By Erik Watkins

Group 31 Battery Dimensions, Sizes, Weights & Specifications

Last Updated: July 6, 2022
Group 31 Battery

You may have heard of the group 31 battery, and you want to find among these BCI Group heavy-duty batteries the suitable one for your vehicle. Having knowledge about the power supplier is important as you don’t want to make an incorrect buying option which can waste your time and money and cause damage to you.

This article will give you information about this group, such as dimensions and features, and recommend the ideal one for your situation.

What Is A Group 31 Battery?

Group 31 lithium Battery

Group 31 battery belongs to the coding system for battery sizes. Battery Council International (BCI) established the system for automobiles and other lead batteries. The purpose of these standardized codes is to simplify the class of batteries.

This series, categorized as a heavy-duty one, is one of the most popular groups used for automobiles, marines, commercial truck applications, and other similar vehicles that require reliable and durable power to start. 

Group 31 Batteries Comparison Chart

All the batteries have slightly different specs but meet the requirement to start the engines and supply reserve power. Here are some models for your reference.

ModelBattery ChemistryCapacity (Ah)RC (min)CCAMCAWeight (lbs/kg)
Aicipow PDAC-12100Deep CycleLiFePO4100~240100A cont.26 lbs; 11.8 kg-
AIMS Power LFP12V100BDeep CycleLiFePO4100~240100A cont.200A 10s28.5 lbs; 12.9 kg-
Ampere Time 12V 100AhDeep CycleLiFePO4100~240280A 5s24.25 lbs; ~11 kg
Banshee LFP-31MDual PurposeLiFePO4100~2401200 CCA24.2 lbs; 11 kg-
Bioenno Power BLF-12100WSDeep CycleLiFePO4100~240100A cont.200A 5s28.1 lbs; 12.8 kg-
Chins 12V100AhDeep CycleLiFePO4100~240100A cont.300A 5s.23.9 lbs; 10.8 kg-
Eco-Worthy 12V150AhDeep CycleLiFePO4 150~360150A cont.36.7 lbs; 16.6 kg-
Exide XMC-31Deep CycleAGM100200925111068 lbs; 31 kg
Flypower 12V 100AhDeep CycleLiFePO4100~240100 cont.200A surge 3-5s24.3 lbs; ~11 kg
JITA 12V100AhDeep CycleLiFePO4100~240100A cont.23.8 lbs; 10.8 kg-
Lifeline GPL-31TDeep CycleAGM10519560075069 lbs;  31.5 kg-
Lifeline GPL-31XTDeep CycleAGM12523065080069 lbs; 31.5 kg-
Lifeline GPL-3100TDual PurposeAGM10022881095067 lbs; 30.4 kg-
NorthStar ELT-AGM31Dual PurposeAGM100190925105065.7 lbs; 29.8 kg-
NorthStar NSB-AGM31Dual PurposeAGM1032201150137075 lbs; 34.0 kg-
NorthStar NSB-AGM31MDual PurposeAGM1032201150137075 lbs; 34.0 kg –
Odyssey 31-PC2150SDual PurposeAGM1002051150137077.8 lbs; 35.3 kg 
Optima 8052-161 D31MDual PurposeAGM75155900112559.8 lbs; 27.1 kg
PacPow 12V 100AhDeep CycleLiFePO4100~240100A cont.300A 10s27.56 lbs; 12.5 kg
Power Queen 12V100AhDeep CycleLiFePO4100~240100A cont.25.25 lbs; 11.0 kg-
Vatrer 12V 100AhDeep CycleLiFePO4100240100A cont.33 lbs; 15 kg
Vmaxtanks XTR31-135Deep CycleAGM13526573092077 lbs; 34.9 kg-
Weize FPLI-12100AHDeep CycleLiFePO4100~24050A cont.100A 3s26.4 lbs; 12.0 kg-
Wingda W100-12V100AHDeep CycleLiFePO4100~24050A cont.23.8 lbs; 10.8 kg-
Zooms 12V 100AhDeep CycleLiFePO4100~240100A cont.25.35 lbs; ~11.5 kg

Group 31 Battery Chemistry, Dimensions (Sizes), Weight, And Specs 

The dimension of the group type is around 13 x 6.8 x 9.44 inches or 330 x 173 x 240 mm. The weight varies depending on the chemical inside. For example, lithium batteries weigh 30 pounds, while lead-acid batteries weigh 80 pounds. From the dimension, you can somehow conclude its power generation.

