Group 27 Deep Cycle Batteries: Dimensions, Features, and Recommendations

Published on: August 2, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

For a fresh start with a vehicle-compatible battery, labeled numbers on the batteries reflect the group and size which fit all your vehicle’s deep cycling needs. There you can find some real-life differences between those batteries, for instance, group 24 provides less reserve capacity and cranking amps than group 27 deep cycle battery. Mostly a BCI group 27 battery is variable in deep cycle form to make it stand out from the common crowd. 

group 27 deep cycle battery

Group 27 deep cycle batteries come with 140-220 minutes of reserve capacity which is convenient for golf carts and RV, and sometimes in marine applications supporting Marine Cranking Amps and bank marine battery chargers. Without recharging for a long time, you can operate at ease in the cold temperature too. 

When aiming for a proper group 27 battery replacement, this is worth checking the actual size of both the battery compartment and the old battery, as well as how many watts does a car battery have. However, for the prospective users who are literally searching for a good model to avoid other overwhelming reviews, we have picked the best choices of group 27 deep cycle batteries with detailed information and installation process.   

What Does Group 27 Battery Mean?

A group 27 battery is larger and compiles a huge powerhouse in itself, however, quite similar to a group 31 battery. Prospective users call it a marine starting battery, even possible to find out as a deep-cycle battery that empowers a marine vessel. 

There are used widely, around 90% of the batteries are of BCI 27 batteries. Including auto manufacturers’ use, such a battery is a direct replacement while your vehicle is already being installed with a lead-acid battery. However, different brands maintain their own manufacturing construction and added features rules to get consolidated with the user’s satisfaction.  


Speaking the truth of a group 27 battery, SAE terminal posts are available in older cars of America, for instance, GMs, Hondas, and often in boats. They are not only large in size but also durable to compete with other useful batteries. Mostly, each group 27 battery either deep cycle or a dual-purpose one derives its own capacity from one side of the lead-acid chemical formulation. 

In general, it measures almost 12.5” in length, 6-3/4 inches in width, and 9-⅜” in height. Besides ranging between 66-110Ah with 20h capacity. Capable of providing 140-220 minutes reserve capacity and 600-1000 CCA to maintain any cars on harsh driving time. Furthermore, talking about its similarity with other battery groups, matched with Group 27, Group 27F, and Group 27H labeled batteries in terms of installation tray. 

BCI Group SizeL x W x H (inches)
27 12 1/16 x 6 13/16 x 8 7/8
27F12 1/2 x 6 13/16 x 8 15/16
27H11 3/4 x 6 13/16 x 9 1/4


Industrial Applications

Several industrial applications can be done with the store power of a group 27 battery. Such a BCI group size is not limited to car or marine applications. However, useful to the floor sweepers and electrically-propelled forklifts.

The battery is lightweight and due to its portability, its power outputs are not limited and do not even reach ordinary levels which lead the way to servicing users’ cars for 3 to 4 years, however, proper maintenance we prefer most.  

Marine Applications

Besides powering a sailboat, a couple of marine uses, for instance, empowering smaller marine vessels you can take into account. Even while we were experiencing group 27 labeled similar batteries, we found the strength of this battery group lied in the longer time driving power generation in itself. 

The battery can store any wind power and solar power energy to release later in terms of users’ needs. If you require backup power, you can take into account the reserved energy for both motorhomes and single buildings. 

Some Awesome Group 27 Deep Cycle Batteries: Analysis and Compare 

Group 27 battery is a common group size of the BCI industry. To avoid the overwhelming situation while roaming around the market, we have provided a comparison with enough details of different branded group 27 batteries below for prospective users. 

1. GreenLiFE GL80-80AH Lithium-Ion Battery Group 27

Dimension:  12.13 x 6.77 x 8.7 inches is the dimension of GreenLife GL80-80AH which approximately is the matching height of a group 27 battery. This is a deep cycle battery and has a built-in fully automatic Battery Protection System (BPS). As a result, it can turn off the battery while it is not in use. Even if the battery drainage crosses below 10.5V or is possibly charged above 15.8V. 

Material: LiFePO4 is the genuine battery cell type which is not common while producing another group of batteries. Each battery cell may bolt through circuit board lengths. If the circuit board fails to charge a single wire, the board will turn the line off and let the battery continue working like before. 

Ampere Hours: During our testing time, we have recorded the Ah ranging between 80-88. However, the function normally at 12V can decrease the capacity to work properly at short-circuit operation. 

