Flooded Lead Acid Battery Cross Reference
Flooded lead acid batteries share standardized dimensions defined by BCI group numbers. A Group 27 battery from Interstate fits the same tray as a Group 27 from Exide, Motorcraft, or any other brand. The part number on the label is brand-specific, but the physical cell is the same size. This chart covers 77 group numbers across six categories: automotive, commercial, marine/RV, lawn and garden, and golf car, mapping Interstate part numbers to AC Delco, Advance Auto Parts, Auto Zone, East Penn/Deka, O'Reilly, Exide, Motorcraft, and NAPA equivalents.
The group number tells you the physical size and terminal position. Common automotive groups (24, 35, 65, 75, 78) cover most domestic vehicles. Groups 4D and 8D cover heavy commercial trucks and deep-cycle RV banks. Golf car groups GC-2 (6V) and GC-8 (8V) use thicker plates built for repeated deep discharge. When a group shows a letter suffix like 24F, 26R, or 31T, the letter indicates terminal position: the physical battery height and width match the base group, but the positive terminal is in a different location.
PRO TIP: Flooded lead acid batteries require periodic water top-offs. Check electrolyte levels every 30–60 days under regular use. Use only distilled water; tap water introduces minerals that accelerate plate corrosion. If the plates are exposed above the electrolyte line, the battery has likely suffered sulfation damage and may not recover fully. Read our Deep Cycle Maintenance Guide or download the Battery Maintenance Log (PDF) to track your battery's health over time.
Jump to: Automotive • 12-Volt | Commercial • 12-Volt | Commercial • 6-Volt & 8-Volt | Marine/RV • 12-Volt | Lawn & Garden • 12-Volt | Golf Car • 6-Volt & 8-Volt
Automotive • 12-Volt
| Group | Dimensions (L×W×H in) | Volts |
|---|---|---|
| 24 | 10.25 × 6.81 × 8.88 | 12V |
| 24F | 10.88 × 6.81 × 8.88 | 12V |
| 25 | 9.06 × 6.88 × 8.88 | 12V |
| 26 | 8.19 × 6.75 × 7.75 | 12V |
| 26R | 8.19 × 6.75 × 7.75 | 12V |
| 27 | 12.06 × 6.81 × 8.88 | 12V |
| 27F | 12.50 × 6.81 × 8.88 | 12V |
| 34 | 10.25 × 6.81 × 7.88 | 12V |
| 34R | 10.25 × 6.81 × 7.88 | 12V |
| 35 | 9.06 × 6.88 × 8.88 | 12V |
| 36R | 9.00 × 5.06 × 8.88 | 12V |
| 40R | 10.94 × 6.88 × 7.13 | 12V |
| 41 | 11.50 × 6.94 × 6.88 | 12V |
| 42 | 9.56 × 6.94 × 6.88 | 12V |
| 47 (H5) | 9.53 × 7.09 × 7.52 | 12V |
| 48(H6) | 12.09 × 6.89 × 7.52 | 12V |
| 49(H8) | 13.94 × 6.89 × 7.52 | 12V |
| 50 | 8.69 × 6.81 × 8.44 | 12V |
| 51 | 9.38 × 5.06 × 8.81 | 12V |
| 51R | 9.38 × 5.06 × 8.81 | 12V |
| 56 | 10.25 × 6.19 × 7.88 | 12V |
| 58 | 10.94 × 7.19 × 7.75 | 12V |
| 58R | 10.94 × 7.19 × 7.75 | 12V |
| 59 | 9.06 × 6.88 × 8.75 | 12V |
| 65 | 12.06 × 7.56 × 7.56 | 12V |
| 66 | 10.25 × 6.75 × 8.88 | 12V |
| 75 | 9.06 × 7.00 × 7.56 | 12V |
| 75DT | 10.44 × 7.00 × 7.56 | 12V |
| 78 | 10.25 × 7.06 × 7.50 | 12V |
| 78DT | 10.25 × 7.06 × 7.50 | 12V |
| 79 | 15.00 × 7.03 × 9.06 | 12V |
| 85 | 9.00 × 6.75 × 8.13 | 12V |
| 86 | 9.44 × 6.94 × 8.25 | 12V |
| 94R(H7) | 12.40 × 6.89 × 7.52 | 12V |
| 95R(H9) | 13.94 × 6.89 × 7.52 | 12V |
| 96R | 9.50 × 7.00 × 7.56 | 12V |
| 100 | 12.00 × 6.88 × 9.25 | 12V |
| 101 | 11.56 × 7.00 × 7.50 | 12V |
| 121R | 14.88 × 6.88 × 8.50 | 12V |
| 124 | 11.06 × 6.75 × 9.25 | 12V |
