51 Vs 51r battery – What Is The Difference?

The main difference between the 51 and 51R battery is that the 51 has the battery post on the left. While the 51R battery post is on the right.

The world of car batteries is a daunting one to navigate. We have all experienced the frustration of needing our battery and being unable to find one at one local auto parts store. You might think that you only need to replace your dead battery with a similar one, but it turns out that this is quite complicated at times. From size, type, location on the vehicle, and even brand, there are so many things to consider when buying a new car battery.

In addition, batteries are categorized by their groups. A couple of examples are Group 51 and 52R batteries. What is the difference between a 51 and 51R battery? These two are often confused with each other because they have similar dimensions and features. However, there are some significant differences that need to be discussed before deciding which battery to purchase.

Continue reading to understand better what these two different types of car batteries are and know the difference from each other, as well as some recommendations based on your driving habits.

Difference between 51R and 51 battery: Dimensions, Features, and Recommendations

For many years, these BCI Group 52 and 51R starting and dual-purpose batteries have been the most popular battery for automotive applications. But now, they are being used for more general purposes due to their stable power sources. However, what are the difference between 51 and 51r battery?

Since the size of the BCI Groups 51 and 51R batteries varies a little bit, it is best and important to measure your battery compartment before ordering any model. For example, some manufacturers optimize their models for specific applications in order to make them slightly smaller or even larger than other models from different companies, which might be more adjustable. So you’ll need one that fits perfectly.

The BCI Group 51 dimensions and the BCI Group 51R batteries are both designed to fit into a standard 9.374 x 5.0625 x 8.8125 inch (23.8 x 12.9x 22 3 cm) rectangular box. This unique feature is perfect for large and older vehicles.

One of the most outstanding features of Groups 51 and 51R batteries is their vibration resistance. This will ensure that the battery will stay in its place while driving and even during an unexpectedly bumpy ride, which is also excellent for those who live an active lifestyle or drive off-road often.

For a more suitable fit, some batteries are designed to be smaller and lighter. One good example is Group U1, labeled as Group 51 battery with a decreased weight and capacity. These specially built batteries are a much better option for the intended application because they’re optimized and can be made with specific needs in mind.

Here are some of the most popular and reliable options for Group 51 and 51R batteries.

For AGM Dual Purpose Batteries:

ACDelco ACDB24R – with 45Ah, 325CCA, 390MCA and 29.11lbs; 13.2kg in weight.

Delphi BU9051P MaxStart – with 46Ah, 325CCA, 390MCA and 29.5lbs; 13.4kg in weight.

Optima 8071-167 D51 – with 38Ah, 450CCA, 575MCA and 26lbs; 11.8kg weight.

Optima 8073-167 D51R – with 38Ah, 450CCA, 575MCA and 26lbs; 11.8kg weight.

XS Power D5100 XS and  XS Power D5100R XS – both with 60Ah, CCA Not Applicable, 745MCA, and 39.6lbs; 18.0kg weight.

For AGM Starting Batteries:

Deka/East Penn 8AMU1R – with Ah Not Applicable, 320CCA, 400MCA, and 25lbs; 11.3kg weight.

For AGM Deep Cycle Batteries:

VMAXTANKS SLR60 – with 60Ah, CCA Not Applicable, MCA Not Applicable, and 43lbs; 19.5kg weight.

ACDelco ACDB24R Battery

The ACDelco ACDB24R Group 51 battery is the best in its class, balancing weight and power. It’s used by many people as an automotive alternative because of this balance, but it can also be found powering up a wide variety of other devices too.

This battery has a durable design to withstand vibrations and impacts, which is perfect for off-road enthusiasts.

The best way to store ACDelco ACDB24R battery is in an upright position with a temperature between 32°F and 70°F to avoid any mishaps or leaks due to a very slow chemical reaction taking place. When stored for prolonged periods of time, discharge can also occur, leading to undesirable odors within the terminal posts on both sides of each cell. The more you store your battery, the greater chance it will leak and have an unpleasant odor.

Delphi BU9051P MaxStart Battery

Delphi BU9051P is an automotive battery that can also be used for other purposes. It’s not as popular as ACDelco batteries, but it has a reputation of being just about the best you’ll find in its price range.

