RAM diesel trucks use a 12-volt starting battery. In practice, the light-duty RAM 1500 EcoDiesel uses a single 12V battery, while the heavy-duty RAM 2500 and 3500 with Cummins diesels rely on two 12V batteries to provide the necessary cranking power. The exact size and type vary by model year and trim, so always check the battery label or the owner's manual for your VIN.
To understand the practical differences, here is a quick breakdown of how the batteries are configured on common RAM diesel setups.
Battery configurations by RAM diesel model
Before listing typical configurations, note that exact specs can vary with equipment packages, idle-stop systems, and climate considerations.
- RAM 1500 with EcoDiesel: typical setup is a single 12‑volt starting battery. Expected cold-cranking amperage (CCA) is generally in the 700–800 range, with replacement batteries sized to fit the tray as indicated on the label.
- RAM 2500/3500 with Cummins diesel: typical setup is two 12‑volt batteries in a dual-battery arrangement. Each battery is usually in the 700–800 CCA range, providing a combined system of roughly 1400–1600 CCA when new.
Note: The exact group size, whether flood lead-acid or AGM, and the presence of a second “house” battery can vary by year and build. Always verify the specs on the battery label or in the service manual for your VIN.
Bottom line: if you own or service a RAM diesel, expect one 12V battery on the 1500 EcoDiesel and two 12V batteries on the heavy-duty Cummins models, with replacement parts in the same CCA range per battery.
Summary
The RAM diesel battery configuration hinges on the model: single 12V battery for RAM 1500 EcoDiesel; dual 12V batteries for RAM 2500/3500 Cummins. Typical per-battery CCA sits in the 700–800 range, with total system capacity higher for the dual-battery setup. Always verify exact specs on the battery label or in the owner's manual for your vehicle year and trim.