| 124R | 11.06 × 6.75 × 9.25 | 12V |
| 151R | 13.94 × 6.89 × 7.52 | 12V |
| T4 | — | 12V |
| T5(90) | — | 12V |
| T6(91) | — | 12V |
| T7(92) | — | 12V |
| T8(93) | — | 12V |
| V4 | — | 12V |
| 46A24L | — | 12V |
Commercial • 12-Volt
Commercial • 6-Volt & 8-Volt
| Group | Dimensions (L×W×H in) | Volts |
|---|---|---|
| 1 | — | 6V |
| 2 | — | 6V |
| 3EH | — | 6V |
| 4 | — | 6V |
| 8V | — | 8V |
Marine/RV • 12-Volt
| Group | Dimensions (L×W×H in) | Volts |
|---|---|---|
| 24DC | 10.25 × 6.81 × 8.88 | 12V |
| 24MS | 10.25 × 6.81 × 8.88 | 12V |
| 27DC | 12.06 × 6.81 × 8.88 | 12V |
| 27MS | 12.06 × 6.81 × 8.88 | 12V |
| 29DC | 13.50 × 6.81 × 9.00 | 12V |
| 31DC | 13.00 × 6.81 × 9.44 | 12V |
| 4DDC | 20.75 × 8.75 × 9.75 | 12V |
Lawn & Garden • 12-Volt
| Group | Dimensions (L×W×H in) | Volts |
|---|---|---|
| 22F | 9.44 × 6.75 × 8.75 | 12V |
| 22NF | 9.44 × 6.75 × 8.75 | 12V |
| 45 | 9.38 × 5.50 × 8.88 | 12V |
| 70 | 8.56 × 6.75 × 8.25 | 12V |
| U1 | 7.75 × 5.19 × 7.25 | 12V |
| U1R | 7.75 × 5.19 × 7.25 | 12V |
Golf Car • 6-Volt & 8-Volt
| Group | Dimensions (L×W×H in) | Volts |
|---|---|---|
| GC-2 | 10.31 × 7.13 × 11.25 | 6V |
| GC-8 | 10.31 × 7.13 × 11.00 | 8V |
How to Read BCI Group Numbers
BCI group numbers are a North American standard that defines a battery's case dimensions and terminal layout, not its electrical output. Two batteries with the same group number will fit the same tray, use the same hold-down bracket, and have terminals in the same location. The voltage, CCA, and amp-hour rating vary by product line within each group.
Letter suffixes change terminal position. The F suffix (24F, 27F) reverses the positive terminal from left to right. The R suffix (26R, 51R, 58R) means the positive terminal is on the right side when facing the battery. The T suffix (31T) indicates threaded stainless steel terminals used in commercial applications. Always match the full group designation including any suffix: a Group 24 and Group 24F are not interchangeable.
European group designations (H5, H6, H7, H8) appear alongside BCI numbers on many vehicles built after 2005. H5 equals BCI Group 47. H6 equals Group 48. H7 equals Group 94R. H8 equals Group 49. If your vehicle manual shows an H-number, use the BCI equivalent in this chart.
What Is an EFB Battery?
EFB stands for Enhanced Flooded Battery. It is a flooded lead acid battery built with a polyester scrim layer bonded to the positive plate. That reinforcement prevents active material from shedding off the plates during repeated charge and discharge cycles, the primary failure mode of conventional flooded batteries in start-stop vehicles. Vehicle electronics have increased 500% over the past 20 years, and over half of new cars sold in the U.S. are now start-stop or hybrid. A standard flooded battery is not built to handle that cycling demand. EFB is.
EFB batteries deliver roughly twice the cycle life of a standard flooded battery, with better dynamic charge acceptance, meaning they recharge faster from regenerative braking pulses. They are physically identical to standard batteries and use the same BCI group numbers, making them a direct drop-in upgrade. OEM adoption is growing as more vehicle manufacturers specify cycling-capable batteries at the factory.
