The 2020 Ram 3500’s battery setup depends on the engine: diesel models use two 12‑volt batteries (a dual‑battery system), while gasoline models typically use a single 12‑volt battery. For the diesel, each battery is commonly a Group Size 65R unit with roughly 730–750 cold-cranking amps (CCA) per battery. Exact sizes can vary by trim and options, so always verify with the battery label or the dealer.
This article explains the typical configurations, maintenance considerations, how to confirm the exact size for your vehicle, and where to find the official specifications.
Battery configurations by engine
Before listing the typical configurations, note that Ram’s HD lineup shows distinct battery arrangements for diesel versus gasoline engines. The following outlines reflect common factory setups observed in 2020 Ram 3500 models.
- Diesel 6.7L Cummins: two 12‑volt batteries in a dual‑battery system, generally Group Size 65R on each battery, with about 730–750 CCA per battery.
- Gasoline 6.4L Hemi: a single 12‑volt battery, typically Group Size 65 or 65R, depending on trim and equipment choices.
Battery sizing can vary by production run and regional specifications, so use the label on the actual battery or the owner’s manual to confirm the exact size for your truck.
Maintenance and replacement considerations
When replacing or upgrading, keep in mind the diesel model’s dual‑battery layout and the gasoline model’s single battery. Matching specifications and ages across batteries is important for reliable starting power and accessory performance.
- Diesel models: replace batteries in pairs to maintain balanced starting power and electrical load handling.
- Choose the correct type and rating (flooded lead‑acid or AGM, per manufacturer guidance) and avoid mixing old and new batteries with different capacities.
- Ensure proper terminal cleanliness, secure mounting, and correct torque on hold‑downs to prevent charging or connection issues.
Following these guidelines helps preserve starting reliability, especially in cold weather or when using aftermarket accessories.
How to confirm the exact size for your vehicle
To verify the precise battery size and rating for your 2020 Ram 3500, use these steps:
- Check the label on each OEM battery for group size (for example, 65R) and CCA rating.
- Consult the owner's manual or Ram’s official parts catalog using your VIN to pull the exact spec for your build.
- Inspect under the hood to identify whether you have a single (gasoline) battery or a dual (diesel) battery setup.
These steps help ensure you select the correct replacement and avoid compatibility issues.
Summary
The 2020 Dodge Ram 3500 uses a dual‑battery setup in diesel configurations (two 12‑V batteries, commonly Group Size 65R, ~730–750 CCA each) and a single 12‑V battery in gasoline configurations (typically Group Size 65 or 65R). Always verify the exact size and rating on the battery label or through the manufacturer documentation for your specific VIN and trim.
Why does the 6.7 Cummins have two batteries?
They serve as engine heaters, preheating the combustion chambers to assist with engine start. This is required when running a diesel engine in colder temperatures. Operating two batteries ensures better operation in any weather. You need all the cold-cranking amps to get your diesel engine going.
What kind of battery does a Dodge Ram 3500 take?
Most Ram 3500 models use Group 65 or 94R batteries, while diesel trims may use dual Group 94R/78 batteries.
What size battery does a 2020 Dodge Ram take?
DieHard Platinum AGM – Battery : H8 Group Size, 900 CCA, 1000 CA, 160 Minute Reserve Capacity (Part No. H8-AGM)
What size battery does a Dodge Ram 3500 diesel take?
Most Ram 3500 trucks use dual Group 94R or 65 batteries, depending on engine and trim. Are AGM batteries good for diesel engines? Yes. AGM batteries like X2Power deliver superior starting power for diesel applications.