The Group 51 12-volt battery is incredibly popular. People everywhere use it as both a starting and deep-cycle car battery for their vehicles, boats, RVs — you name it!
Whether in commercial trucks, construction rigs, or farming gear, this amazing power source will start with gusto each and every time. With features such as general-purpose reliability and auxiliary support capabilities, this battery group is commonly used in a wide variety of applications.
Group 51 vs 51R – What is the difference?
Battery types can sometimes get confusing, so here’s a helpful tip! For the 51R battery, its positive terminal is located on the right and its negative side is to the left; this is flip-flopped from how most batteries go.
While usually the positive side’s situated on the left and ground power is just within easy reach on the opposing side!
Group 51 and 51R Battery Features
The 51 and 51R groups boast impressive characteristics for starting power, deep-cycling capability, and reliability. Strong straps join thick grids, which in turn are coupled with generous plates; the combined craftsmanship renders superior endurance even under demanding circumstances!
Dimension
Terminal positions
Weight
This piece of power easily clocked in between 25 and 45 lbs, so transport shouldn’t be too much of an issue either!
RC Rating
The RC rating indicates the capacity (from 45 to 135 minutes) it offers. That means up to two hours of idle power before cutting out!
CCA Range
The rating of the CCA (Cold Cranking Amps) measures how much current the battery can provide at 0°F (-18°C). The CCA rating for a group 51 battery is between 300 and 500, a good number considering the battery’s size.
Best Group 51 Battery Models
ACDelco Gold B24R (51 dual purpose/AGM)
The ACDelco B24R is a dual-purpose battery for starting and deep cycle purposes. It is made with a calcium alloy to allow it to offer a fine-grain, corrosion-resistant grid. It has a rigid construction that protects it from road vibrations. It required an upright storage position at moderate temperatures to prevent self-discharge.
The battery provides high cranking amps and reserve capacity. It also has a low self-discharge rate, meaning it will hold its charge longer than other battery types. This makes it an ideal choice for seasonal or infrequent use vehicles.
Features Highlights:
- Spill & leak-resistance.
- 100% Maintenance-Free.
- Vibration resistance.
- High corrosion-resistance.
- CCA: 325 Amps.
- Nominal capacity: 45Ah.
- Reserve Capacity (RC): 70 minutes.
- Weight: 29 pounds.
Optima Batteries OPT8071-167 D51 (51 dual purpose/AGM)
Are you in the market for a high-performance Group 51 battery? Look no further than Optima 8071! Engineered with an innovative and highly efficient plate design, this advanced dual-purpose AGM battery can deliver exceptional power output and increased longevity even when subjected to extreme temperatures or vibrations.
Perfect for loaded vehicles such as trucks with winches or sound systems, its extensive warranty provides extra peace of mind too – it’s hard to beat this superb choice from Optima batteries!
Features Highlights:
- SpiralCell Technology.
- Deep-cycle and cranking power.
- Extended maintenance-free life.
- Vibration resistant.
- Spillproof.
- CCA: 450 Amps.
- Nominal capacity: 38 Ah.
- Reserve Capacity (RC): 66 minutes.
- Weight: 26 pounds.
XS Power D5100R XS Series (51R dual purpose/AGM)
The XS Power D5100R XS Series battery has caught the attention of car audio fanatics due to its formidable performance and long-lasting endurance.
Made with absorption glass mat technology that traps electrolytes in a fiberglass hold, it’s both spill-proof and shockproof. Plus, this rugged, sealed powerhouse is also considered vibration resilient! Perfect for any auto rigs upgraded from their factory systems using extra amps or woofers, plus RV’s too can take advantage by leveraging off this 51 group cellular blaster dynamo efficiently catering to even higher powered demands than others on the market today.
Features Highlights:
- Absorbed Glass Mat.
- Vibration resistant.
- Ultra-low internal resistance.
- It can be mounted in almost any position.
- MCA: 745 Amps.
- Nominal capacity: 60 Ah.
- Reserve Capacity (RC): 100 minutes.
- Weight: 39.6 pounds.
Group 51 Battery Equivalents
The Group 51 battery is a high-performance battery often used in standard and popular Japanese vehicles. Sometimes they are hard to come by. Here are two equivalents that you can use with your car.
The Group 51R
Group 51R: This versatile dual-purpose battery provides top performance for both starting and deep cycling applications! Same size as Group 51, making it a great replacement option. But remember to take note of the different polarities when you switch them out! An excellent way to meet your power needs.
The Group U1
Group U1 packs plenty of punch! With comparable cranking amps and reserve capacity as compared to a traditional Group 51, plus its small form factor, it is ideal for power-hungry rides.
Of course, before switching out your trusty battery with something new, be sure to consult your car’s owner’s manual so you can avoid any unpleasant surprises in the future!
FAQs
Can I use 51R instead of 51?
Yes, you can use a 51R instead of a 51 battery. Since the dimensions of the 51R battery and the group 51 battery are the same, you can simply flip the 51R battery around and use it as a group 51 battery.
What does a Group 51 battery fit?
A group 51 battery is a high-performance battery often used in standard and popular Japanese vehicles. It is also used in North American vehicles, boats, and RVs.
What does the R mean on a battery?
The R shows the polarity change in Group 51R, in which instead of having its positive terminal on the left like Group 51, it has its positive terminal on the right.
Is 51R battery AGM?
How many Ah is a 51R car battery?
The 51R car battery has an Ah rating of 38-60.
What does battery group size 65 mean?
Group 65 batteries are AGM sealed lead acid batteries. They are often used in cars, boats, and for industrial applications. They are mid-size batteries that are often made as dual-purpose AGM batteries, so they can be used for both starting and deep cycle purposes. You can check our guide about group 65 batteries for more insights.
Conclusion
Before you switch, make sure to check the owner’s manual of your vehicle since Group 51 and 51R batteries have similar looks but are different in polarity. Commonly used on small vehicles and boats, these powerful dual-purpose pieces can both start up engines and serve deep cycling needs!
James is an engineer and a professional blogger. He has gained extensive experience over the years, handling all types of power projects. He loves to share his experiences with all things related to batteries, generators, and other power-related topics.
