Best AGM Group 34, 34R Battery – Buyer’s Guide

If you have a vehicle that takes a BCI Group 34 or 34R battery, you have many choices. They are a popular battery size for many vehicle brands and marine applications.

Group 34 batteries have the positive terminal on the left. Group 34R batteries have the positive terminal on the right, as indicated by the “R” designation.

Group 34 Battery Dimensions

The sizes and dimensions of group 34 and group 34R are the same: 10.25 x 6.8125 x 7.875 inches, or 260 x 173 x 200 mm (Length x Width x Height). If you have a car that takes a Group 34R battery, you can turn it around in the battery holder and use it in place of a Group 34 battery.

This review will take a closer look at Group 34 and 34R batteries and explore some of our top picks.

Best Choice

Optima Batteries 8004-003 34/78 RedTop Starting Battery

The Best Group 34 and 34R Battery

This battery has dual SAE and GM posts and delivers maximum power over a short time with 800 CCA, helping to start your car reliably on cold mornings. It has a reserve capacity of 100 minutes and will keep running for a long time if the alternator fails.

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Quick Comparison Table

Before we get into a more comprehensive discussion of the best Group 34 and 34R battery replacement choices, let’s take a quick look at their specifications.

Image	Product
Best Choice	Optima Batteries 8004-003 34/78 RedTop Starting Battery Cold Cranking Amps (CCA): 800, Reserve Capacity (RC): 100, Amp-Hours (AH): 50 Battery Group: 34/78 Type: AGM Warranty: 36 Check Price	Check Price
Best Value	Delphi BU9034 MaxStart AGM Premium Automotive Battery Cold Cranking Amps (CCA): 775, Reserve Capacity (RC): 120, Amp-Hours (AH): 50 Battery Group: 34 Type: AGM Warranty: 36 Check Price	Check Price
Also Great	Optima OPT8016-103 Batteries D34M BlueTop Starting and Deep Cycle Marine Battery Cold Cranking Amps (CCA): 750, Reserve Capacity (RC): 120, Amp-Hours (AH): 55 Battery Group: 34 Type: AGM Warranty: 36 Check Price	Check Price
Good Choice	Odyssey 34-PC1500T Automotive and LTV Battery Cold Cranking Amps (CCA): 850, Reserve Capacity (RC): 134, Amp-Hours (AH): 68 Battery Group: 34 Type: AGM Warranty: 36 Check Price	Check Price
Good Choice	Odyssey Batteries 34R-PC1500T Automotive/Light Truck and Van Battery Cold Cranking Amps (CCA): 850, Reserve Capacity (RC): 134, Amp-Hours (AH): 68 Battery Group: 34R Type: AGM Warranty: 36 Check Price	Check Price
Good Choice	ACDelco 34AGM Professional AGM Automotive Cold Cranking Amps (CCA): 740, Reserve Capacity (RC): 115, Amp-Hours (AH): 50 Battery Group: 34/78 Type: AGM Warranty: 36 Check Price	Check Price

Product Reviews

Group 34 and 34R batteries have the same physical size and similar electrical characteristics. All of the batteries on this list have a 36-month warranty and use AGM technology. Each of them has different characteristics and qualities that make them stand out.

1. Optima 8004-003 34/78 RedTop Starting Battery — Best for Durability and Vibration Resistance

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Optima RedTop batteries are designed as a starting battery, rather than a deep-cycle one. They deliver maximum power over a short time, helping to start your car reliably on cold mornings. This battery has dual SAE and GM posts, which means it can accommodate both types of connectors. It has a reserve capacity of 100 minutes, which means that it will keep running for some time if the alternator fails.

Why We Recommend This Battery

We recommend this battery for cold climates where you need reliable starts. It is not intended for deep-cycle charging, so it might not be the best choice for cars and trucks with a lot of electronics. It is resistant to vibration and has a durable case. Its spill-proof design makes it able to be mounted in any position, other than upside down. If your car takes a 34R battery, you can turn this one around, and it will work perfectly.

• Excellent for cold mornings

• Maintenance-free

• Spill-proof

• Durable, vibration resistant

• Strong burst of power

• Heavy, weighs 38.8 pounds

• No carrying handle

• Not for big stereos and heavy electronics

2. Delphi BU9034 MaxStart AGM Battery — Best Value for Price

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The Delphi MaxStart is the most affordable battery on the list. It has 775 cold-cranking amps, which makes it a reliable choice for cold mornings. It weighs 42.5 pounds, and it does have a carrying strap.

