Are group 24 and 35 batteries the same?

No, Group 24 and Group 35 batteries are not identical. While both are lead-acid batteries used in automotive and marine applications, Group 24 batteries are larger (10.25″ x 6.8″ x 8.9″) and offer higher capacity (70-85 Ah), whereas Group 35 batteries are more compact (9.06″ x 6.88″ x 8.43″) with slightly lower capacity (45-65 Ah). Compatibility depends on vehicle design and power requirements.

What Is a Group Size 24 Battery?

What Are the Physical Differences Between Group 24 and 35 Batteries?

Group 24 batteries are bulkier, weighing 40-50 lbs, while Group 35 batteries weigh 30-40 lbs. The 1.2-inch height difference and terminal placement variations make them incompatible for direct swaps in most vehicles. For example, Honda Civics often use Group 35, while larger trucks may require Group 24 for extended cranking power.

Feature	Group 24	Group 35
Length	10.25 inches	9.06 inches
Weight Range	40-50 lbs	30-40 lbs
Terminal Type	Top-post	Side-post (common)

Installation challenges arise from these variations. Mechanics often use adapter kits for terminal conversions, but this introduces resistance points that can affect electrical efficiency. The width difference (6.8″ vs. 6.88″) seems negligible but becomes critical in battery trays with tight tolerances, such as those in modern electric vehicles where space optimization is paramount.

How Do Performance Metrics Compare Between These Battery Groups?

Group 24 batteries deliver 700-800 cold cranking amps (CCA), ideal for diesel engines or cold climates. Group 35 provides 500-650 CCA, suited for compact gasoline engines. A Group 24’s reserve capacity (120-140 minutes) outperforms Group 35’s 90-110 minutes, making it better for accessory-heavy setups like RVs or boats with trolling motors.

The performance gap widens under load stress. In dual-battery setups for overlanding vehicles, Group 24 maintains stable voltage output when powering winches and refrigerators simultaneously, whereas Group 35 may require frequent recharging cycles. Advanced AGM (Absorbed Glass Mat) variants of Group 24 achieve 20% faster recharge rates compared to standard flooded models, while Group 35 AGM batteries focus more on vibration resistance for urban driving conditions.

Which Vehicles Typically Use Group 24 vs. Group 35 Batteries?

Group 24 powers heavy-duty applications: Ford F-250s, marine deep-cycle systems, and commercial equipment. Group 35 fits mainstream sedans (Toyota Camry, Hyundai Sonata) and hybrids where space efficiency matters. Using the wrong group risks poor fitment, terminal corrosion, or insufficient voltage during engine startup.

Vehicle Type	Common Battery Group	Power Demands
Full-size Trucks	Group 24	High CCA for towing
Compact EVs	Group 35	Auxiliary systems only
Fishing Boats	Group 24	Deep-cycle requirements

Emerging vehicle trends impact battery selection. Start-stop technology in modern hybrids favors Group 35’s rapid recharge capability, while off-road modifications often necessitate upgrading to Group 24. Marine applications demonstrate this divide clearly—pontoon boats with minimal electronics use Group 35, but sailboats with navigation systems and inverters require Group 24’s endurance.

Can You Substitute Group 24 for Group 35 (or Vice Versa)?

Substitution requires verifying tray dimensions, terminal orientation (SAE vs. JIS standards), and electrical load. Adapting a Group 24 into a Group 35 slot may demand bracket modifications, risking warranty voidance. Case study: A 2020 Subaru Outback’s battery compartment lacks clearance for Group 24’s height, causing hood contact hazards.

What Are the Cost and Lifespan Variations?

Group 24 batteries cost $150-$220 due to robust construction, lasting 4-6 years with proper maintenance. Group 35 ranges from $100-$160, averaging 3-5 years. Budget-conscious drivers with low power demands may prefer Group 35, while off-grid enthusiasts benefit from Group 24’s longevity in deep-cycle applications.

How Does Temperature Tolerance Differ Between These Groups?

Group 24’s thicker plates withstand -40°F to 140°F extremes better, suffering only 15% capacity loss at 0°F versus Group 35’s 25% loss. Arctic-region users report Group 24’s superior performance in diesel trucks, whereas Group 35 struggles in prolonged subzero starts without external heating aids.

Are There Maintenance Practices Unique to Each Battery Group?

Group 24’s vent caps require monthly electrolyte level checks in flooded variants, while Group 35’s sealed AGM designs are maintenance-free. Overcharging Group 24 beyond 14.8V accelerates plate sulfation, whereas Group 35’s absorbed glass mat technology tolerates minor voltage spikes better.

“Selecting between Group 24 and 35 isn’t just about size—it’s a systems engineering decision,” says Dr. Elena Torres, automotive battery researcher. “Group 35’s optimized power-to-weight ratio suits start-stop hybrids, but Group 24’s deep-cycle resilience is irreplaceable in marine applications. Always cross-reference OEM specs with your usage patterns.”

Conclusion

Group 24 and 35 batteries serve distinct purposes despite superficial similarities. Vehicle compatibility, performance needs, and environmental factors dictate the optimal choice. While substitution is technically possible with modifications, adhering to manufacturer guidelines ensures safety and longevity.

FAQ

Q: Can I upgrade my sedan from Group 35 to Group 24 for more power?

A: Not recommended—physical incompatibility and excessive weight may strain charging systems.

Q: Do lithium-ion variants exist for these groups?

A: Yes, but they’re 2-3x pricier. Lithium Group 35 batteries weigh 50% less than lead-acid versions.

Q: How do I decode battery group numbers?

A: The Battery Council International (BCI) assigns numbers based on dimensions, terminal placement, and polarity—not performance metrics.