What is the Difference Between a Group 24 and a Group 35 Battery?

Group 24 and Group 35 batteries differ in size, power output, and applications. Group 24 batteries are larger (10.25″ x 6.8″ x 8.9″) and offer 70-85 Ah capacity, ideal for standard vehicles. Group 35 batteries are smaller (9.06″ x 6.88″ x 8.43″) but provide higher cold cranking amps (550-650 CCA) and 60-80 Ah capacity, commonly used in trucks, marine, and high-demand systems.

What Is a Group Size 24 Battery?

How Do Group 24 and Group 35 Batteries Compare in Size?

Group 24 batteries measure 10.25″ (L) x 6.8″ (W) x 8.9″ (H), while Group 35 batteries are slightly shorter at 9.06″ (L) x 6.88″ (W) x 8.43″ (H). The reduced size of Group 35 allows easier installation in compact engine compartments, though both share similar terminal placements (top-post design) for compatibility with most vehicles.

Dimension	Group 24	Group 35
Length	10.25″	9.06″
Width	6.8″	6.88″
Height	8.9″	8.43″

Which Battery Offers Higher Cold Cranking Amps?

Group 35 batteries typically deliver 550-650 CCA, outperforming Group 24 batteries (400-500 CCA). This makes Group 35 better suited for cold climates or diesel engines requiring robust starting power. For example, Optima’s Group 35 RedTop provides 720 CCA, while a standard Group 24 battery like the DieHard Gold offers 500 CCA.

What Are the Primary Applications for Each Battery Type?

Group 24 batteries power standard vehicles (sedans, small SUVs) and basic marine electronics. Group 35 batteries are preferred for trucks, RVs, and boats with dual-battery setups or advanced accessories (winches, inverters). Interstate Batteries’ Group 35M-EFB is engineered for start-stop technology in modern cars, enhancing fuel efficiency.

In commercial fleets, Group 35’s compact size proves advantageous for vehicles with limited engine bay space, such as delivery vans and hybrid trucks. Its vibration-resistant design also makes it a favorite for off-road enthusiasts using lifted Jeeps or ATVs. Meanwhile, Group 24 remains the go-to choice for backup power systems in stationary applications like solar farms or emergency lighting due to its higher reserve capacity. Marine technicians often recommend Group 24 for trolling motors on fishing boats, where sustained runtime outweighs the need for compact sizing.

Can You Replace a Group 24 Battery with a Group 35?

Yes, if the battery tray and hold-down bracket accommodate Group 35’s smaller size. Ensure terminals align and CCA meets OEM requirements. For instance, replacing a Group 24 (500 CCA) with a Group 35 (650 CCA) in a Honda Accord improves cold starts without modifications. Always verify clearance and voltage compatibility (both are 12V).

What Are the Cost and Lifespan Differences?

Group 24 batteries cost $100-$150 and last 3-5 years. Group 35 batteries range from $120-$200 but offer extended lifespans (4-6 years) due to advanced AGM or EFB designs. For example, a Deka Intimidator Group 35 AGM costs $180 but includes a 7-year warranty, outperforming budget Group 24 lead-acid models.

How Does Reserve Capacity Impact Performance?

Group 24 batteries average 120-140 minutes reserve capacity (RC), while Group 35 ranges from 90-130 minutes RC. Lower RC in Group 35 is offset by higher CCA, prioritizing starting power over sustained energy delivery. Marine applications favoring RC may still prefer Group 24, like the VMAX XTR24-90 with 180-minute RC.

Reserve capacity becomes critical in scenarios where alternators fail or auxiliary loads spike. For RV owners running refrigerators and inverters during camping trips, Group 24’s extended RC provides buffer time before recharge. Conversely, Group 35’s shorter RC isn’t a drawback in daily commuter cars where alternators promptly recharge batteries. Recent advancements like carbon-enhanced Group 35 batteries now bridge this gap—NorthStar’s NSB-AGM35 boasts 135-minute RC alongside 710 CCA, making it viable for both engine starts and moderate accessory loads.

Which Battery Is Better for Off-Grid Power Systems?

Group 35 AGM batteries excel in off-grid setups due to vibration resistance and deep-cycle capabilities. The Renogy Group 35 AGM supports 500+ cycles at 50% depth of discharge, ideal for solar storage. Group 24 flooded batteries are cheaper but less durable for frequent cycling, making them better for backup power in RVs.

Expert Views

“Group 35 batteries dominate the aftermarket due to their balance of size and power. We’re seeing a 30% annual sales increase as automakers adopt smaller engine bays,” says John Harris, lead engineer at BatteryTech Solutions. “AGM variants now account for 60% of Group 35 sales, reflecting demand for maintenance-free reliability in extreme conditions.”

Conclusion

Choosing between Group 24 and Group 35 hinges on vehicle requirements and climate. Group 24 suits standard applications with budget constraints, while Group 35 delivers superior power for demanding environments. Always cross-check dimensions, CCA, and reserve capacity against OEM specifications before purchasing.

FAQs

Are Group 24 and Group 35 Batteries Interchangeable?

Yes, if physical dimensions and terminal positions align. Verify CCA meets or exceeds OEM requirements for reliable performance.

Which Battery Lasts Longer: Group 24 or 35?

Group 35 AGM batteries typically outlast Group 24 by 1-2 years due to advanced construction and lower sulfation rates.

Can I Use a Group 35 Battery in a Boat?

Yes, Group 35 is popular for marine use. Ensure it’s rated for marine applications (e.g., dual-purpose starting/deep-cycle) to handle vibration and humidity.