The strap was the only drawback that we see with this one. It is a reliable and long-lasting battery, but it is recommended that you pick it up from the bottom, not by the strap. It uses absorbed glass mat technology, which provides excellent conductivity and a consistent power supply.

Why We Recommend This Battery

This battery charges quickly and does not discharge significantly when stored for long periods of time. It has a long life and is a well-made solid battery. Some users report that this battery has lasted for several years beyond its 36-month warranty. The posts are durable and are not likely to rust and break off for many years. The quality of this battery is excellent, and it can be expected to perform well in many different types of cars.

• Affordable

• Reliable as a starter battery

• Vibration and corrosion-resistant

• Absorbent glass mat technology

• Durable, spill-proof

• Thin battery lift strap

• Heavy to move

3. Optima OPT8016-103 D34M BlueTop Deep-Cycle and Marine Battery — Best Marine Battery

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This battery is designed for marine and deep-cycle charging, but you can also use it in your car. This battery’s deep-cycle rating means it is an excellent choice for cars that have heavy electronic loads, like heated seats, bigger stereos, and numerous computer sensors. It also has enough cold-cranking amps to provide reliable starting in extreme temperatures and in high-vibration uses. It is maintenance-free, spill-proof, and is a good choice when starting is critical.

Why We Recommend This Battery

This battery is an excellent choice for recreational vehicles, including boats and RVs. It has excellent starting capabilities, and it is also a good choice for deep-cycle applications, making it balanced for both uses. The heavy polypropylene case is durable and able to withstand shock. The flexibility and wide range of uses for this battery is the main reason why we like it. This model is reported to have a long life, quick charges, and has a long storage life. This makes it an excellent choice for placing your boat in seasonal storage or for cars in long-term airport terminal parking.

• Best for boats and marine applications

• Excellent cold-starting ability

• Good for deep-cycle and heavy electronics

• Durable and able to resist vibration

• Maintenance-free and spill-proof

• No handle for lifting

4. Odyssey 34-PCT1500T Automotive and LTV Battery– Best for Maximum Power

Group 34

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Group 34R

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Odyssey is known for reliable batteries that have a long life, often lasting much longer than the warranty. This one has the greatest power storage capacity of any on the list at 68 amp-hours. Conventional deep-cycle batteries can withstand up to 400 charging cycles. This battery is known to last up to 70% longer, according to user experiences. It recharges quickly and can go from 5% to 80% in about 4-6 hours on the average charger.

Why We Recommend This Battery

This battery excels in many areas. It has excellent cold-starting capabilities, and it is also made to handle a heavy electronic load. It uses spiral-cell technology that increases electrical conductivity and contributes to its long battery life. This one is a little more expensive than others on the list, but its long life and superior performance give it a lower cost over time. The impressive power of this battery is why it made our top picks.

• Powerful, large capacity

• Good for starting and deep-cycle use

• Long battery life

• Heavy-duty handle

• Good cold starting capability

• A little higher price

• Heavy weight, difficult to move

• Painted exterior, can flake off

5. ACDelco 34AGM Professional Battery — Best for Cold Weather

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ACDelco is a brand with a reputation for making batteries that are reliable and long-lasting. This one has the highest cold-cranking amps of any on the list. It has 850 CCA, which means that you can count on it to start your car in the cold weather. It also has 134 minutes of reserve capacity, which means that you have some time to get help if your alternator fails.

Why We Recommend This Battery

We recommend this battery because ACDelco uses advanced technology to produce batteries with excellent power and storage capacity. The battery uses a high-density negative paste that increases battery life. It also uses a calcium-lead positive grid to increase conductivity and lower resistance. This technology increases the power of the battery. The outer casing of the battery is tough and puncture-resistant. It has a vent-cap design that is leak-resistant, too. These improvements add up to a battery that has superior performance and can be expected to have a long life.

• 850 cold-cranking amps

• Long reserve capacity

• Superior technology improves performance

• Durable case

• Long lifting strap can make placement in tray difficult

Buyer’s Guide and FAQ

Group 34/34R Battery

CHOOSE
THE BEST IN 2023

Before purchasing your next battery, it is important to understand terms meaning and how they affect battery performance.

Group 34 and Group 34R batteries are one of the most common types. All of the batteries on this list have similar characteristics in terms of dimensions, cold-cranking amps, and capacity. Even though they have similar characteristics, differences exist between brands and their quality. Here are a few questions that you might have about Group 34 and 34R batteries.

