Best Group 31 Deep Cycle Battery | Going Farther for Longer

The battery is the central part of a car or a boat that keeps other parts working, similar to a

Just like the human heart……

Our body keeps working as long as this organ is in sound health. When a battery stops working, you must go for a replacement.

But making the right choice for your need is not a piece of cake.


Amongst the numerous flashy advertisements, you will get confused about which is the best fit for your vehicle, especially if it’s in 31 group. The result? It is quite challenging to find reliable manufacturers.

So, what’s the solution?

We have come up with a list of top-rated battery reviews with beauty tips and reliable pieces of information to help you choose the best group 31 deep cycle battery.

What is the best group 31 battery?

  • Best Group 31 Deep Cycle Battery Amp Hours: Optima D31M BlueTop Starting and Deep Cycle Battery

“The finest group 31 starting battery”

  • Best 31 Series Marine Battery: Renogy Deep Cycle Group 31 AGM Battery

“A heavy-duty battery with a longer lifespan” Best Group 31 Commercial Truck Battery

What’s A Group 31 Battery?

The Group 31 battery is a commercial or industry-standard battery that needs for heavy-duty trucks in every use and vocations.

Multiple storms are often used in a similar design to contain engine cranking and truck accessories or other jobs requiring the truck’s power demand.

So, what is a group 31 marine battery?

Group 31 repeatedly submits to the total physical measurement of the battery covering. The case size can’t directly affect the AMP Hour, but some correlations can be a big case size and a higher capability.

5 Best Group 31 Deep Cycle Battery Reviews

Let’s proceed to meet the best group 31 deep cycle battery that is hitting the market.

We can assure you something…….

We will try to support you with the most reliable information about them.

1. Optima D31M BlueTop Starting and Deep Cycle Battery

Optima D31M BlueTop Starting and Deep Cycle Battery

Key Features:

  • Impressive Reserve Capacity
  • Capable to recharge quickly
  • Spiral Cell technology can eliminate acid spills


  • Voltage: 12 volts
  • Weight: 59.8 pounds
  • Capacity: 75 Ah
  • Cold Cranking Amps (CCA): 900
  • Warranty: 2-year full replacement warranty

Keeping in mind the needs of customers who own large boats for fishing, the Optima D31M is one of the best lightweight battery, suitable for dual-use starting and deep cycle.

It is an outstanding, functional battery for those who look for reliable stuff.

The exceptional Spiral Cell design of Optima D31M enables you to enjoy more control and critical tolerance. This technology made this battery completely spill-proof. Luckily, it is 15 times more efficient to resist vibration.

Yes, 15 times more efficient!

Moreover, the battery can recharge up to three times more than other conventional sales in the market. You can mount it- wherever you want.

The low self-discharge rate is also a surprising feature you must notice. It means the battery is still holding a charge after a long time of inactivity.

Sound’s impressive, isn’t it?

Finally, the Optima D31M blue top is a perfect choice for your boat or RV if you can relate with a little more price. What they say, “you can’t get golden at a silver price”. But considering everything, this optima is definitely a good shot for the bucks.


  • Low self-discharge rate
  • Highly resistant to vibration
  • Maintenance-free


  • Quite heavy

2. Renogy Deep Cycle Group 31 AGM Battery

Renogy Deep Cycle Group 31 AGM Battery

Key Features:

  • Suitable for multipurpose usage
  • Interconnecting by wires provides even more power
  • Can prevent overcharging


  • Voltage: 12 volts
  • Weight: 66 pounds
  • CCA: 1800
  • Number of cells: 6
  • Reserve Capacity: 10-hours

Renogy Agm battery draws the attention for standby use applications as well as cyclical use applications.

And that’s obviously for a good reason.

We mean, it is an excellent choice for telecommunication, security, or emergency lighting system. Again, usable for RV’s, boats, or medical equipment. Of course, it comprises high-quality features.

So, let’s see why excellent?

Most importantly, versatility is the best feature that assists Renogy to stand out from many. Indeed, people with multiple vehicles will get them more practical.

But what if I desire more power?

Well, Renogy comes with the solution that is Renogy Battery Interconnect Cables. You can now fix quite a lot of batteries in a parallel battery bank and show off the presentation. Eventually, you can power an entire reliable grid.

To sum up, when you crave more and even more power to operate your reliable grid or in your RV that comes with more electronic extra’s, turn into- Renogy Agm12- 100 battery.

A longer lifespan with high capacity, you get from Renogy. It is especially suitable for those who do a lot of dry camping.