Cold-Cranking Amps: Rather than MCA, the deep cycle model battery confirms a CCA regarding function with better heat-resistant working capacity limits to 950.  

Reserve Capacity: This has ranged between 200-210 minutes reserved capacity to maintain your car motors properly in cold-weather eventually. 

Terminal Position: What about the terminal position? Well, both positive and negative terminal posts are direct respectively right and left. 

What we liked 

  • Weighs only 28 pounds which increases the portability;
  • Charges quickly;
  • Durable;
  • Different and sturdy material in construction. 


  • Found nothing. 

2. Mighty Max B00S2MDZFK Group 27 Battery

Dimension:  12.09 inches x 6.65 inches x 8.48 inches. The dimension is only for the screws of the battery. In that case no worry, however, neither mounting nor wire harness is possible. 

Battery Cell Type: This is an AGM cell type battery. In fact, this 30H labeled Lead-acid battery is not only maintenance-free but also UL certified. Such an AGM or SLA spillproof tech-covered battery gives a high discharge rate. 

Ampere Hours: Ranged to 100Ah to maintain the car fresh and let snow drive. 

Cold Cranking Amps: CCA is the utmost feature that regulates the car operating system. This is a feature that matters when starting a car engine or motor and this model has been tested with 900CCA. 

Reserve Capacity: It does not make any noise or vibration, however, the usage of unregulated  Transformer-Based Charger results in output drops and voltage increases. 

Terminal Position: Directs to right-left respectively positive and negative terminal posts to get connected with the engine. 

What we liked 

  • Logical battery dimension;
  • Maintenance-free;
  • Leakage proof.


  • Heavy-weighted, approximately 64 pounds;
  • Not suitable for a small battery. 

3. Powerstar SLA1185BCI Group 27 Deep Cycle Battery 

Dimension: Another sealed battery from renowned battery manufacturer, Powerstar. 13 x 6.6 x 8.62 inches dimension a great fit for small battery trays even. Leads to perfect replacement for Solar, UPS, Alarm System, RV, Wheelchair, and More. 

Battery Cell Type: It has sealed construction that ensures zero electrolyte leaks through the case or its terminals. The fine mat separators such as glass fiber let sufficient electrolyte absorb. Classified as a non-spillable battery to meet the standard requirement of the International Air Transport Association.

Ampere Hours: 100 ampere-hours is the highest rated PowerPoint. 

Marine Cranking Amps: Suitable for marine applications rather than the previous 2 deep cycle group 27 battery models. The MCA is rated 1080 to hit the specific gravity to add water or the electrolyte. 

Reserve Capacity: During our testing time, rated to 190 minutes ranging from 180 minutes. However, this helps prolong the battery even if you drive on snowy or harsh roads. 

Terminal Position: Besides providing long life in cyclic or float services, the sealed construction is open to using any position for negative and positive terminals. 

What we liked 

  • Leakage proof;
  • Robust construction;
  • Maintenance-free;
  • Mounting in any position is possible;
  • Fits any battery tray. 


  • Gas recombination issue occurs;
  • Heavy-weighted. 

4. Universal Power Group 27 Deep Cycle Battery 

Dimension:  12.17 inches x 6.61 inches x 9.16 inches. Maximum dimension fits any small battery too, yet a good notice to keep choice on fixed size. 

Battery Cell Type: SLA/AGM battery cell ensures zero maintenance after a long drive, including a robust sealed construction. Fiberglass technology is absent and does not mean to reduce the durability as the previous model maintains. 

Ampere Hours: Better than the previous model, consisting of 100Ah which maximizes the capacity of car motor power. 

Cold Cranking Amps: We think the cranking amps were depending on solar kit use, for instance, we were applying an inverter to convert the 12V DC group 27 battery current into 11V AC. then possibly it happened. 

Reserve Capacity: Ranging between 170-190 minutes which is far better than the Powerstar group 27 battery model. 

Terminal Position: Similar to the previous battery model, we got battery terminals from AutoZone which users also can fix at any position inside the tray.  

What we liked 

  • Lightweight;
  • Robust construction;
  • Flexible terminal positions;
  • Better reserve capacity. 


  • Found nothing. 

5. VMAX MR127-100 Group 27 Deep Cycle Marine Battery

Dimension:  The core of the VMAX physical dimension is kind of different from other models except for the rest of the features. Comes with a standard group 27 battery model, yet we can say quite better than the previous model. 

