grade battery cells and an optimized cell structure, the 12V 140Ah lithium battery delivers exceptional performance, with a capability of up to 15,000 deep cycles and a remarkable lifespan of 10 years.

This battery offers an impressive energy output of up to 1792Wh, making it ideal for a range of applications. Expansion is also possible, with the ability to connect up to 16 lithium iron phosphate batteries using a 4P4S configuration to create a powerful 51.2V 560Ah system, capable of storing up to 28.672kWh of energy and supporting a maximum load power of 20.480kW.

In addition to its outstanding performance, the Timeusb 12V 140Ah lithium battery is remarkably lightweight, weighing just 27.9lbs. This is approximately half the weight of a comparable 12V 100Ah lead-acid battery, making it easier to handle and transport. With a high energy density of 64.23Wh/lb, this battery offers a compact and efficient power storage solution.

Overall, the Timeusb 12V 140Ah lithium battery combines advanced features, exceptional reliability, and remarkable energy density, making it the perfect choice for various applications where high performance, durability, and lightweight design are essential.


In conclusion, Group 31 batteries are an excellent choice for those seeking a powerful and dependable battery for their vehicles. With various types available, including flooded lead-acid, AGM, and gel batteries, you can select the type that best suits your specific needs and preferences. Their standardized dimensions and standout features such as high reserve capacity, cold cranking amps, and maintenance-free operation make Group 31 batteries a top contender in the automotive industry. Upgrade your vehicle's battery to a Group 31 battery and experience a reliable power source that will keep you on the move.