Group 31 batteries come in a variety of types and sub-types for all different heavy-duty equipment. From batteries that are best in severe weather to batteries that are best for the high vibrations of road construction, knowing what Group 31 battery fits your fleet needs can be difficult, especially if you are wanting to upgrade to a more efficient battery and aren’t sure what will work with your application. That’s why we are here to help explain the differences in Group 31 batteries and the benefits that each will offer.
In this article, we will review:
- What are Group 31 Batteries?
- Are There Different Group 31 Battery Types?
- Group 31 Batteries to Provide Extra Boost
- 6 Easy Ways to Make Your Batteries Last and Save You in The End
- Replace Your Old Batteries with New Ones on The Market
What are Group 31 Batteries?
Group 31 batteries are an industry standard commercial battery for heavy duty trucks in all uses and vocations. Most often, multiple batteries are utilized in parallel configuration to accommodate engine cranking, truck accessories, and other power demands of the truck and equipment.
Did You Know? Batteries are the most recycled item in North America! Even more so than aluminum cans.

Most Group 31 batteries today are sealed, vented, and maintenance free and require little more than keeping battery connections clean and tight. Group 31 actually refers to the physical dimensions of the battery casing. The case size does not directly affect the Amp Hours (Ah), but there is a correlation that with a larger case size, there would be a higher capacity.
Watch this Commercial Group 31 Batteries video to learn more.
Are There Different Group 31 Battery Types?
Group 31 batteries can come in a variety of different battery construction types. While most Group 31 batteries are lead-acid based, they break down into different product types based on how they are constructed. Understanding each Group 31 battery type will help ensure you are getting the correct battery for your application needs.
AGM Batteries
Absorbent Glass Mat (AGM) Batteries are some of the most underappreciated battery types on the market today. Picking up in popularity in the early 1980s, AGM batteries helped to reduce weight and improve reliability for the military and UPS. With a proven longer lifespan and up to 5 times faster charging than Flooded Cell batteries, it’s a no brainer why the US Military, UPS, and NASCAR were some of the first to switch to AGM batteries.
AGM Batteries are constructed similar to Flooded Cell batteries but are completely sealed. They also have fine fiberglass mats between the lead and lead-oxide that helps soak up loose sulfuric acid within the battery casing, creating a spill-proof design. The fiberglass mats also help ensure the lead and lead-oxide plates do not touch to create an electrical short. AGM batteries are vibration resistant thanks to those fiberglass mats. AGM batteries can also be mounted in almost any direction, making them ideal for motorcyclist, ATVs, and other recreational vehicles.
Nothing is worse for any battery type than extreme heat. Traditional AGM batteries are heat sensitive and cannot be mounted near the engine because of the high temperatures. They are recommended to be mounted away from the engine, or like-new semi-trucks, under the driver’s seat. Deka’s new Thermal Shielding Fahrenheit Technology extends AGM battery life and offers extra electrical loads in those high heat environments.
AGM batteries are the chosen battery type for NASCAR, UPS, and the US Military because of their vibration resistance, spill-proof design, and reliability.

AGM Battery Summary Points:
- For High Vibration Applications
- Higher Upfront Cost than Flooded Cells
- Spill-Proof Design
- No Maintenance
- Mount in Any Direction
- Faster Charging
- Longer Lifespan
- More Heat Sensitive
Flooded Cells
Flooded Cell batteries are constructed of lead and lead-oxide plates held vertically by deep-pockets to keep the plates from touching. These batteries contain loose sulfuric acid within the battery casing that causes a chemical reaction with the lead and lead-oxide plates, creating an electrical current. Flooded Cell batteries require you to mount them as level as possible and in the upright position.
Being widely used, Flooded Cell batteries are generally the cheapest battery on the market but require more maintenance from the user. You may have to add distilled water or even the battery acid before the battery is operable. Flooded Cell batteries are also more susceptible to electrical shorts that will ruin your battery, thanks to high vibrations. The lead and lead-oxide plates may touch due to high vibrations, creating a short circuit, leaving your battery burnt up and leaving you stranded.

Flooded Cell Battery Summary Points:
- For Low Vibration Applications
- Least Upfront Cost
- More Maintenance Required
- Susceptible to Electrical Shorts
- Heat Sensitive
Gel Batteries
Gel batteries are constructed almost identical to Flooded Cells batteries but contain a silica additive to set or stiffen the acid inside. The Gel batteries are the most sensitive battery you can buy. Gel batteries can easily be overcharged, creating poor performance and premature failure. Now that does not mean they are not a good battery; you just must know the applications to use them with. Gel batteries are best used for deep cycle applications, such as electric fences, solar panels, Emergency Power Supplies, and other off-the-grid applications.