This battery has 20x the vibration resistance of conventional batteries. It is perfectly built for today’s electronics needs. Extended cold-cranking amps delivery means more power to get you through those long workdays and late-night performances without a hitch. Engineered to withstand harsh conditions with its sealed housing and manifold venting system, the stainless steel exhaust is made for your vehicle.

Optima 8071-167 D51 and Optima 8073-167 D51R Batteries

Optima 8071-167 D51 and Optima 8073-167 D51R YellowTop are ideal batteries for your car. These batteries can be used in various situations, including starting engines or providing emergency power to other electronic devices such as radios, GPS navigation systems, and cell phones during emergencies. With these features combined with the highest quality standards at an affordable price point, you get what is believe one of the best deals on premium dual-purpose group 51/D51R yellow top automotive batteries available today.

Batteries that are charged with a smart charger will prevent overcharging and damage to the vehicle’s battery. This is especially important for AGM batteries. Make sure you use the correct type of charging device.

Optima batteries will never let you down, even when the weather is terrible. These have a 66-minute reserve capacity, so they can operate continuously for as long as you need without stopping or slowing down on account of the cold air and moisture that would otherwise adversely affect other batteries’ performance.

XS Power D5100 XS and XS Power D5100R XS Batteries

XS Power D5100 and XS Power D5100R are dual-purpose batteries that belong to groups 51 and 51R. They are not as prominent in size, but they have the exact dimensions of 9.04 x 5.43 x 8.19 inches which places them right next to Group 22NFs on battery compatibility.

XS Power D5100 and XS power D5100R can be used in automobiles or other equipment. These Group 51/51R (or 22NF) batteries may just become the best you have ever bought.

With a price that can be seen as fair, XS Power D5100 and XS Power D5100R are very popular batteries for use in group 51/51R.

These batteries are designed to last for years and withstand harsh environments, making them the perfect choice for those looking to get a battery that is reliable. XS Power batteries are an environmentally-friendly that is spillproof, sealed, and vibration resistant. This means it can mount to any position while also being ultra-low in internal resistance.

Deka/East Penn 8AMU1R Battery

East Penn 8AMU1R AGM is a sealed AGM (Absorbed Glass Mat) battery starter or cranking power source that will work great in your car, boat, or RV. This battery has a 45 reserve capacity with 7.75 x 5.15 x 7.25 inches in dimension.


VMAXTANKS SLR60 is a deep cycle battery with a physical dimension of 9.2 x 5.5 x 8.2 – basically, it belongs to the 22NF group but is labeled a group 51 battery.

VMAXTANKS SLR60 is not a great starting battery, but because it can provide a large number of charging and discharging cycles and accommodate cycling applications such as off-the-grid solar power systems or kayak trolling motors, VMAXTANKS SLR60 offers an excellent option for these types of projects.

This battery has a life span of about 8 to 10 years and offers 99% recombination capabilities which means they do not emit fumes or gases.

Frequently Asked Questions

What is the difference between group 51/51R and 22NF batteries?

The main differences are physical dimensions, reserve capacity, vibrations resistance, spillproof properties, and internal battery design that affects both charging efficiency and how long your battery can hold a charge when not in use. 51 battery size is standard, while 51R is a little larger. The main difference between the two is the capacity and cold cranking amps.

What is the best AGM battery available in store?

AGM batteries have many advantages over other batteries. Be sure to check if they do not leak fluids or gases and are more efficient at retaining power when the vehicle is not running than other types of batteries.

How to prolong the life of a battery?

By keeping it clean and well maintained, you can prolong the life of batteries. You may also check with an expert for tips and tricks on how to preserve your battery.

What is a good practice for storing deep cycle batteries?

It is important to store all types of batteries in cool conditions with minimal exposure to heat as prolonged high temperatures will lead to faster degradation.

Remember that Group 51 and 51R batteries are a dual-purpose type designed for automotive, solar, and other applications. When choosing the best battery for your need, consider what will be powered by the battery and select from among the best group 51 and group 51R batteries available.

When you need a battery for your device, it is vital to know the dimensions and features of each type. We hope this article served you enough information about these two types of batteries to make an informed purchase decision based on what is most suitable for your needs.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.