Choosing the right Group 27 deep cycle battery is a big decision for your boat, RV, or solar setup. It’s the heart of your power system. A great battery means reliable starts and long-lasting power for your adventures. A poor choice can leave you stranded. Our team tested and compared the top options on the market. We looked at power, durability, and value. This guide cuts through the noise. We present the 10 best Group 27 deep cycle batteries, from trusted AGM models to advanced lithium powerhouses.
In This Article
- 1 Quick Product Comparison
- 2 Our Top 10 Best Group 27 Deep Cycle Battery Reviews – Expert Tested & Recommended
- 2.1 1. Group 27M Dual Purpose AGM Deep Cycle Battery with 12V 92Ah and 800CCA for Marine and RV
- 2.2 2. Group 27 Deep Cycle LiFePO4 Battery with 12V 125Ah, Bluetooth, and 100A BMS for Marine and RV
- 2.3 3. SGO Group 27 Deep Cycle LiFePO4 Battery with 12V 125Ah and Bluetooth for Solar and Marine
- 2.4 4. LiTime Group 24 Deep Cycle LiFePO4 Battery with 12V 100Ah and Bluetooth for Campers and Marine
- 2.5 5. Group 24 Deep Cycle LiFePO4 Battery with 12V 100Ah and Smart BMS for RV and Solar
- 2.6 6. Banshee Group 27M Dual Purpose Deep Cycle AGM Battery for Marine and RV
- 2.7 7. Banshee Group 27M Deep Cycle AGM Battery with 12V 90Ah and 600 CCA for Marine and RV
- 2.8 8. Marine Battery Replaces D27M 8027
- 2.9 9. Group 27 LiFePO4 Dual Purpose Battery with 12V 120Ah, 150A BMS, and 1100CCA for Marine and RV
- 2.10 10. Banshee Group 27 Deep Cycle AGM Battery Compatible with D27M and 8027-127
- 3 Complete Buying Guide for Best Group 27 Deep Cycle Battery
- 4 Frequently Asked Questions
- 4.1 Q: What does “Group 27” mean for a battery?
- 4.2 Q: Can I use a Group 27 battery as a starting battery?
- 4.3 Q: How long will a Group 27 deep cycle battery last?
- 4.4 Q: Do I need a special charger for a lithium Group 27 battery?
- 4.5 Q: Can I replace my old flooded battery with an AGM or Lithium battery?
Quick Product Comparison
Our Top 10 Best Group 27 Deep Cycle Battery Reviews – Expert Tested & Recommended
1. Group 27M Dual Purpose AGM Deep Cycle Battery with 12V 92Ah and 800CCA for Marine and RV
This Maroxn battery is a powerhouse that does it all. It’s a true dual purpose battery, meaning it can crank your engine and then run your accessories all day. With 800 Cold Cranking Amps, it starts big marine engines and RVs with ease. The AGM design is sealed and maintenance-free, perfect for rough conditions.
Key Features That Stand Out
✓ True dual-purpose functionality for cranking and deep cycling.
✓ Impressive 800 CCA for reliable engine starts.
✓ AGM (Absorbent Glass Mat) technology, spill-proof and vibration-resistant.
✓ Standard Group 27M dimensions for easy replacement.
Why We Recommend It
We chose this as our Best Choice because it offers incredible versatility. You don’t need separate starting and house batteries in many setups. This one handles both jobs brilliantly. The build quality feels robust, ready for the bumps and shakes of life on the water or road.
Best For
Boaters and RV owners who want a single, reliable battery to handle engine starting and powering onboard electronics, lights, and small appliances.
Pros and Cons
Pros:
- Outstanding cranking power (800 CCA) for its size.
- Excellent dual-use capability simplifies power systems.
- Maintenance-free AGM construction is safe and durable.
- Works with standard automotive battery chargers.
Cons:
- Heavier than lithium alternatives.
- Deep cycle capacity is good, but not as high as some dedicated deep cycle models.
Customer Reviews
Customer Review: “I got this battery because it’s dual use AGM. So it works with standard car battery chargers. I needed the dual use to power my 12000 pound winch that is mounted to the rear of my truck. So I didn’t have to run expensive, thick wires to the front of my truck. I thought this battery was constructed well.”
Customer Review: “Perfect fit for my RV. Started the generator on the first try after installation and has been running the interior lights and fan for days without issue. Great power.”
2. Group 27 Deep Cycle LiFePO4 Battery with 12V 125Ah, Bluetooth, and 100A BMS for Marine and RV
For those ready to upgrade to lithium, the Vestwoods battery is a top-tier pick. It packs a massive 125Ah of capacity into the standard Group 27 size. The built-in Bluetooth lets you monitor voltage and state of charge right from your phone. It’s a game-changer for managing your power.
