The 2016 Ram 2500 diesel uses two 12-volt lead-acid batteries in a dual-battery setup, not a single large battery. Replacement typically means two matching batteries with high cold-cranking amps (CCA); always verify the exact group size and CCA from the OEM battery label or the owner's manual.
In more detail, Ram’s heavy-duty trucks equipped with the 6.7-liter Cummins diesel rely on substantial cranking power and electrical support, which is why they use a dual-battery system. The precise group size, CCA, and capacity can vary by production run and market, so it's important to confirm specifications against your VIN or the current battery label before purchasing replacements.
Battery configuration for the 2016 Ram 2500 diesel
Before shopping for a replacement, understand the layout and key specs.
- Two 12-volt lead-acid batteries are installed in a dual-battery tray in the engine bay (one on each side in some builds).
- The batteries are wired to provide ample cranking power for the Cummins diesel and to support electrical loads when the engine is off.
- The OEM group size and CCA vary by production run and market; common replacement options include several large group sizes such as 65R, 78, or 75/78 configurations. Always confirm from the current battery label or dealer documentation.
- Expected capacities per battery are in the typical heavy-duty range; exact Ah and CCA should be taken from the battery you plan to purchase and matched to the OEM specs.
Choosing two matching batteries with the correct group size and sufficient CCA ensures reliable starting and electrical performance for your diesel Ram.
Replacing or selecting the right batteries
Use this practical guide if you are swapping the batteries yourself or choosing replacements for service. It covers safety steps and fitment considerations.
- Park on a level surface, apply the parking brake, and wear eye protection and gloves.
- Disconnect the negative terminals on both batteries first, then disconnect the positive terminals.
- Remove the battery hold-downs, disconnect cables from the batteries, and lift the old batteries out of the tray.
- Compare the new batteries with the old ones to ensure identical group size, terminal layout, and height, then install them in the reverse order of removal.
- Connect the positive terminals first, then the negative terminals, snug the clamps securely, and reconnect any battery disconnect if your vehicle uses one.
- Start the engine to confirm cranking performance and electrical system operation; dispose of the old batteries at an approved recycling facility.
If you cannot determine the correct group size or CCA from the vehicle labels, contact a Ram dealer or consult the owner's manual before purchasing to avoid fitment or compatibility issues.
Summary
In short, a 2016 Ram 2500 diesel uses a dual 12-volt battery setup, requiring two matching batteries with appropriate CCA and group size. Verify the exact specifications from the owner's manual or the existing battery label, and follow proper safety steps when replacing. With the right pair, your Ram will start reliably and run all electrical loads effectively.