2018 GMC Yukon Battery Size, Group & Replacement Guide

As an ASE-certified master technician, I’ve seen countless late-model full-size GM SUVs roll into the bay with electrical gremlins that all trace back to one culprit: a weak battery. The 2018 GMC Yukon is a massive, power-hungry vehicle packed with luxury features, advanced infotainment, and heavy-duty starting requirements. Installing the right battery is critical to keeping your Yukon running reliably.

Quick answer

• BCI Group Size: Group H7 (also known as 94R) is standard for most 2018 Yukons (especially Denali or models with the Max Trailering Package). Group H6 (48) is sometimes found on base models, but H7 is the optimal upgrade.
• Cold Cranking Amps (CCA): 730 to 850 CCA.
• Reserve Capacity: 130 to 140 minutes.
• AGM vs. Flooded: AGM (Absorbent Glass Mat) is highly recommended and often required as OEM for vehicles equipped with heavy electrical loads.
• Terminal Layout: Standard top post, Right Positive (SAE).
• Physical Dimensions (H7/94R): 12.4" L x 6.9" W x 7.5" H.
• Dual-Battery Setup: Not standard on civilian gas 5.3L/6.2L Yukons, though police/fleet variants (or aftermarket overland builds) often utilize the empty auxiliary tray under the hood for a secondary battery.

Replacement battery options

When replacing the battery in your 2018 Yukon, going with a premium brand pays off in longevity. Here are a few top-tier replacements that fit perfectly:

• ACDelco Gold / Professional AGM: Part # 94RAGM (Often the direct OEM replacement, highly trusted for GM vehicles).
• Interstate Batteries MTX AGM: Part # MTX-94R (Excellent warranty and widespread availability).
• DieHard Platinum AGM: Part # 94R (A robust choice with great cold-weather performance).
• Odyssey Extreme Series: Part # ODP-AGM94R H7 (Premium tier, massive cranking power for extreme conditions).
• Optima YellowTop: Part # DH7 (Deep cycle and starting battery combo, great if you run a lot of accessories with the engine off).

AGM vs flooded — which does this vehicle need?

While some base-trim Yukons originally shipped with standard flooded lead-acid batteries, an AGM battery is heavily recommended for the 2018 GMC Yukon. Why? This generation of GM SUVs features massive electrical demands: heated and cooled seats, rear-seat entertainment systems, magnetic ride control, power liftgates, and advanced infotainment systems.

AGM batteries handle deep discharges and heavy accessory loads much better than traditional flooded batteries. They also recharge faster and are vibration-resistant. If your Yukon is a Denali, has the 6.2L V8, or is heavily optioned, do not downgrade to a flooded battery. Stick with AGM to prevent premature failure.

Post-installation relearn / reset procedure

Modern GM vehicles like the 2018 Yukon feature a Battery Management System (BMS) that monitors battery age and state of charge. When you install a new battery, the system needs to know so it doesn't overcharge the new unit (which it does to compensate for an old, degraded battery).

1. BMS Reset: A professional scan tool is the best way to reset the Battery Sensor Module. Alternatively, GM's passive relearn requires you to let the vehicle sit undisturbed (doors locked, key fob far away) for at least 4 to 8 hours so the sensor can learn the new resting voltage.
2. Power Windows: You may need to relearn the express up/down feature. Roll the window all the way down and hold the switch for 3 seconds. Roll it all the way up and hold the switch for 3 seconds. Repeat for each window.
3. Steering Angle Sensor: Turn the steering wheel lock-to-lock (all the way left, all the way right) while parked to reset the StabiliTrak steering angle sensor if you see a warning light.

Signs of a failing battery

Don't get stranded. Watch for these common signs that your Yukon’s battery is on its way out:

• Slow Engine Crank: The 5.3L and 6.2L V8s require a lot of juice to turn over. If it sounds sluggish, get the battery tested.
• Electrical Gremlins: The infotainment screen flickering, radio resetting, or power running boards deploying slowly.
• StabiliTrak Warnings: A dying battery often triggers random "Service StabiliTrak" or "Service Trailer Brake" messages on the dash due to low voltage during cranking.
• Clicking on Startup: The classic rapid clicking noise means the battery lacks the amps to engage the starter solenoid.

Common battery issues for this generation

The 2015–2020 generation of GM full-size SUVs (Yukon, Tahoe, Suburban, Escalade) are notorious for minor parasitic drains. Software glitches in the infotainment system or an improperly sleeping telematics module (OnStar) can slowly drain the battery overnight. If you find yourself replacing batteries every year, have a technician perform a parasitic draw test and check for any outstanding software update bulletins (TSBs) for the radio and body control module.

Additionally, the heavy-duty alternator cables in this generation can sometimes suffer from high resistance due to corrosion at the crimps, leading to undercharging. Keep those terminals clean!

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