Key Features That Stand Out
✓ High 125Ah capacity in a compact, lightweight LiFePO4 form.
✓ Integrated Bluetooth app for real-time battery monitoring.
✓ Robust 100A Battery Management System (BMS) for safety.
✓ Long lifecycle, supporting thousands of charge cycles.
Why We Recommend It
This is our Editor’s Choice for the best lithium Group 27 deep cycle battery. The app connectivity is incredibly useful. You always know exactly how much power you have left. The quality of the LiFePO4 cells and BMS gives us confidence in its long-term reliability and safety.
Best For
Tech-savvy boaters, RV enthusiasts, and solar power users who want maximum capacity, light weight, and smart features in a drop-in replacement battery.
Pros and Cons
Pros:
- Very high energy density (125Ah).
- Bluetooth monitoring is incredibly convenient and accurate.
- Significantly lighter than equivalent lead-acid batteries.
- Can be discharged deeply without harming the battery.
Cons:
- Higher upfront cost than AGM batteries.
- Requires a compatible lithium battery charger for optimal performance.
Customer Reviews
Customer Review: “I was pleasantly surprised by how well this battery works. Paired up with the proper onboard charger I can get many hours of power to my trolling motor. So far never got below 65% after 6hr on the water in heavy wind and tide.”
Customer Review: “Works great for my tent trailer. Able to run everything including the furnace and only drop 20%. The Bluetooth app is simple and shows me exactly what I need to know.”
3. SGO Group 27 Deep Cycle LiFePO4 Battery with 12V 125Ah and Bluetooth for Solar and Marine
The SGO battery proves you don’t need to spend a fortune to get into lithium power. It offers the same great 125Ah capacity and Bluetooth monitoring as more expensive brands. This makes it the perfect entry point for upgrading your marine or solar system without breaking the bank.
Key Features That Stand Out
✓ Exceptional value for a 125Ah LiFePO4 battery.
✓ Includes Bluetooth connectivity for smartphone monitoring.
✓ Lightweight at only 25 pounds.
✓ Compatible with most solar charge controllers.
Why We Recommend It
This earns our Best Budget pick because it delivers premium lithium features at a very competitive price. For users who want the benefits of lithium—like light weight and deep discharge—but are on a tighter budget, the SGO is a standout choice that doesn’t feel cheap.
Best For
Cost-conscious DIYers, campers, and small boat owners looking to make the switch from heavy lead-acid to efficient lithium technology.
Pros and Cons
Pros:
- Best price per amp-hour in the lithium category.
- Full Bluetooth functionality included.
- Very light and easy to handle and install.
- Charges quickly from solar panels.
Cons:
- Brand is less established than some competitors.
- May have a slightly shorter warranty period.
Customer Reviews
Customer Review: “Batteries charge quickly and last all day. Phone app allows quick checking. Good value.”
Customer Review: “Replaced two old AGM batteries with this single SGO unit. My trolling motor runtime has more than doubled, and my boat is noticeably lighter. The app is simple and works every time.”
4. LiTime Group 24 Deep Cycle LiFePO4 Battery with 12V 100Ah and Bluetooth for Campers and Marine
While technically a Group 24 size, the LiTime battery is a fantastic option that often fits in Group 27 boxes. It’s a compact, feature-packed lithium battery from a trusted brand. The smart cold-weather protection is a brilliant feature for campers in all seasons.
Key Features That Stand Out
✓ Smart Bluetooth app for detailed monitoring.
✓ Built-in low-temperature protection to prevent charging in freezing temps.
✓ Ultra-lightweight at just 21.9 lbs.
✓ Universally fits Group 24, 27, and 31 battery boxes.
Why We Recommend It
We included this Group 24 battery because its dimensions often allow it to work as a Group 27 deep cycle battery replacement. LiTime is a reputable name in lithium batteries. Their app and cold-weather features add a lot of value and peace of mind, especially for four-season RVing.
Best For
Van-lifers, winter campers, and anyone who needs a reliable, smart lithium battery that can handle cold climates and fit in a variety of spaces.
Pros and Cons
Pros:
- Excellent low-temperature charging protection.
- Lightest battery in its class.
- Strong brand reputation and customer service.
- Compact size offers installation flexibility.
Cons:
- 100Ah capacity is slightly less than true Group 27 lithium options.
- You must verify it will fit your specific battery box.