The BCI group 31 comprises batteries – 12V (lead-acid) and 12.8V (lithium). Sometimes, you can find group 31 lithium batteries with 24 volts and 36 volts as well. The 12V Duracell ultra is suitable for commercial equipment. 

According to the BCI size classification, no specific ampere rating is given to the group. However, it’s often seen between 95 to 125-amp hour capacity. Lithium iron phosphate batteries and lead-acid batteries such as flooded cells, gel cells, and AGM are most commonly used.

Lithium Batteries

LiFePO4 battery (Lithium Iron Phosphate), possessing Battery Management Systems (BMS), is an example of the advanced chemistry and electronics combination. 

The system can control different aspects of battery use, such as voltage, temperature, and input/output current, and protect it from unwanted damages. The type is increasingly popular and can be used instead of the lead-acid type in many deep cycle uses.

Compared to lead-acid batteries, the type overwhelms in many specs. It’s 2-3 times lighter, can tolerate charging cycles 5-10 times more, and gives almost the same power no matter the charging condition.

Due to its advantages, its price is more expensive. Plus, you need dedicated advanced AGM chargers or lithium chargers that support dedicated lithium charging mode.

Lithium type is used for lightweight trolling motor, RV house, security, and medical applications, which prefer weight savings and manipulate all its advantages.

Deep Cycle Batteries

It performs well when discharging at a low current, although it can’t produce a strong current. Some of the best in this category can work 20 hours in 120-125 amps hours of capacity with an RC rating of 240-250+ range.

Off-grid, marine applications or electric vehicles with the highest requirements for deep discharge and cycle features are a big market for this category.

Starting Batteries

Pure starting batteries are rare in the market. Those you see that are labeled “cranking” or “starting” are actually made for dual purposes. The actual product may vary, and the actual temperature is not the same.

For example, the CCA (Cold Cranking Amps) value should be measured at 0°F, and a true “starting” should deliver a minimum of 1000 CCA. However, some manufacturers describe that their products have 1000 CCA at 32 degrees F or 68 degrees F, or even 80 degrees F.

Dual-purpose Batteries

Mostly lead-acid types with extra reserve capacity belong to this dual-purpose category. As its name suggests, it’s made with the remarkable features of two types: starting and deep cycle. 

Its starting current is worse than the starting one but better than the deep cycle, and its deep cycle and deep charge features are worse than the original one but better than the starting type.

The ideal power of this type is to supply 900 CCA, 100 Ah, and 200 minutes reserve capacity at minimum. Still, there remain some exceptions to this group. For example, Optima D31M is designed lighter, thus weaker than some siblings in the same category.

Best Group 31 Batteries And Recommendations

There are some candidates that we can think of as the best group 31 batteries, but it’s still difficult to come to a conclusion. Each type has different features, and their small details, such as the depth and number of recommended discharge and charge cycles, numbers, and types of terminals, are also not the same. 

Plus, some more criteria are needed to consider, such as price, warranty, etc. The most important thing is your requirements and preferences. Below is the list of best products of BCI group 31 heavy duty battery that might be the correct ones that you are looking for. 

Best Lightweight Dual-Purpose AGM Group 31 Battery

If you prefer a multipurpose and lightweight SLA or battery pack, there are some suggestions for you. They are Optima D31M BlueTop, Optima D31T YellowTop, and Optima D31A YellowTop.