Chemistry or Battery Material: It is superior to the wet lead-acid batteries, designed Absorbed Glass Matt (AGM) between the construction using plates. Moreover, it adds many electrical and physical dimensional advantages to not let the electrolyte get consumed. 

Ampere Hours: No differences we have found in previous and this VMAX model’s ampere-hours calculation. Certified with 100Ah from the beginning of applications. 

Marine Cranking Amps: Tested and rated to 800MCA which is better than other MCA rate holding batteries. This is enough reason to put it in the last position. 

Reserve Capacity: Ranged between 180 to 200 minutes and we found the highest reserved capacity to absorb shocks and release zero vibration. 

What we liked 

  • Charges quickly;
  • Advanced technology in construction;
  • Non-spillable and non-hazardous. 


  • Low cranking amps for marine purpose;
  • Heavy;
  • Expensive. 

Our Selection 

Oru first while selecting a BCI group 27 battery is its dimension because dimension shows the appropriate length, height and width of that battery to become a great or worst fit for your battery. As per the dimension, GreenLiFE GL80-80AH we have found a far better match as a battery of group 27. As long as we are concerned that the appropriate dimension of such a battery, especially the height should range between 8.5” to 9” and our first tested battery is fit even for small trays. 

Next prior to opting out the fact is the battery material or chemistry. In this case, a Powerstar did not only work like mighty and robust construction but also its overall wrapping with fine mat tech or according to the popularity with FiberGlass, protection took it to the next level.

Here our concern about the battery ampere and cranking amps was about regular purposes like old American cars. But our enlisted deep cycle batteries of this group are available in Marine Cranking Amps form. Regarding that ampere-hours, each of the models performed the best. However, in terms of CCA and MCA testing, different models’ temperature resistance should not drop below 7.2V at 32°F (0°C). 

Our experience says that the direction of the terminal posts, the right-left position is almost flexible in every model. But we loved it most while testing GreenLife, Mighty Max, and Universal Power Group battery models. 

FAQs of the Group 27 Batteries 

How Many Amp Hours Are in a Group 27 Deep Cycle Battery?

85-105 Amp hours of 12 volts of deep cycle battery can produce more than electrodes based on the physical size and terminal placement. But you should remember that this measure is not to disclose the battery capacity. Industrial batteries are always designated by a part of a number, for instance, FS means a Floor Sweeper.   

What Is the Longest Lasting Deep Cycle Battery?

In general, a different group of batteries has different cell materials, but mostly the Lithium-ion ones made of LiFePO4 is the most robust one that has been proven on different battery certification tests. Next, we can consider an AGM battery that is compatible with different areas to let your car engine start instantly. 

The significant compatibility of such a deep cycle battery is often legible up to 2 years with almost zero maintenance cost because the construction can saturate about 95% rather than full soaking battery types. Besides, an AGM material battery is also popular as a starved electrolyte and 99% efficient which means to combustion entirely with Hydrogen and Oxygen. 

What is the Expected Life Cycle of Group 27 Deep Cycle Batteries?

Group 27 deep cycle batteries are designed to last up to 5-7 years with regular maintenance. The life cycle of the battery is dependent on how it is used, how it is maintained, and the environment in which it is stored. Proper maintenance can help extend the life of a deep-cycle battery, including regular cleaning and ensuring the battery is charged and stored properly.

Group 27 or Group 24?

Rather than group 24 batteries, group 27 batteries hold a better ampere-hours measure to keep up with the other deep cycle battery groups together. The specification is just a product code, a group code to fit the electrolyte and motor tray in certain cars or motorboats. So, for better values, we recommend as per our experience group 27 deep-cycle batteries. 

What is the Size of Group 27 Deep Cycle Batteries?

Group 27 Deep Cycle Batteries typically have a capacity of approximately 75-85 Ah (amp-hours). They measure approximately 12.9 inches (length) by 6.6 inches (width) by 8.9 inches (height).

Final Words 

Paying attention to the battery letters and numbers as if both views can change a wide range in order to purchase a battery for your car or other vehicles. Such a deep cycle features and advantages compatible battery group is BCI 27 battery. While subjected to shock absorption and vibration, the group 27 battery provides a huge power output. 

Either your vehicle requires a large compartment featuring a battery for regular charging and top performance. All included in one group of batteries and that is the BCI group 27 deep cycle batteries. Each of our prospective users may give a thorough reading to purchase the right battery for his/her vehicle. 

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About This Writer

liam jaxon author pic

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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