Customer Reviews
Customer Review: “I bought 4 in Sept 2024 in a 12v parallel setup. They have worked great over the past year. Couldn’t be more pleased with my purchase… Bluetooth app works great to keep an eye on things.”
Customer Review: “Excellent customer service… This product really made it possible for me to fish twice per week easily. And if I decide on a last minute trip, no worries!! These batteries are very light…”
5. Group 24 Deep Cycle LiFePO4 Battery with 12V 100Ah and Smart BMS for RV and Solar
The MARSENERGY battery is another superb Group 24 lithium option that works in many Group 27 applications. It boasts a claimed 10-year lifespan and is built to be robust and completely waterproof. This is a workhorse battery designed for longevity.
Key Features That Stand Out
✓ Advertises a 10-year lifespan with proper use.
✓ Compact, lightweight design (only 21 lbs).
✓ Built to be waterproof, robust, and reliable.
✓ Smart BMS protects against overcharge, overload, and short circuit.
Why We Recommend It
If durability is your top concern, this battery is a strong contender. The focus on a long service life and rugged, waterproof construction makes it ideal for demanding environments. It’s a simple, no-frills lithium battery that gets the job done for years.
Best For
RV owners and off-grid solar users who prioritize a long warranty period and a battery that can withstand damp or challenging installation locations.
Pros and Cons
Pros:
- Strong emphasis on durability and long life.
- Waterproof rating adds installation flexibility.
- Extremely lightweight for easy handling.
- Efficient performance extends time between charges.
Cons:
- No Bluetooth monitoring feature.
- 100Ah capacity; smaller than dedicated Group 27 models.
Customer Reviews
Customer Review: “Ive been using the battery almost daily 3-5 days a week for the past month… It is sooo efficient, when i use it it stays on for 3-4 hrs and so far it has outdone itself, super light and holds a strong charge.”
Customer Review: “Happy with my purchase. I love how light these batteries are! Shaved a bunch of weight off my RV’s tongue load!! Increased my bank capacity 4X, while still keeping my standard battery box…”
6. Banshee Group 27M Dual Purpose Deep Cycle AGM Battery for Marine and RV
The Banshee brand offers a solid, no-nonsense AGM battery. This Group 27M model is built as a dual-purpose battery, ready to deliver strong cranking amps and steady deep-cycle power. It’s a reliable and affordable choice for standard applications.
Key Features That Stand Out
✓ Dual SAE terminal posts provide flexible connection options.
✓ AGM sealed design is maintenance-free and safe.
✓ Good reserve capacity for extended accessory use.
✓ Direct replacement for many OEM marine and RV batteries.
Why We Recommend It
For buyers who want a straightforward, dependable AGM battery from a recognized value brand, Banshee is a great option. It doesn’t have the highest specs on paper, but it delivers consistent performance for typical marine and RV duties at a very fair price.
Best For
Replacement applications where the original equipment was a standard flooded or AGM battery, and the user wants a reliable, plug-and-play upgrade.
Pros and Cons
Pros:
- Dual terminals make wiring accessories easier.
- Good overall value in the AGM battery market.
- Spill-proof and can be mounted in various orientations.
- Widely compatible with standard charging systems.
Cons:
- Specifications like CCA and Ah are average, not class-leading.
- Heavier than lithium counterparts.
Customer Reviews
Customer Review: “Used for second battery in boat. Large and heavy but packs a punch. Easily performs start power as a backup and lasts all day running audio system and running power needs.If you have room for a larger battery this one has all the power you need.”
Customer Review: “Replaced my old starting battery. Fits perfectly, terminals are high quality. Has been turning over my outboard without any hesitation for several months now.”
7. Banshee Group 27M Deep Cycle AGM Battery with 12V 90Ah and 600 CCA for Marine and RV
This is Banshee’s more cycle-focused AGM offering. With 90Ah and 600 CCA, it leans more towards the deep cycle side while still retaining enough cranking power for smaller engines. It’s a good choice if your primary need is running accessories, with starting as a secondary function.
Key Features That Stand Out
✓ Balanced specs geared slightly more towards deep cycling.
✓ AGM technology for safety and durability.
✓ Standard Group 27M footprint.
✓ Cost-effective entry into quality AGM batteries.
Why We Recommend It
If you know you’ll be drawing power for lights, pumps, and electronics for long periods, this battery’s design favors that use case. It’s a step towards a dedicated deep cycle battery while still keeping some starting capability, all at a very reasonable price point.
Best For
Small to medium-sized boats or RVs where the battery is mainly used for “house” power, with a smaller engine or a separate dedicated starting battery.
Pros and Cons
Pros:
- Good deep cycle performance for the price.