What is an AGM battery?

All of the batteries on this list use Absorbent Glass Mat (AGM) technology. This battery design has many advantages over traditional flooded lead batteries. In an AGM battery, the acid is absorbed in glass mats. The glass mats are sandwiched between a series of lead plates.

AGM Battery

Non-AGM Battery:

The glass mats can be compressed, which allows the manufacturer to pack more plates in the battery. This technique allows them to produce more power and have a longer life. AGM technology and its superiority over flooded lead batteries are among the reasons why all of these batteries made the list.

What is the difference between deep-cycle and starting batteries?

Throughout the review, you might have seen that some of the batteries were better for deep-cycle use, and others were recommended for starting batteries. Starting batteries are known as Starting-Lighting-Ignition (SLI) batteries. This battery is designed to deliver a short but powerful burst of power to start the engine.

A deep-cycle battery is designed to deliver a steady amount of power over a longer time. This is the type of power that is needed for operating electronics. Today’s electronic-laden cars place high demands on the battery. Some of the batteries on this list are good for both deep-cycle and starting applications.

What are cold-cranking amps, and why is it important?

One of the main factors used to evaluate the batteries on this list was cold-cranking amps (CCA). This measures the ability of the battery to deliver a short burst of power in cold weather. This number is a measure of how likely the battery is to be able to start the car on cold mornings. Higher the cold-cranking amps make it more likely the vehicle will be able to start.

What is a Group 34 battery?

Group 34 is a battery designation used by the Battery Council International to describe a battery’s characteristics. It describes the physical characteristics, post locations, and general power characteristics.
A group 34 battery is 10.9 x 7 x 7 inches. They range between 50-68 amp-hours. They can deliver between 750-880 CCA and have a reserve capacity of between 110-134 minutes. Some differences in these characteristics exist between battery brands and types, but most fall within these specifications.

What is the difference between a Group 34 and 34R car battery?

Group 34 and 34R batteries have the exact same specifications, except for the positive terminal position. The R in the number designates that the positive terminal is on the right side of the battery. A Group 34 battery that does not have an R has the positive terminal on the left. You can reverse the battery’s position in the battery tray to allow the cables to be connected to either a Group 34 or 34R batteries in many cases.

Group 34 Positive Red Terminal

Group 34R Positive Red Terminal

What is the best 34/34R battery?

The batteries on this list have different specifications, making them appropriate for different situations. The energy needs of vehicles vary, and the type of battery that is right differs, too. Vehicles that have plenty of electronics to support require a deep-cycle battery. For those in colder climates, cold-cranking amps are more important. It is difficult to consider a certain battery to be an overall winner because the best battery depends on the vehicle’s needs and circumstances.

What does battery Group size 34/78 mean?

Sometimes you will see a battery that is marked as 34/78 or 34-78. A Group 34 and Group 78 battery are almost identical as far as their physical dimensions are concerned, but they differ in the terminals’ position. A Group 34 battery has posts on the top, but a Group 78 battery has terminal posts located on the side.

This is important because of clearance issues with different vehicles. For some, top posts will not allow the hood to close. For others, the battery is such a tight fit width-wise that top posts are necessary. Some vehicles have enough room to take either Group 34 or Group 78 batteries.

What is the difference between a Group 24 and Group 34 battery?

A BCI Group 24 and Group 34 battery are similar in outside dimensions. Many cars that require a Group 24 battery will sometimes upgrade to a Group 34 because they want better starting power. The slight differences between a Group 24 and Group 34 battery mean that sometimes, you will need spacers to install the Group 34 battery terminal into the battery tray.

A Group 24 battery is one inch taller than a Group 34 battery, but the length and width are the same. It should still have a tight fit in the battery tray. The assembly and position of the positive terminal are the same.

What cars, trucks, and other vehicles use a group 34 battery?

A Group 34 battery is recommended for many different types of passenger cars, minivans, trucks, compact SUVs, and full-size SUVs. The list of cars and trucks that use a Group 34 battery is large. A few examples are GM products, Toyota Odyssey, Toyota Scion, Jeep Cherokee, and Chrysler 300M. It will also fit in many classic cars, like a 1963 Corvette. It is one of the most common batteries for passenger cars and vehicles of all types. Many boats use Group 34 batteries that are marine-grade.

Where can I buy a group 34 or 34R car battery?

