It’s hard to differentiate the Kubota tractor battery size, and sometimes it’s even annoying and frustrating. To help you out, we made this article.
In which we will specifically introduce the 4 main batteries BCI Group Size 51R, 24 / 24F, 27 / 27F, and 31 for Kubota tractors, and you can get a quick buying guide whether you have a Kubota B, L, or MX series, and more.
Why the Right Battery Size Matters
Using the wrong battery size leads to starting issues, premature failure, and potential damage to your tractor’s electrical system. Matching the correct size ensures reliability and protects your investment.
Understanding Key Battery Specifications
- BCI Group Size: The most important factor. It defines the battery’s physical dimensions and terminal placement for a perfect fit.
- Voltage: Kubota tractors use a standard 12-volt system.
- Cold Cranking Amps (CCA): A battery’s ability to start in the cold. Higher is better for colder climates.
- Reserve Capacity (RC): How long the battery can run the tractor if the alternator fails.
The Kubota Tractor Battery Size Chart
This chart details the most common BCI Group Sizes for Kubota’s main tractor series. If you don’t find what you need, feel free to contact our expert team.
BCI Group Size 51R
A small, compact battery known for its small footprint and top-post terminals. The “R” for “Reversed” is critical, indicating the positive terminal is on the right, matching the tractor’s cable layout.
- Primary Use: Kubota BX Series: BX1880, BX2380, BX2680, BX23S, etc.
- Why it fits: The compact frame of the BX Series leaves no room for a larger battery. The Group 51R provides the necessary CCA for its small diesel engine while fitting perfectly into the limited space.


BCI Group Size 24 / 24F
A “workhorse” battery offering a significant power step-up. It’s one of the most common sizes available. The “F” also indicates a reversed terminal layout.
- Primary Use: Kubota B and L Series: B2301, B2601, L2501, L3302, L3902, etc.
- Why it fits: These versatile tractors need a reliable power source for their medium-sized engines and hydraulics. The Group 24/24F fits their standard battery trays and delivers strong, all-weather starting power.
- Secondary Use: Kubota MX Series: MX5400, MX6000, etc.
- Why it fits: Many MX models are designed to use the powerful and widely available Group 24F, which provides ample power for their robust engines without needing an oversized battery compartment.
BCI Group Size 27 / 27F
Dimensionally similar to the Group 24 but slightly longer, allowing for more internal plates. This translates to higher CCA and Reserve Capacity for more demanding applications.
- Primary Use: Larger Kubota L and MX Series Models: L4701, L6060, and select higher-horsepower MX models, etc.
- Why it fits: Models with larger engines, enclosed cabs (with HVAC), or advanced electronics create a higher electrical load. The Group 27 ensures reliable starting and provides the extra reserve capacity needed to power these systems.


BCI Group Size 31
A heavy-duty commercial battery, easily identified by its large size, heavy weight, and stud terminals. These threaded studs provide a vibration-proof, high-amperage connection required for heavy machinery.
- Primary Use: Kubota M Series: M4-071, M5-111, M6-141, M7-172
- Why it fits: The massive, high-torque engines in these farm tractors require immense power to turn over. The Group 31 battery delivers the huge CCA needed, and its stud terminals can handle the high current and constant vibration of fieldwork.
- Secondary Use: Kubota Construction Equipment: SVL75, SVL97, KX080, U55, etc.
- Why it fits: Like the M Series, heavy construction equipment runs powerful engines and demanding hydraulics. The Group 31 provides the extreme durability and starting power required for professional job sites where reliability is non-negotiable.
Quick-Select Kubota Tractor Battery Size Chart
Use this table to quickly identify the correct battery group size based on your tractor’s series.
| Battery BCI Group Size | Tractor Type | Common Kubota Series |
|---|---|---|
| Group 51R | Sub-Compact Tractors | BX Series |
| Group 24 / 24F | Compact & Utility Tractors |
|
| Group 27 / 27F | High-Power Compact Tractors | Larger L & MX Series |
| Group 31 | Large Ag & Construction |
|
How to Find the Correct Battery
- Check Your Manual: It lists the exact BCI Group Size and CCA.
- Inspect the Old Battery: The label shows the Group Size (e.g., “24F”).
- Match Dimensions & Terminals: Ensure the new battery fits and the +/- posts align.
Essential Maintenance Tips
- Keep Terminals Clean: Prevents corrosion and ensures a good connection.
- Check Charge Regularly: Use a multimeter to ensure it’s around 12.6 volts.
- Inspect for Damage: Look for cracks or leaks and replace if damaged.
- Store Properly: During the off-season, use a battery maintainer.
A Note on Lithium Batteries
Lithium batteries are lighter and last longer, but you must ensure they are fully compatible with your tractor’s electrical system. When in doubt, consult your dealer before switching.
Final Thoughts:
For your Kubota tractor’s power and efficiency, you need to choose the right battery. Follow this guide, choose the battery of the perfect size, and maintain your model and its battery regularly, so that your equipment can run strong and healthy.
Remember to always refer to the owner’s manual and buy the right battery & battery chargers from reliable suppliers like FridayParts for your Kubota Tractor. Visit our one-stop online shop today to explore the full battery catalog!