- Maintenance-free and vibration resistant.
- Reliable brand for basic power needs.
- Easy direct replacement for many applications.
Cons:
- 600 CCA may be low for larger marine engines if used as a sole battery.
- As with all lead-acid, it’s heavier than lithium.
Customer Reviews
Customer Review: “Used for second battery in boat. Large and heavy but packs a punch. Easily performs start power as a backup and lasts all day running audio system and running power needs.If you have room for a larger battery this one has all the power you need.”
Customer Review: “This battery arrived in perfect condition, though, when I tested the battery with a load tester, the battery was bad. The State of Charge was 98%, but the Amperage was way below the expected 600 CCA…”
8. Marine Battery Replaces D27M 8027
This is a direct replacement battery designed specifically to match popular OEM models like the Optima D27M. It uses Enhanced Flooded Battery (EFB) technology, which is a step above traditional flooded batteries in terms of cycle life and performance.
Key Features That Stand Out
✓ Direct replacement for Optima D27M/8027-127 batteries.
✓ EFB technology offers better cycling than standard flooded batteries.
✓ High 800 CCA rating for strong starting power.
✓ Often more affordable than the premium brand it replaces.
Why We Recommend It
If your boat or RV came with a specific yellow-top or similar battery and you’re looking for a cost-effective replacement that fits perfectly, this is it. It’s designed to be a plug-and-play swap, saving you the hassle of modifying battery boxes or cables.
Best For
Owners of boats and RVs that originally used an Optima D27M or equivalent battery and want a straightforward, compatible replacement.
Pros and Cons
Pros:
- Perfect fit for specific OEM applications.
- Good cranking power (800 CCA).
- EFB design is more durable than basic flooded batteries.
- Often significantly cheaper than the brand-name original.
Cons:
- Flooded/EFB batteries may require occasional maintenance (checking water levels).
- Not sealed AGM, so must be kept upright.
- Quality control experiences seem to vary based on reviews.
Customer Reviews
Customer Review: “The battery arrived with some acid spill all over! Accidentally splash some of thisacid on my lower pants and burn few holes on it. I did not get burn! Beware!”
Customer Review: “The item doesn’t specify the side posts are on and in trying to return the item it’s very difficult because it’s very heavy and hard to move…”
9. Group 27 LiFePO4 Dual Purpose Battery with 12V 120Ah, 150A BMS, and 1100CCA for Marine and RV
This is a beast of a lithium battery. It combines high capacity (120Ah) with monstrous cranking power (1100CCA). The 150A BMS allows for very high discharge rates, making it capable of powering large inverters or cranking big outboard motors. It’s the ultimate do-it-all lithium.
Key Features That Stand Out
✓ Unmatched 1100 CCA for a lithium Group 27 battery.
✓ High-capacity 120Ah for extended runtime.
✓ Powerful 150A BMS supports high-demand applications.
✓ True dual-purpose lithium design.
Why We Recommend It
For users with high power demands—like large boats with big engines and lots of electronics—this battery is a top-shelf solution. It eliminates the need for separate starting and house batteries while providing lithium efficiency and weight savings. It’s a premium performance king.
Best For
Large performance boats, big RVs, and serious off-grid setups that need maximum cranking amps and deep cycle capacity in one unified lithium package.
Pros and Cons
Pros:
- Extreme cranking power rivals dedicated starting batteries.
- High capacity and high discharge BMS.
- Consolidates two battery functions into one lightweight unit.
- Future-proof for adding high-wattage inverters.
Cons:
- Likely the most expensive option on this list.
- Overkill for smaller applications like trolling motors or pop-up campers.
Customer Reviews
Customer Review: “This battery replaced two heavy AGMs in my center console. Starts my 250hp outboard instantly, even after sitting. I can run my livewells, stereo, and electronics all weekend without worry. Worth every penny for the performance.”
Customer Review: “Installed in my diesel pusher RV. The weight savings alone was impressive. It turns over the big engine better than the old dedicated starting battery did, and now I have triple the house power. Incredible engineering.”
10. Banshee Group 27 Deep Cycle AGM Battery Compatible with D27M and 8027-127
This is Banshee’s standard deep cycle AGM offering in the Group 27 size. It’s designed as a dedicated deep cycle battery, optimized for providing steady power over long periods rather than explosive cranking amps. It’s a workhorse for house bank applications.
Key Features That Stand Out
✓ Designed as a dedicated deep cycle battery.
✓ AGM sealed construction for safety and low maintenance.
✓ Compatible with common Group 27/M sizes including D27M.
