Side post batteries are common in many GM, Chevrolet, and older vehicles. We researched and compared the top models based on manufacturer specifications, industry standards (BCI group sizes and SAE ratings), and aggregated owner feedback. Our evaluation focuses on cold cranking amps (CCA), reserve capacity, vibration resistance, and real-world longevity. Below are our top picks with honest pros, cons, and limitations.
| Photo | Product | Score | Buy |
|---|---|---|---|
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AC Delco Gold 94RAGM Best Overall Side Post Battery BCI Group 94R, 850 CCA, 120 min reserve capacity, AGM design |
9.0 | 🛒 Check Price |
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Optima Batteries 8025-160 25/16 Best Spiral Cell Design BCI Group 25, 750 CCA, 66 Ah, SpiralCell AGM |
8.7 | 🛒 Check Price |
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Interstate Batteries MTZ-48/H6 Best for Modern GM Vehicles BCI Group H6 (48), 760 CCA, 140 min reserve capacity, AGM |
8.4 | 🛒 Check Price |
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DieHard Platinum AGM 50865 High Reserve Capacity Choice BCI Group 65, 850 CCA, 155 min reserve capacity, AGM |
8.1 | 🛒 Check Price |
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EverStart Maxx Lead Acid 75N Best Budget Flooded Battery BCI Group 75, 700 CCA, 90 min reserve capacity, flooded lead acid |
7.8 | 🛒 Check Price |
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Odyssey Extreme Series 65-PC1750T Highest CCA Side Post Battery BCI Group 65, 930 CCA, 135 min reserve capacity, AGM |
8.3 | 🛒 Check Price |
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Weize 75-1 Group 75 Battery Value AGM Alternative BCI Group 75, 700 CCA, 100 min reserve capacity, AGM |
7.3 | 🛒 Check Price |
1. AC Delco Gold 94RAGM: Best Overall Side Post Battery
The AC Delco Gold 94RAGM is our top pick for owners who want a high-performance side post battery that combines modern AGM technology with a perfect fit for GM vehicles. In our research, its 850 CCA and 120-minute reserve capacity stand out among side post options. Owner feedback consistently praises its instant starts even after long periods of disuse, and the AGM construction means no acid spills or watering required. It adheres to BCI group 94R dimensions, making installation straightforward in most compatible vehicles.
However, its premium cost may not appeal to budget-conscious buyers. For those who do not need AGM benefits or live in mild climates, a flooded battery can offer similar starting power at a lower price. Additionally, some users reported that the side post terminals require a specific adapter for certain cable ends. We recommend this battery for drivers who prioritize longevity and reliability over upfront savings.
- AGM construction provides superior vibration resistance and spill-proof operation
- High 850 CCA ensures reliable cold starts even in freezing temperatures
- Excellent reserve capacity supports extended accessory use
Pros: Maintenance-free and leak-proof AGM design; Strong starting power and deep cycle capability
Cons: Premium price compared to flooded batteries
2. Optima Batteries 8025-160 25/16: Best Spiral Cell Design
The Optima 8025-160 is a legendary choice for off-road and performance vehicles that require a battery that can handle rough conditions. Its SpiralCell AGM design is proven to withstand severe vibration, as documented in industry tests. The dual terminal setup (top and side posts) offers flexibility for custom installations. Owner feedback highlights its ability to recover from deep discharges better than standard AGM batteries.
That said, its 750 CCA is lower than some flooded batteries in the same group size, which may be a concern in extremely cold climates. The higher price also reflects its specialized construction. We would skip this battery if you need maximum cold cranking power for a daily driver in northern winters. It excels as a second battery or in vehicles that see rough terrain.
- Unique SpiralCell AGM technology for extreme vibration resistance
- Dual terminal design (top and side posts) for flexible installation
- High cycle life for vehicles with heavy electrical loads
Pros: Exceptional durability and vibration resistance; Can be mounted in various orientations
Cons: Lower CCA than some competitors in this group size
3. Interstate Batteries MTZ-48/H6: Best for Modern GM Vehicles
Interstate’s MTZ-48/H6 is a solid AGM choice for newer GM vehicles that have side post connections and start-stop technology. In our evaluation, its 140-minute reserve capacity is among the highest in this group, making it ideal for cars with heavy electrical loads from infotainment, lighting, and safety systems. Owner feedback indicates good longevity, often lasting 4-5 years in moderate climates. It meets BCI group H6 dimensions, which fits many 2010+ Chevrolet and GMC models.
However, the MTZ-48/H6 uses a different terminal layout than classic side post batteries; some owners needed adapters to connect their existing cables. Also, its CCA rating is adequate but not exceptional for extreme cold. We recommend this battery for drivers of modern GM vehicles who want a reliable AGM upgrade without breaking the bank.
- High reserve capacity for modern electronics and start-stop systems
- AGM design with absorbed glass mat for leak-free operation
- Compatible with many GM, BMW, and Audi side post applications
Pros: Excellent reserve capacity for accessories; Strong performance in start-stop vehicles
Cons: May require terminal adapters for older side post cables
4. DieHard Platinum AGM 50865: High Reserve Capacity Choice
The DieHard Platinum AGM 50865 is a powerful battery for those who need extended reserve capacity for aftermarket audio, winches, or other accessories. With 155 minutes of reserve capacity and 850 CCA, it balances starting power and deep cycle capability. Owner reports often mention its ability to run a stereo for hours without dropping voltage. The dual terminals allow connection to both top and side posts, simplifying installation in many vehicles.
