2025 GMC Sierra 1500 Battery Size & Group Specs

As an ASE-certified master technician, I've serviced countless GM trucks. The 2025 GMC Sierra 1500 is a highly advanced piece of machinery, packed with sophisticated electronics, Auto Start-Stop technology, and demanding powertrains. Whether you are running the 2.7L TurboMax, the classic 5.3L or 6.2L V8s, or the 3.0L Duramax inline-six diesel, having the correct battery is critical to keeping your truck on the road.

Here is your comprehensive guide to the battery specifications, group sizes, and replacement procedures for the 2025 GMC Sierra 1500.

Quick Answer: 2025 GMC Sierra 1500 Battery Specs

When it's time to replace the battery in your 2025 Sierra 1500, here are the exact specifications you need to look for:

• BCI Group Size: Group H7 (also known as 94R) is standard for most trims and engines. Some specific configurations or heavy-duty towing packages may step up to an H8 (49) size.
• Cold Cranking Amps (CCA): 730 to 850 CCA (Diesel and 6.2L V8 models typically require the higher 850 CCA rating).
• Reserve Capacity (RC): 140 to 160 minutes.
• Battery Type: AGM (Absorbent Glass Mat) is absolutely required.
• Terminal Layout: Standard SAE top post, Right Positive (when viewing from the front of the battery).
• Physical Dimensions (H7/94R): Approximately 12.4" Length x 6.9" Width x 7.5" Height.
• Diesel Considerations (3.0L Duramax): Unlike the heavy-duty 2500/3500 trucks that use a dual-battery Group 31 or dual H7 setup, the Sierra 1500 3.0L Duramax diesel utilizes a single, high-capacity H7 or H8 AGM battery.

Replacement Battery Options

You should always opt for a premium brand when dealing with a modern GM truck. Here are a few highly recommended, exact-fit H7/94R AGM replacements:

• ACDelco Gold / Professional AGM: Part # 94RAGM (OEM replacement, highly recommended for seamless integration)
• Interstate Batteries MTX AGM: Part # MTX-94R
• DieHard Platinum AGM: Part # 94R (Available at Advance Auto Parts/Carquest)
• Optima YellowTop: Part # DH7 (Excellent deep-cycle and starting capabilities for trucks with winches or aftermarket lighting)
• Odyssey Extreme Series: Part # ODP-AGM48 H7 L3 (Premium tier for extreme conditions and high accessory loads)

AGM vs Flooded — Which Does This Vehicle Need?

The 2025 GMC Sierra 1500 must use an AGM (Absorbent Glass Mat) battery. Do not downgrade to a traditional flooded lead-acid battery.

Why? Modern Sierra 1500s are equipped with Auto Start-Stop systems, high-draw infotainment centers, and complex Battery Management Systems (BMS). A flooded battery simply cannot handle the frequent, high-amp cycling required to restart the engine dozens of times a day while keeping the cabin electronics powered. Downgrading to a flooded battery will result in a severely shortened battery lifespan, disabled Auto Start-Stop, and potential electrical gremlins.

Post-Installation Relearn / Reset Procedure

Like most modern vehicles, the 2025 Sierra 1500 features a Battery Management System (BMS) that tracks battery age and adjusts the alternator's charging output accordingly.

When you install a new battery, the BMS needs to be reset so it doesn't overcharge and cook the new AGM battery:

1. Scan Tool Method (Preferred): Use an advanced OBD2 diagnostic scan tool to access the Body Control Module (BCM) and perform a "Battery Sensor Reset" or "Battery Replacement Relearn."
2. Self-Learn Method: If you don't have a scan tool, GM vehicles can often perform a self-relearn. After installing the new battery, close all doors, lock the truck, and leave it completely undisturbed for at least 4 to 8 hours (overnight is best). The BMS will read the new battery's resting state of charge and recalibrate.

Signs of a Failing Battery

Keep an eye out for these symptoms indicating your Sierra's battery is on its way out:

• Auto Start-Stop disabled: The computer will automatically disable this feature to conserve power if battery voltage drops below a certain threshold.
• Slow or hesitant engine cranking, especially on cold mornings or in the 3.0L diesel.
• Flickering interior lights or dashboard screens when cranking the engine.
• "Service Battery Charging System" warning message on the Driver Information Center.

Common Battery Issues for This Generation

While the current generation of the Sierra 1500 is robust, there are a few common electrical quirks. Parasitic draws from over-the-air (OTA) update modules or malfunctioning infotainment systems have been known to drain batteries prematurely. Additionally, because the battery is situated in the engine bay where it is exposed to extreme heat, AGM batteries in southern climates may face a shorter lifespan (typically 3 to 4 years) compared to those in moderate climates.

If you're unsure about testing or replacing your Sierra's battery, leave it to the professionals. Find a trusted shop on Repairius.