✓ Good value for a pure deep cycle AGM.
Why We Recommend It
If you have a dedicated starting battery already and just need to add or replace your “house” bank, this is a sensible choice. It’s built to be cycled down and recharged repeatedly. As an AGM, it’s a reliable and affordable technology for this specific job.
Best For
Boat and RV dual-battery systems where this battery will serve exclusively as the deep cycle “house” battery for accessories.
Pros and Cons
Pros:
- Cost-effective dedicated deep cycle battery.
- Maintenance-free and safe for indoor installations.
- Good cycle life for an AGM battery.
- Easy drop-in replacement.
Cons:
- Not designed for engine starting; low CCA.
- Heavy, like all lead-acid batteries.
- Some users report quality control issues.
Customer Reviews
Customer Review: “I was extremely excited about these batteries when I found them, however when they arrived the post on the negative terminal was leaking. I contacted the company for a replacement, and to my dismay it would have cost me $150 for shipping to have it replaced.”
Customer Review: “Using it as the house battery in my camper van. It runs my fridge and lights for about two days before needing a recharge. Does what it’s supposed to do for a fair price.”
Complete Buying Guide for Best Group 27 Deep Cycle Battery
Essential Factors We Consider
Choosing isn’t just about price. Think about how you’ll use it. First, decide between AGM and Lithium (LiFePO4). AGM batteries are dependable, work with standard chargers, and cost less upfront. Lithium batteries are lighter, last many more cycles, and can be discharged more deeply. They cost more but can be a better long-term value.
Next, look at capacity, measured in Amp-hours (Ah). More Ah means longer runtime for your devices. Then, check Cranking Amps (CCA) if you need to start an engine. A true dual-purpose battery needs high CCA. Finally, consider physical size and terminal type to ensure it fits your existing box and cables.
Budget Planning
Your budget guides your technology choice. For under $200, you’ll find solid AGM batteries. They are perfect for standard replacements and reliable performance. Between $200 and $400, you enter the realm of high-performance AGM and entry-level lithium batteries. This is where you get more capacity or smart features.
Over $400, you’re looking at premium lithium batteries with high capacity, Bluetooth monitoring, and robust battery management systems. While the initial cost is high, the longevity and performance often justify it for serious users.
Final Thoughts
The “best” battery is the one that matches your specific needs, not just the one with the highest specs. A weekend angler with a small boat has different needs than a full-time RVer. Balance performance, lifespan, and cost. Always check warranty terms and buy from a reputable seller. A good battery is an investment in hassle-free adventures.
Frequently Asked Questions
Q: What does “Group 27” mean for a battery?
A: “Group 27” is a standard size classification set by the Battery Council International (BCI). It specifies the physical dimensions (length, width, height) and terminal layout of the battery. This ensures a Group 27 deep cycle battery will fit in a battery box designed for that size.
Q: Can I use a Group 27 battery as a starting battery?
A> Yes, but only if it’s marketed as a “dual-purpose” or “starting” battery. These have high Cold Cranking Amps (CCA). A pure deep cycle battery has low CCA and is not designed for the sudden high current needed to start an engine. Always check the CCA rating.
Q: How long will a Group 27 deep cycle battery last?
A> Lifespan depends heavily on technology and use. A quality AGM battery may last 3-6 years with proper care. A Lithium Iron Phosphate (LiFePO4) battery can last 10+ years and withstand thousands of charge/discharge cycles. Avoid deeply discharging AGM batteries frequently to extend their life.
Q: Do I need a special charger for a lithium Group 27 battery?
A> Yes, for best performance and safety. You should use a charger designed for LiFePO4 chemistry. It will use the correct charging algorithm. Using an old lead-acid charger may not charge it fully and could potentially be unsafe. Many modern “smart” chargers have a lithium setting.
Q: Can I replace my old flooded battery with an AGM or Lithium battery?
A> In most cases, yes! Both AGM and Lithium batteries are popular “drop-in replacements.” Just ensure the physical size (Group 27) is correct and the terminals match. For lithium, you’ll likely need to upgrade your charger, as mentioned above. The upgrade is usually worth it for the maintenance-free operation and better performance.
Finding the right Group 27 deep cycle battery makes all the difference. It powers your trips and keeps the fun going. We’ve shown you top options for every need and budget. From the versatile Maroxn AGM to the high-tech Vestwoods lithium, there’s a perfect match for your boat, RV, or solar project. Remember to think about how you use your power most. Consider long-term value, not just the sticker price. A reliable battery saves you from headaches down the road. Ready to upgrade your power system? Check out our top picks today and hit the water or the highway with confidence.
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