  • No risk of spills or leaks
  • Only a few maintenances required
  • Suitable to use for backup power daily


  • Extremely large and heavyweight for this you should have proper space before buying it
  • Recharging takes more time than other batteries on our list

3. VMAX AGM Sealed Marine AGM Battery

VMAX AGM Sealed Marine AGM Battery

Key Features:

  • Ensures 8-10 years long service life
  • Low self-discharge
  • High reserve capacity


  • Capacity: 120Ah
  • Voltage: 12 volts
  • Weight: 75 pounds
  • CCA: 900
  • Reserve Capacity: 230 minutes
  • Service life: 8-10 years

Nothing but a good energy source (Battery) can make your journey safe and boost your fishing experience.

Too true!

Again, regarding the best group 31 deep cycle battery, VMAX MR-137-120 by VMAXTANKS hit the market.

So, let’s see what feature brought it into the discussion?

Firstly, VMAX MR137-120 proves that without using any type of contaminants, even avoiding traditional silica gels, it is possible to comprise an effective electrolyte suspension system.

It consists of a highly riddled absorbent glass met (AGM) that absorbs electrolytes within the battery. Sure, you get more efficiency, no bothering about leakage or corrosion. That’s why it is named-

Non-spillable, non-hazardous.

Contrary to competitors that use lead alloy plates, this battery contains lead-tin alloy plates that provide outstanding performance and 8-10 years of prolonged service life.

No matter which environment you use, it is durable.

In the end, if you have space in your boat and can withstand heavyweight, then don’t miss the premium quality features of the VMAX Agm Marine battery.

If you are still thinking reusable and rechargeable battery, we suggest you think about this unit.


  • Doesn’t require much more Maintenance
  • Can withstand a wide range of temperatures
  • High power density


  • Warranty covers only a short period

4. Odyssey 31-PC2150S Heavy Duty Commercial Battery

Odyssey 31-PC2150S Heavy Duty Commercial Battery

Key Features:

  • High range of CCA makes it usable at extreme temperature
  • 4-year full replacement warranty
  • 3-10 years of service life and 8-12 years of design life


  • Voltage: 12 volts
  • Weight: 77.8 lbs
  • CCA: 1150
  • Capacity: 100 Ah
  • Reserve Capacity: 205 minutes

When looking for the best group 31 deep cycle battery, Odyssey 31-PC2150S is just a delightful piece.

Aside from other features, which point will attract you most is its incredible 1150 Cold Cranking Amps. 1150 CCA makes it suitable for a wide range of temperatures, even in extreme weather. 

And you know the best part?

Keeping in mind the needs of commercial vehicle users, ODYSSEY batteries offer massive starting power, rapid recovery also extreme durability.

For a strong structure with an AGM design, it is sturdily resistant to shock and to tremble. Here, pure lead plates increase their power twice than traditional batteries, while lifetime boasted thrice almost.

What really wondering is………

It can recharge within a short time than you can imagine- only 4-6 hours needed for a full charge. This extreme fast recharge effectively saves your time. Again, to keep your faith, Odyssey is ready for a 4-year full replacement warranty from the 1st date of purchase.

Rare, right?

If you are looking for a sturdy deep cycle battery for heavy commercial use, Odyssey can do your task without inconvenience. From tractor-trailers to farming, construction equipment to RVs, buses, cargo vans to emergency responses- Odyssey can get the job done, can’t it? So, what are you waiting for?


  • Very easy to install
  • Odyssey offers four years warranty that is unusually seen


  • A little bit pricey

5. Banshee Marine Battery

Banshee Marine Battery

Key Features:

  • Flip- Up handle makes it handy
  • It comes with a hydrometer to monitor battery life
  • High reserve capacity with less self-discharge rate


  • Voltage: 12 volts
  • Weight: 52.6 lbs
  • Amp Hours: 105 Ah
  • Cold Cranking Amps: 900
  • Reserve Capacity: 190 minutes

After deciding on purchasing the Banshee Marine battery, you will be surprised to see unique features like a dual post terminal, handles for easy carrying, and a built-in hydrometer.

No doubt about it!

Even on a cold winter morning, this heavy-duty battery is not lazy. Rather, it can actively fire up your vehicle.

Banshee wisely used only up to date materials while manufacturing the battery. That makes it reliable, powerful enough to offer to crank, igniting, lighting needs.

Beyond that, Banshee takes security and sturdiness to the next level. None can report about their safety because of leak-proof AGM design. It has a good recharge capability to provide enduring performance.

And can withstand 400 charge-discharge cycles to 80% depth of discharge.

Too good!

Through a built-in hydrometer, you can monitor the current state of your battery quickly. It is completely sealed to avoid the need for the addition of water.