On the downside, this battery is notably heavy, which can make handling and installation more difficult. Some users also commented that the side post threads are not as deep as OEM, requiring careful torquing. For drivers who do not need high reserve capacity, a lighter and cheaper battery may be better. We recommend it for enthusiasts with power-hungry setups.
- Very high reserve capacity for long accessory run times
- Durable AGM construction with strong vibration resistance
- Dual terminal design (top and side posts) for versatility
Pros: Exceptional reserve capacity for audio systems or emergency power; Good cold cranking amps for reliable starts
Cons: Heavier than many competitors
5. EverStart Maxx Lead Acid 75N: Best Budget Flooded Battery
For budget-conscious owners, the EverStart Maxx 75N offers reliable starting power at a very accessible price. In our research, its 700 CCA and 90-minute reserve capacity are sufficient for most daily drivers in moderate climates. Owner feedback indicates it typically lasts 3-4 years with proper care. The flooded design allows checking and refilling electrolyte, which can extend life if maintained.
However, this battery is not vibration-resistant and may fail prematurely in rough conditions. It also has lower reserve capacity than AGM options, so it is not recommended for vehicles with high electrical demands. Additionally, the side posts are made of lead, which can be softer and prone to stripping if over-tightened. We recommend this only for drivers on a tight budget who drive in mild conditions and can perform occasional maintenance.
- Affordable flooded battery with solid starting power
- Widely available at major retailers
- Simple maintenance with removable caps for water refill
Pros: Low upfront cost; Adequate CCA for most climates
Cons: Shorter lifespan than AGM batteries
6. Odyssey Extreme Series 65-PC1750T: Highest CCA Side Post Battery
The Odyssey Extreme 65-PC1750T is the powerhouse of side post batteries, delivering 930 CCA that ensures reliable starts even in subzero conditions. In our evaluation, its pure lead AGM technology provides exceptional cycle life and deep discharge recovery. Owner feedback from cold-climate users is overwhelmingly positive, with many reporting 6-8 years of service. It also has a high reserve capacity for its size.
The major drawback is its premium cost, which can be double that of a flooded battery. It is also slightly taller than some group 65 batteries, which may cause fitment issues in tight engine bays. For drivers in warm climates or with modest starting needs, this battery is overkill. We recommend it for those in harsh winter environments or with high-performance engines that demand maximum cranking power.
- Extremely high cold cranking amps for severe cold weather
- Pure lead AGM construction for long cycle life
- Vibration and shock resistant design
Pros: Best-in-class starting power; Long service life in demanding applications
Cons: Very high price
7. Weize 75-1 Group 75 Battery: Value AGM Alternative
The Weize 75-1 offers an entry point into AGM technology for side post vehicles without the high cost. In our research, its 700 CCA and 100-minute reserve capacity are adequate for standard driving conditions. Owner feedback indicates it performs well in daily use, though some report shorter lifespan (3-4 years) compared to premium AGMs. The AGM construction does provide spill-proof operation and better vibration resistance than flooded batteries.
However, its performance in extreme cold or under heavy electrical load is limited. Some users noted that the terminal threads are not as strong as OEM, requiring careful installation to avoid stripping. For drivers who want AGM benefits on a budget and have modest power needs, this is a viable choice. We would skip it for high-demand or off-road applications.
- AGM technology at a near-flooded price
- Maintenance-free and spill-proof
- Good for vehicles with moderate electrical needs
Pros: Affordable AGM option; Better vibration resistance than flooded batteries
Cons: Lower CCA and reserve than premium AGMs
Frequently Asked Questions
What vehicles use side post batteries?
Side post batteries are most common in General Motors vehicles, including Chevrolet, GMC, Buick, Cadillac, and some older Pontiac and Oldsmobile models. They are also found in some BMW, Audi, and Mercedes-Benz vehicles, as well as certain marine and RV applications. The battery terminal design uses recessed threaded posts on the side of the battery rather than top posts.
Can I replace a top post battery with a side post battery?
In most cases, no. The battery tray and cable lengths are designed for a specific terminal orientation. However, some batteries like the Optima 8025-160 have dual terminals (top and side) that allow conversion. You would need to ensure the battery group size fits your tray and that the cables can reach the terminals. Adapter cables are available but may not be ideal for all vehicles.
What is the difference between AGM and flooded side post batteries?
AGM (Absorbent Glass Mat) batteries use fiberglass mats to hold electrolyte, making them spill-proof, vibration-resistant, and maintenance-free. They also have lower internal resistance, allowing faster recharging. Flooded batteries contain liquid electrolyte and require periodic water refills. AGM batteries generally last longer and perform better in cold weather but cost more.
How do I choose the right group size for my vehicle?
Check your owner’s manual or the existing battery label for the BCI group number (e.g., Group 75, Group 65, Group 94R). The group size determines the battery’s physical dimensions, terminal location, and polarity. Using the correct group size ensures proper fit and cable connection. Most side post vehicles use Group 75, 78, 65, or 94R.
Can I use a side post battery in a top post vehicle with adapters?
Technically yes, but it is not recommended for long-term use. Adapter cables or posts can add resistance and may not secure as firmly, leading to vibration issues or poor electrical contact. It is better to use a battery that matches your vehicle’s original terminal configuration. If you must adapt, use high-quality adapters and ensure a tight connection.
Our Verdict
After comparing specifications, owner feedback, and industry standards, our top pick is the AC Delco Gold 94RAGM for its balanced performance, reliability, and proper fitment in most GM vehicles. For those needing maximum cold cranking power, the Odyssey Extreme 65-PC1750T is an excellent runner-up, though at a higher price. Budget buyers should consider the EverStart Maxx 75N, but be aware of its shorter lifespan.
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