2021 Chevrolet Silverado 1500: Battery Size & Group
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Quick answer
- BCI group size: H6/48 or H7/94R (optional)
- Cold cranking amps (CCA): 730 (H6), 850 (H7)
- Reserve capacity: 120 minutes (H6), 140 minutes (H7)
- AGM vs flooded requirement: AGM required
- Terminal layout: Top post
- Physical dimensions (L x W x H):
- H6: 10.9 x 6.9 x 7.5 inches
- H7: 12.4 x 6.9 x 7.5 inches
- Dual-battery setup: Not applicable for 1500 models
Replacement battery options
- Interstate: MTX-48/H6, MTX-94R/H7
- Optima: DH6 YellowTop, DH7 YellowTop
- DieHard: Platinum AGM H6, Platinum AGM H7
- Odyssey: ODP-AGM48 H6, ODP-AGM94R H7
- ACDelco: 48AGM, 94RAGM
AGM vs flooded — which does this vehicle need?
The 2021 Chevrolet Silverado 1500 requires an absorbed glass mat (AGM) battery. The truck's start-stop technology and sophisticated electronics demand the faster charging, deeper cycling, and vibration resistance that AGM batteries provide. A conventional flooded lead-acid battery will not be able to meet the demands of the vehicle and will fail prematurely.
Post-installation relearn / reset procedure
After replacing the battery, you must perform a battery relearn procedure. This ensures that the truck's battery monitoring system is calibrated to the new battery, which is crucial for optimal performance and longevity. The relearn procedure can be performed with a scan tool or by following these steps:
- Turn the ignition to the "On" position (do not start the engine).
- Wait for the instrument cluster to boot up.
- Turn the headlights on for 5 minutes.
- Turn the headlights off.
- Start the engine.
The battery monitoring system will now be reset. It may take several drive cycles for the system to fully calibrate to the new battery.
Signs of a failing battery
- Slow engine crank
- Dimming headlights
- Warning lights on the dash
- Corrosion on the battery terminals
- A swollen or leaking battery case
Common battery issues for this generation
The most common battery issue for this generation of Silverado is premature failure due to the demands of the start-stop system. If you frequently make short trips, the battery may not have enough time to fully recharge, which can lead to a shortened lifespan. To avoid this, it is recommended to use a battery tender if the truck is not driven daily.
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More specs for the 2021 Chevrolet Silverado 1500
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Fuse Box Diagram & Amperage
Fuse box locations, layout, amps, and what each fuse controls.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Transmission & Axle Gear Ratios
Trans gear ratios, axle ratios, RPO codes, tow vs MPG impact.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
2000 Silverado 1500
2001 Silverado 1500
2002 Silverado 1500
2003 Silverado 1500
2004 Silverado 1500
2005 Silverado 1500
Maintenance & repair guides
2021 Chevrolet Silverado 1500 Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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Values can vary by engine, trim and build date; check your VIN-specific service information. Updated 2026-08-28.