2023 GMC Sierra 2500HD Battery Size & Specs

Quick answer

• BCI group size: Group 48 (also called H6) for the 6.6L gasoline V8, dual Group 48/H6 for the 6.6L Duramax diesel V8.
• Cold cranking amps (CCA): 760 CCA (gas) or dual 760 CCA (diesel).
• Reserve capacity: Approximately 120 minutes (gas) or 120 minutes per battery (diesel).
• AGM vs. flooded: AGM (Absorbent Glass Mat) is required.
• Terminal layout: Top post, right-hand positive (Layout 0).
• Physical dimensions (approximate): 11" L x 7" W x 7.5" H.
• Dual-battery setup: Yes, the diesel model uses a dual-battery setup for increased starting power and to handle the demands of the glow plugs.

Replacement battery options

• Interstate MTX-48/H6
• DieHard Platinum AGM H6
• Odyssey ODP-AGM48 H6 L3
• ACDelco Gold 48AGM

AGM vs flooded — which does this vehicle need?

The 2023 GMC Sierra 2500HD requires an AGM (Absorbent Glass Mat) battery from the factory. This is due to the advanced electronics, start-stop systems, and higher electrical demands of the vehicle. You should not replace the AGM battery with a conventional flooded battery, as it will not perform adequately and may cause electrical issues. AGM batteries are designed to handle the deeper cycling and higher current draws of modern vehicles.

Post-installation relearn / reset procedure

After replacing the battery on a 2023 GMC Sierra, a reset procedure is necessary to ensure the Battery Management System (BMS) correctly charges the new battery. This system monitors the battery's state of charge and health over time, and if it isn't reset, it may overcharge or undercharge the new battery, significantly shortening its lifespan. The reset procedure typically involves connecting a diagnostic scan tool to the OBD-II port to inform the BMS that a new battery has been installed.

Signs of a failing battery

• Slow engine crank: The engine turns over more slowly than usual when you try to start it.
• Dimming lights: Headlights and interior lights may dim, especially during startup.
• Warning lights: A battery or check engine light may appear on the dashboard.
• Clicking sound: A rapid clicking sound when you turn the key indicates the battery doesn't have enough power to engage the starter.
• Visible corrosion: A white or bluish powder around the battery terminals is a sign of a leak.

Common battery issues for this generation

• Parasitic draw: The complex electronics in modern trucks can sometimes cause a "parasitic draw," where a component continues to draw power even when the vehicle is off, leading to a dead battery.
• BMS calibration errors: If the battery is not correctly registered with the BMS after replacement, it can lead to premature failure of the new battery.

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