EFB covers a wide range of vehicles. Continental Battery Systems' EFB line covers Groups 24, 24F, 27F, 34, 35, 51R, 65, 78, H5/47, H6/48, H7/94R, and H8/49, fitting Acura, Audi, BMW, Buick, Chevrolet, Chrysler, Dodge, Ford, GMC, Honda, Hyundai, Infiniti, Jeep, Kia, Lexus, Mazda, Mercedes-Benz, Mitsubishi, Nissan, Pontiac, RAM, Subaru, Toyota, Volkswagen, and Volvo, among others.
EFB is also a strong replacement option for vehicles that came with OE AGM. Most vehicles with OE AGM have the battery mounted underhood. In that position, EFB delivers superior heat protection compared to AGM, at a lower price with comparable warranty value. If your vehicle's AGM is mounted in the trunk or under a seat (a sealed compartment), stay with AGM. For underhood AGM replacements, EFB is a legitimate and often better-value alternative.
Flooded, EFB, AGM, and Lithium: What's the Difference?
The four main battery chemistries used in automotive and deep-cycle applications each make different trade-offs between cost, maintenance, cycle life, and performance. The table below covers the key differences so you can match the right technology to your application.
| Feature | Flooded (Standard) | EFB | AGM | Lithium (LiFePO4) |
|---|---|---|---|---|
| Maintenance | Water top-off required every 30–60 days (serviceable vented design) | Usually maintenance-free; many designs are sealed with no routine topping up | Sealed, maintenance-free (no water top-off) | Sealed, maintenance-free under normal use |
| Cycle Life | ~200–400 cycles | ~400–700 cycles (about 2× standard flooded) | ~600–1,000+ cycles, depending on use and quality | ~2,000–5,000 cycles typical BEST |
| Cold Crank Performance | Good starting performance | Good; improved cranking vs. standard flooded | Excellent high-current cranking BETTER | Output reduced at low temps; drops sharply below -10°C |
| Weight | Heaviest (baseline lead-acid) | Heavy (similar to or slightly heavier than flooded) | Heavy (comparable to flooded lead-acid) | 50–70% lighter than equivalent lead-acid BEST |
| Spill-Proof | No — vented liquid electrolyte | No — flooded, not rated spill-proof | Yes — immobilized electrolyte, non-spillable when used correctly | Yes — sealed cells, no free liquid |
| Start-Stop Compatible | No | Yes (mild/basic start-stop systems) | Yes, including start-stop with regenerative braking and high loads BETTER | Yes, where supported by vehicle/BMS integration |
| Deep Cycle Capability | Limited; shallow cycling only (to ~50% DoD) | Moderate cycling tolerance; better than standard flooded, but not a true deep-cycle | Good deep-cycle performance (often usable to ~80% DoD) | Excellent deep-cycle performance (regularly up to ~100% DoD) BEST |
| Temperature Range | Approx. -20°C to 50°C recommended | Approx. -20°C to 50°C (similar to flooded) | Approx. -30°C to 60°C operating range | Approx. -20°C to 60°C; charging restricted below 0°C |
| Relative Cost | $ (Lowest) | $$ | $$$ | $$$$ (Highest upfront cost) |
| Typical Applications | Standard combustion-engine vehicles, basic marine starting, industrial standby | Mild start-stop combustion-engine vehicles, taxis/city cars, entry-level hybrid and 12V aux | OEM start-stop with higher electrical loads, deep-cycle RV, marine, solar storage | High-performance builds, marine trolling, solar storage, weight-critical installs |
Flooded vs. AGM: Choosing the Right One
Flooded lead acid batteries are the standard choice for most automotive, marine, and commercial applications where the battery stays upright, ventilation is available, and the owner is willing to check electrolyte levels. They cost less than AGM and accept a wider range of charger types.
AGM (absorbed glass mat) batteries are sealed, spill-proof, and maintenance-free. They are required in some start-stop vehicles and preferred for applications where the battery may be mounted on its side or in a sealed compartment. Most vehicles that came from the factory with flooded batteries can accept an AGM replacement in the same group size, but vehicles with OEM AGM should stay with AGM, since their charging systems run at higher voltages that can overcharge a flooded battery.
Frequently Asked Questions
What is a BCI group number?
BCI (Battery Council International) group numbers define a battery's physical dimensions, terminal placement, and terminal type. A Group 24 battery from any brand will fit the same tray as any other Group 24 battery. The group number does not specify voltage, capacity, or CCA; those vary by product line within each group.
Can I use an Exide battery in place of an Interstate?