Most importantly, Banshee Marine batteries come with more battery plates that lead to a large surface area. It indicates that you get approximately twice more power than other competitor marine batteries.

This battery will also come with high recommendations though it is not an AGM battery. It has a longevity of about 5 to 6 years that cross the AGM battery.


  • Affordable price
  • 80% depth of discharge
  • twice more power


  • Reverse power is a pure bullshit

What Does Group Size Mean on A Deep Cycle Battery?

Before anything else, let’s discuss What is the meaning of Battery Group Size?

The meaning of the “Group size” goes for the battery’s physical holder size. It is just a specification which you can find on all batteries.

It is the physical measurement of the battery’s casing as set by the BCI. The height, width, and also length of the battery specify the group of the battery size.

Here have some factors you have to keep in mind about the group sizes, like:

  • A smaller battery group size typically indicates a large battery.
  • Conversely, a big battery group size indicated a smaller size battery.

A Wide-ranging Explanation

A battery group size submits to the battery’s physical dimensions, including:

  • Length
  • Width
  • Height

The BCI built this battery dimension chart to normalize the industry. The group size is standard based on the brand where need to trust. Below has a map of different group sizes.

BCI calls for minimizing the number of modifies the chart, but adjustments will be constructed over the years. If you think of going for the new battery, confirm the older battery’s group size with updated specifications.

Group SizeLengthWidthHeight
Group 259-1/16-inches6-7/8-inches8-7/8-inches
Group 3113-inch6 -13/16-inch9-7/16-inch
Group 359-1/16-inch6-7/8-inch8-7/8-inch

How Many Amp Hours Is A Group 31 Battery?

Do you know, what is AMP-Hour?

All deep cycle battery is always rated in AMP-hours. An AMP hour is referred one for one hour or 10-AMP for 1/10 of an hour.

It is for amps X hours. If you have anything that pulls 20-AMPS and use it for 20-min, the amp-hour can be sued for 20-amps x .333-hours.

How heavy is a group 31 battery?

We usually allow the AH rating time for the battery and backup power system for a 20-hour rate. It discharges down to 10.5 volts over 20-hour while the total AMP hours it provides is measured.

Here is the kicker:

Sometimes rating at the 6-hour rate and 100-hour rate both of them give for comparison for several applications.

The 6-hour rate is always used for any commercial or industrial battery’s regular daily duty cycle. And the 100-hour rate is given to make the battery look better than it truly is.

But it is helpful for outline battery capability for long-duration backup AMP-Hour needs.  

Why is AMP-Hours definite at an impressive rate?

It happens for the Peukert Effect.

The value of Peukert is associated with the internal confrontation of the battery. The quicker a battery expulsion, the LOWER the AH capacity. Conversely, when the drain is slower, the AH capacity will higher.  It is beneficial for commercial use.

Battery Size Codes

Batteries always come in different sizes and groups that mainly depend on the physical size plus terminal placement. But it is not measured for battery capacity. The group code starts at 24, 27, 31, and so on.

What is the difference between Group 27 and Group 31 batteries?

Some standard battery size code charts have shown below.

Group-2470-85 AMP Hours12-voltages
Group-2785-105 AMP Hours12-voltages
Group-3195-125 AMP Hours12-voltages

Types of best Group 31 Battery

Group 31 batteries come with different types of batteries that differ based on the construction system.

Remember this

A portable battery is an essential part of your favorite vehicle because they help to start engines quickly and preserve energy more efficiently.

Try to understand every type of Group 31 that will ensure what you are getting the correct battery or not depends on your requirement.

AGM Battery:

  • Higher vibration application
  • Higher upfront cost than flooded cells
  • Spill-proof design
  • No maintenance
  • Mount in any direction
  • Faster charging
  • Longer lifespan
  • More sensitive heat

Flooded Cells:

  • Low vibration application
  • Least upfront cost
  • More Maintenance required
  • Heat sensitive
  • Susceptible to electric shorts

Gel Batteries:

  • Added Silica
  • Easily Overcharge
  • Deep Cycle application
  • Long & Low power operation
  • Solar equipment
  • Off The Grid Application

Final view

Before diving into the lake of information, consider your needs and go through the tips attentively to quickly determine which company battery best suits your vehicle.

At the same time, a low-quality battery can ruin your journey and get you in great trouble. So, you must ensure the best quality of your battery before you depart. You will surely enjoy it as you pay.

Our above information will let you experience the best batteries manufactured by the world’s top-rated companies and help you make the perfect choice to meet your purpose perfectly.

So, why delay?

Go ahead and give a go to the best group 31 deep cycle battery you have met above.

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