A Group 34 or 34R battery is one of the easier ones to find. You can usually find one at many national auto parts chains and general merchandise stores that carry auto parts. You can also use the links in this article to find one conveniently and easily.

How many ampere-hours are there in a new 34/34R battery?

Group 34 and 34R batteries range between 50-68 ampere-hours. The brand and quality of the battery determine where a battery falls within this range. If you have a vehicle loaded with modern electronics, you should try to find a deep-cycle type that falls in the upper range of these numbers.

The best way to find this out is to read the individual specifications on the battery you consider purchasing. Always consult your Owner’s Manual about the required specifications for your vehicle. You should only choose batteries that fall within those specifications. Putting a more powerful battery in your car could damage the alternator and electronics. If the battery does not have enough power, it might not start the car and operate the electronics load.

How long does a Group 34 battery last?

The batteries on this list all have 36-month warranties and are top-brands that are known for their longevity. Many factors can affect the actual life that you get from our battery. A battery that is well cared for can last 5 years or more.

If you continually leave the lights on and drain it, then the battery’s lifespan will be reduced significantly. Rapid charging also tends to weaken batteries, as opposed to trickle or slow charges. Some batteries have a longer storage life, but others must receive a more frequent charge from the alternator. Storing your battery at the recommended temperature and avoiding cold will also help to preserve battery life.

Starting with a battery brand known for a long life is the first step in getting the most out of your battery. Brands like ACDelco, Odyssey, and Optima are all known for strict quality control in their manufacturing processes. They also use advanced technology to help them charge quickly and hold a charge for a long time. Purchasing a good battery and taking care of it is the best way to get a long life from your battery.

How do you change a Group 34 battery?

Changing a Group 34 battery is just like changing any other battery. It can be done with a few simple tools. The only thing that you will need is an adjustable crescent wrench or socket set. You will also need a scratchy scrubbie pad or wire brush to clean the battery connectors. You will also need some battery terminal cleaner.

1. Prepare for work. Before you begin the process, make sure that your car is parked on a flat surface, the emergency brake is on, and the engine is turned off. Gather your supplies, lift the hood, and prop it up with the hood support.
2. Remove the connectors from the terminal by using the adjustable crescent wrench or socket set to loosen the hex nut. Remove the negative post first to avoid sparks. You only need to loosen it enough to get it off the post.
3. Remove the battery hold downs or unhook the battery straps.
4. Lift the old battery out of the battery tray. If the old battery has a handle or strap, check it first before using it to ensure it still functions.
5. Inspect and clean. Inspect the terminal connectors, cables, and battery tray for excessive rust. Replace any parts that are needed before continuing. Use a battery terminal cleaner and a wire brush or scrubbie to clean the inside and outside of the battery terminal connector.
6. Put a new battery in place. Carefully lift the new battery and lower it straight down onto the battery holder tray. Make sure that it is all the way in and can’t be moved from side to side. The fit should be secure.
7. Replace battery hold-downs. Reconnect the battery hold-downs and straps. Make sure that the battery is secure and will not move in any direction when you are finished.
8. Reconnect terminal connectors. Place the terminal connectors over the posts and tighten the hex nuts. They should be at the bottom of the post and hand tight. Make sure that they can’t be pulled off or moved up and down.
9. Clean up and start the car. Remove all tools and supplies from around the battery. You can now start the car to make sure that everything is working properly.
10. Dispose of the old battery. Batteries contain lead, acid, and other hazardous materials that can’t be removed by the regular trash collector. You will need to find a recycling center or waste management facility licensed to accept old batteries. Many times, batteries can be recycled, and you can get some money back for your old one.

Final Word

Battery technology continues to improve. Advances in technology give our modern cars some impressive features. All of this new technology requires power. This places a greater demand on battery manufacturers to develop new technology that can meet these devices’ power needs. The batteries on this list were chosen because they represent state-of-the-art battery technology.

The batteries’ advanced technology on this list gives them more power, better charging capabilities, and longer life. They are made for today’s modern vehicle electronics and power needs. The importance of choosing the right battery for your car, the climate where you live, and your electronics use can’t be over-emphasized. All of the batteries on this list are an excellent choice for various needs, making them a good place to start your search for your next Group 34 or 34R battery.

Eric Strong

Eric Strong works in the automotive repair industry more than 12 years. His work included repairing electrical systems in various vehicle systems. A hybrid electric car battery replacement experience expanded his understanding of automotive battery technology.