Yes, as long as both are the same BCI group number. The group number guarantees physical compatibility: same length, width, height, and terminal placement. Look up your current battery's group number, then find the matching Exide part number in this chart.
What is the difference between a Group 24 and a Group 24F battery?
Both are 12V batteries, but the 24F is slightly longer (10.88 in vs. 10.25 in) and has reversed terminal polarity compared to the standard Group 24. The 24F is common in many Asian vehicles like Honda, Toyota, and Nissan. A Group 24 and 24F are not interchangeable. Always match the letter suffix exactly.
What is an EFB battery and when do I need one?
EFB (Enhanced Flooded Battery) is a modified flooded battery with a reinforced positive plate that handles repeated charge/discharge cycles better than standard flooded. You need one if your vehicle has a mild start-stop system that shuts the engine off at traffic lights. Using a standard flooded battery in a start-stop vehicle will shorten its life significantly. If your vehicle came with an EFB, replace it with an EFB or upgrade to AGM, do not downgrade to standard flooded.
What do 4D and 8D mean on a commercial battery?
Group 4D and 8D are large-format commercial 12V batteries. The 4D measures 20.75 × 8.75 × 9.75 inches and typically delivers 150–200 Ah. The 8D is wider at 20.75 × 11.00 × 9.75 inches with 225–260 Ah capacity. Both are used in semi-trucks, RVs, solar storage, and marine applications requiring high reserve capacity.
What is a GC-2 golf car battery?
GC-2 (golf car 2) is a 6-volt deep-cycle flooded battery measuring approximately 10.31 × 7.13 × 11.25 inches. Golf carts typically use four GC-2 batteries in series for 24V, or six for 36V. The GC-8 is an 8-volt variant used in 48V systems with six batteries in series.
How often do flooded lead acid batteries need water?
Check electrolyte levels every 30 to 60 days under regular use. Add only distilled water, never tap water, which introduces minerals that corrode the plates. Fill to just above the plates but not to the vent tube. Overfilling causes acid to overflow during charging. Batteries under heavy cycling need more frequent checks. See the watering section of our Deep Cycle Maintenance Guide for step-by-step instructions.
What is the difference between a Marine/RV battery and an automotive battery?
Marine/RV batteries are designed for deep-cycle use: they can discharge to 50% or lower repeatedly without damage. Automotive starting batteries deliver a large burst of current to start an engine but are not designed for sustained discharge. Group 24DC, 27DC, and 31DC batteries share physical dimensions with their automotive counterparts but use thicker plates built for cycling.
What U1 battery fits my lawn mower?
Most riding mowers and lawn tractors use a Group U1 battery (7.75 × 5.19 × 7.25 inches, 12V). The U1 has the positive terminal on the left; the U1R has the positive terminal on the right. Check which terminal faces forward in your mower's battery compartment before ordering. Interstate's SP-18, SP-30, and SP-35 are common U1 choices for residential mowers.
How do I read a battery manufacturer date code?
There is no single standard; it depends on the brand. Interstate, Exide, Deka, and others each use different formats, ranging from alphanumeric stamps to heat-shrink labels to laser-etched codes. Some encode the year and month as a letter-number pair (A1 = January 2021), others use a Julian date, and some stamp a plain month/year. See our comprehensive guide to reading battery manufacturer date codes for a brand-by-brand breakdown with examples.
Disclaimer
Trademarks & Brand Names: All battery manufacturer names, logos, trademarks, and brand names mentioned on this page—including but not limited to Interstate Batteries, AC Delco, Advance Auto Parts, AutoZone, East Penn/Deka, O'Reilly Auto Parts, Exide Technologies, Motorcraft, NAPA, and Continental Battery Systems—are the property of their respective owners. Batteries in a Flash is not affiliated with, endorsed by, or sponsored by any of these manufacturers. This page is provided for informational and educational purposes only.
Accuracy & Updates: While we strive to provide accurate and up-to-date cross-reference data, manufacturers may change part numbers, discontinue product lines, or revise group number specifications without notice. Cross-reference matches guarantee physical compatibility based on BCI group number; CCA, reserve capacity, and warranty terms vary by brand and product line. Verify fitment with your battery retailer before purchasing.
Found an Error? If you notice any inaccuracies, outdated part numbers, or missing equivalents, please let us know. Visit our contact page to report errors or suggest improvements. We regularly update this chart to keep it current.