The 2019 Silverado 2500HD Duramax uses two 12-volt batteries in a dual-battery setup. Replacement batteries are typically Group Size 96R or 94R, paired to match in capacity; always verify with the label on your current batteries or GM’s specifications.
What the diesel system requires
The Duramax diesel’s electrical demand is higher than a typical gasoline setup, so GM equips the heavy-duty trucks with two 12‑volt batteries to provide sufficient cold‑start power and electrical support. Replacement group sizes commonly seen for this dual-battery arrangement are 96R or 94R, though exact fit can vary by model year, trim, and battery tray configuration. Always check the existing batteries or the owner's manual for the exact requirement.
Before you dive into replacements, it helps to know which battery sizes are commonly used in this truck and what compatibility means for fit and performance.
- Group Size 96R — a frequent fit for dual-battery GM trucks; designed to work with diesel‑start requirements and heavier electrical loads.
- Group Size 94R — another common option; offers a slightly different footprint while supporting the same dual‑battery setup.
- AGM option — some owners opt for AGM batteries for better high‑load performance and longer life; ensure your charging system and tray fit are compatible.
When replacing, always use two batteries of the same group size and similar capacity. Mixing new and old batteries or mismatched capacities can cause charging imbalance and reduce reliability.
How to choose and install the batteries
Key specifications to consider when selecting a replacement include the group size, cold-cranking amps (CCA), reserve capacity (RC), and the battery type (flooded lead-acid vs AGM). The Duramax’s diesel system benefits from higher CCA and adequate RC, and you should confirm compatibility with the dual-battery setup for optimal performance.
- Park on level ground, apply the parking brake, and turn off the engine and all accessories. Wear eye protection and gloves as a precaution.
- Disconnect the negative (-) battery cable first, then the positive (+) cable from each battery. Remove any hold-down brackets or trays securing the batteries.
- Take out the old batteries and inspect the trays for corrosion or damage. Clean the tray area if needed.
- Install the new batteries in the same orientation as the originals and secure them with the hold-downs.
- Connect the positive (+) terminal first, then the negative (-) terminal on each battery to minimize arcing.
- Ensure the interconnection between the two batteries (if applicable) is correctly installed so they operate in parallel as designed.
- Start the engine and verify the charging system operates normally with no warning lights; if in doubt, have a professional check the alternator and wiring.
If you’re not comfortable performing a dual‑battery replacement, consider a professional install to avoid injury or damage to the vehicle’s electrical and diesel systems.
Summary
The 2019 Chevy Silverado 2500HD Duramax uses two 12-volt batteries in a dual-battery setup. Replacement group sizes commonly seen are 96R or 94R, and you may encounter AGM options if you choose an upgrade. Always replace both batteries together and verify fit and capacity with the OEM specifications or battery labels. For peace of mind, a professional installation is advised if you’re unsure about the process.