The 2018 RAM 2500 uses a standard 12-volt lead-acid automotive battery. Diesel models typically require two batteries, while gasoline models use a single battery. The exact group size and specifications depend on the engine and trim, so verify the rating on the current battery or in the owner's manual before purchasing a replacement.
Battery configurations by engine
Battery setups for the 2018 RAM 2500 vary by powertrain. Here are the typical configurations you’ll encounter.
- Gasoline-powered RAM 2500: Usually equipped with a single 12-volt battery. Replacement should be a 12V lead-acid battery with adequate cold-cranking amps (CCA) to meet or exceed the original rating. The specific group size is shown on the original battery label or in the owner's manual.
- Diesel-powered RAM 2500 (Cummins 6.7L): Uses a dual-battery system, with two 12-volt batteries working in tandem to meet higher starting demands. Each battery should be matched in type and CCA, and replacements are best done in pairs to maintain balanced performance.
The exact battery group size (the numerical designation on the battery label such as Group Size 65 or 75) can vary by model year and trim. Always verify using the label on your battery or the vehicle’s manual.
Choosing the replacement: what to look for
When selecting a replacement battery, consider the following factors to ensure compatibility and reliability in the field.
- Engine type and configuration: Confirm whether your truck is gasoline or diesel, as this determines single versus dual battery needs.
- Group size and terminals: Use the OEM-recommended Group Size and ensure the terminal layout matches your vehicle’s cables and clamps.
- Cold-cranking amps (CCA): Diesel variants typically require higher CCA; aim for a battery (per unit) that meets or exceeds the OEM specification, commonly in the 700–800 CCA range or higher per battery for dual setups.
- Type and construction: The factory battery is a flooded lead-acid unit; AGM options can offer longer life in certain climates, but compatibility with the RAM’s electrical system should be confirmed.
- Replacement in diesel models: If your truck has the dual-battery setup, replace both batteries at the same time to maintain balanced performance and avoid stressing the alternator.
Always prefer OEM-specified or OEM-approved aftermarket batteries, and consult a dealer or trusted auto parts retailer if you’re unsure about compatibility with your specific VIN.
How to confirm the exact battery size for your truck
To ensure you buy the correct battery, check these sources and indicators.
- Inspect the current battery: Read the “Group Size” and “CCA” ratings printed on the battery label.
- Consult the owner's manual or Ram official documentation for the exact group size and spec for your model year and engine.
- If in doubt, provide your VIN to an auto parts retailer or RAM dealership to get a precise match.
Matching the correct group size and electrical specs protects electrical components and helps avoid starting and charging issues.
Summary
In brief, a 2018 RAM 2500 uses a 12-volt lead-acid battery, with gasoline models typically using a single battery and diesel models using a dual-battery system. The precise group size and CCA depend on the engine and trim, so verify the battery label or the owner’s manual to purchase the correct replacement. Replacing batteries in pairs for diesel versions and ensuring compatibility with the vehicle’s electrical system will help maintain reliable performance.