2015 Ram 2500 Battery Size, Group & Replacement Guide

Quick answer: 2015 Ram 2500 Battery Specs

• BCI Group Size: H7 (also called 94R)
• Cold Cranking Amps (CCA): 800 CCA
• Reserve Capacity (RC): 140 minutes
• Battery Type: AGM (Absorbent Glass Mat) required
• Terminal Layout: Top-post, right-side positive
• Physical Dimensions (approximate): 12.4" L x 6.9" W x 7.5" H
• Diesel Engine Setup: Dual-battery system (two H7/94R batteries)

Replacement battery options

• Interstate: MTX-94R/H7
• DieHard: Platinum AGM H7-AGM
• Odyssey: 94R-850
• ACDelco: 94RAGM
• Optima: DH7

AGM vs flooded — which does this vehicle need?

The 2015 Ram 2500, across all engine options, requires an Absorbent Glass Mat (AGM) battery from the factory. This is not an optional upgrade. The vehicle's charging system and electrical demands are specifically calibrated for the charge/discharge characteristics of an AGM battery. Using a standard flooded lead-acid battery can lead to a shorter service life, electrical system faults, and potential damage to the charging system. AGM batteries are better suited to handle the high accessory loads and start-stop functionality (if equipped) common in modern trucks.

Post-installation relearn / reset procedure

Unlike many other vehicles, the 2015 Ram 2500 typically does not require a complex, scan-tool-based battery relearn procedure. The Engine Control Module (ECM) will adapt to the new battery's state of charge and capacity over time. However, to ensure a smooth transition:

1. Maintain Power: Use a memory saver tool that plugs into the OBD-II port to maintain power to the vehicle's computers during the battery swap. This will prevent the loss of radio presets, trip computer data, and learned shift points.
2. Reset Tip-in: If you do disconnect power completely, the throttle body's learned position may be lost, leading to a rough idle temporarily. To correct this, you can perform a throttle pedal reset: Turn the ignition to the "On" position (without starting the engine), slowly press the accelerator pedal all the way to the floor, slowly release it, and then turn the ignition off. The next time you start the truck, the idle should be stable.

Signs of a failing battery

• Slow Engine Crank: The most obvious sign. The engine turns over sluggishly, especially on cold mornings.
• "Check Battery" or "Battery Voltage Low" Warning: A message may appear on the instrument cluster.
• Dimming Lights: Headlights or interior lights may flicker or dim, especially at idle or when using accessories like the power windows.
• Swollen Battery Case: If the battery case looks bloated or warped, it's a sign of internal failure and must be replaced immediately.
• Corrosion on Terminals: White, blue, or greenish powder around the battery posts indicates leaking acid and a poor connection.

Common battery issues for this generation

The 2012–2018 generation of Ram HD trucks can be susceptible to parasitic draws that drain the battery when the truck is off. Common culprits include the radio and the integrated trailer brake controller. If you experience repeated dead batteries even with a new unit, a parasitic draw test is recommended. For diesel models, it's critical to replace both batteries at the same time. A new battery paired with a weak, old one will have its lifespan significantly shortened as the two batteries fight to equalize, putting a strain on the new unit.

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