Optima D31M BlueTop
Optima D31M BlueTop

They are only 60 pounds and can supply 900 CCA and 1125 MCA despite the 75Ah nominal capacity. Many users said it would be good if the manufacturer tried improving its 155-minute RC. Nevertheless, in general, it’s a reliable dual-purpose battery that is slightly forward of the starting type.

Best Deep Cycle AGM Group 31 Battery

Vmaxtanks SLR125
Vmaxtanks SLR125

Vmaxtanks SLR125 should be the one that deserves our vote. Since it’s specialized for deep charge and deep cycle performance, you shouldn’t use it as a dual purpose or a starting battery. It’s perfect for off-the-grid uses.

With a weight of about 75lbs (34kg), the power deliverer is one of the heaviest in the category. Its features are amazing, with a 260-minute RC rating and a 20-hour capacity of 125 amps.

Best AGM Group 31 Battery

AGM (Absorbed Glass Mat), well known for its starting power, RC, and long battery life, is used in many heavy-duty applications such as heavy-duty trucks.

Odyssey 31M-PC2150

The winner in this category is Odyssey 31M-PC2150. There are several versions of it that are different in number, type, and battery terminals, battery posts but the internal parts are the same.

Some of the most highlighted versions are Odyssey 31M-PC2150ST-M Trolling Thunder Marine Dual Purpose Battery, Odyssey 31-PC2150S Heavy Duty Commercial Battery, and Odyssey 31-PC2150T Heavy Duty Commercial Battery. 

Why Odyssey 31M-PC2150 And Not NorthStar

NorthStar NSB-AGM31 and NorthStar NSB-AGM31M (marine version) are well-performed automotive batteries; we still give the best title to Odyssey 31M-PC2150 for some reasons.

They both have equal pulse current of 2150 amps and provide the same 1370 MCA and 1150 CCA. 

From the outlook, NorthStar NSB-AGM31 may have advantages. It can deliver 103 amps per hour for 20 hours before dropping to 10.5 volts, equaling 1.75 volts each cell. The Odyssey 31M-PC2150 can supply 100 Ah for 20 hours before reaching 10.05 volts equivalent to 1.675 volts for each cell. The NorthStar can withstand 900 cycles down to 50% discharge, while this number in Odyssey is 650. 

However, the Odyssey performs greatly at extremely cold temperatures. It can function from -40 degrees Celsius (-40 degrees Fahrenheit) to 80 degrees Celsius (176 degrees Fahrenheit). The self-discharge rate is low – one more remarkable plus of the brand. 

It’s tough to compare and select between the two duracell ultra BCI group products. NorthStar works well with regular cycle applications. If you want to have the top product and don’t need it to operate in cold weather, stretch your budget more for the NorthStar. 

Meanwhile, the Odyssey is vibration resistant and reliable in cold performance. Go for it if you need a durable, strong component for rugged applications.

Lead-Acid vs. Lithium Group 31 Batteries

Technology development helps reduce the price gap between lithium and lead-acid batteries. In turn, it makes the options between products more difficult to choose. 

If you usually need to start the medium to the large engine and are looking for a dual-purpose type, then the AGM group 31 batteries are for you. 

Lithium group 31 batteries are an ideal choice where lightweight is preferred. Many products of this category also can tolerate a huge number of discharging and charging cycles but produce no extra high current. 

Some critical applications require reliable batteries that can supply energy even when the power fails to perform. In this case, the AGM battery is better than the lithium one. The Battery Management Systems (BMS) can disconnect the lithium type due to extremely high flow. 

Conclusion

The last thing to remember is no matter what type you choose for your passenger vehicles, safety is the most important. Group 31 battery has strong circuits and can put you at risk. Ask for help from nearby stores if you aren’t confident in dealing with choosing the correct battery, pickup in-store, and other issues.

Group 31 Battery Testing

Automotive Master Mechanic at PowerAll

With 7 years experience in management positions leading automotive mechanics at PowerAll, Erik Watkins wishes to share useful knowledge and information about automotive mechanical equipment.

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