Gel Battery Summary Points:
- Added Silica
- Easily Overcharge
- Deep Cycle Applications
- Long, Low-Power Operations
- Solar Equipment
- Off -The-Grid Applications
Group 31 Battery Functions and Characteristics
Group 31 batteries also have different functions or performance characteristics that are necessary for your truck’s demands. This is usually dictated by the application. In heavy duty truck applications, your batteries need to perform varying functions such as heavy engine cranking, long term or sustained current demand, and also high repetition cycles of starting. For those reasons, different balances of these needs are reflected in the engineering of varying specs within the Group 31 family.
Dual Purpose
Dual Purpose Group 31 batteries are the most common battery you will find in the Group 31 size. They offer a strong middle ground for both True Starting and Cycling/ Deep Cycling properties. Dual Purpose Group 31 batteries have strong starting currents to get you going, while also featuring a strong deep cycle discharge; meaning you can run it longer with a lower current. Good Dual Purpose Group 31 batteries will provide at least 900 CCA and 100 Ah.
Cycling/Deep Cycling
Group 31 batteries can also come in a Cycling/ Deep Cycling version. These batteries are more designated for electric vehicles, marine, or off-the-grid applications. Cycling/ Deep Cycling Group 31 batteries provide excellent low current discharge to keep your battery lasting for quite a while. They do not provide a strong starting current and thus are not great options for applications requiring high CCA’s, MCA’s, and HCA’s.
Check Out The Ultimate Battery Buyer’s Guide!
Find out more about Group 31 Batteries Dimensions, Weights, and Features.
Wheelco Quick Tips: 6 Easy Ways to Make Your Batteries Last
Wheelco has some simple, yet tried and true tips for keeping your battery in top-notch shape even with the extreme high and low temperatures. Give your battery the TLC it needs to keep it running at a high performance and for years to come.
1. Purchase a Quality Battery -Buyer Beware
First and foremost, DO NOT purchase a battery based on price alone. Most often, pricing is influenced by specifications. Variations in cold cranking amps, amp hour rating, and even warranties are the main factors in pricing differences. Generally speaking, you tend to get what you pay for. That’s why it pays to check the specs on batteries. Wheelco proudly carries Deka Batteries from East Penn Manufacturing. Deka Batteries are Made in the USA and can provide you with the ultimate combination of quality, performance, and price.
2. Proper Battery Mounting
Take the proper steps to ensure your batteries are mounted securely within the battery box with the cover intact, and that the battery box brackets are secured to the frame. AGM batteries are made for extreme vibration, even being used by NASCAR, making them the best choice for high vibration activities.
3. Fully Charge Your Battery
Batteries die. It happens. Repeated short driving distances with multiple engine start cycles makes it difficult for your charging system to keep your batteries in an adequate re-charge status. Also, it a very important to consider your charging system. Make sure alternator drive belts are properly tightened and maintained, and that all electrical connections between starter, alternator and batteries are tight and free of excessive corrosion.
4. Keep It Clean
Batteries take some serious abuse, but just like with almost everything, proper maintenance is key to a long-lasting product. Dirt, grease, and grim will trap itself around the battery and cause overheating. Clean your terminals and wipe your battery down with a rag on a regular basis. A toothbrush works wonders to clean the corrosion off the battery terminals if you do not have a battery terminal cleaner. In addition, a good coat of KRL 73 corrosion inhibitor from Krown will help protect and maintain integrity of your battery terminal connections.

5. Turn Devices OFF
We all know that keeping your lights on will quickly sabotage your battery’s life. But what about your phone charger? Or your radio? You might not know but charging your phone or listening to the radio while in idle is wearing down your battery. Make sure to turn off and unplug any devices such as your radio and phone chargers if they remain powered when the key is off.
6. Take Weather into Consideration
Take simple steps to extend your battery’s life. Park in the shade, garage, shop, or shed to offset the extreme weather beating on your vehicle. Some batteries are made for extreme heat or extreme cold, but to keep your batteries lasting longer, offer them some protection from the outside weather. If your truck is typically parked outside, it is a good idea to install a heavy-duty engine block heater to make your cold start-ups easier and less taxing to your batteries. If you know you won’t be using your vehicle for an extended period-of-time, store your batteries inside or somewhere with climate control.
Replace Your Old Batteries with New Ones on The Market
If you need to replace your batteries, replace them with high-quality batteries you can trust. For heavy-duty applications, Wheelco has the batteries stocked for your equipment. We also carry batteries for smaller applications—from your boat, jet ski, or other marine applications to your ATV, golf cart, or other recreational vehicles. Stop in or call one of our multiple locations, or shoot us an email and our experts will match you with the right battery for your application needs.