2018 Ram 1500 — Battery Size & Group

Quick answer

• BCI group size: Primary fit is H7/94R (most 3.6L and 5.7L gas, and 3.0L EcoDiesel). Some trims may accept H6/48 as an alternate size.
• Cold cranking amps (CCA): Target 730–850 CCA for H7/94R; 680–800 CCA if using H6/48.
• Reserve capacity (RC): Typically 140–160 minutes for H7/94R; 120–140 minutes for H6/48.
• AGM vs flooded: Flooded lead‑acid was common OE; AGM is a recommended upgrade (required only if your truck specifies it or sees heavy accessory/idle use).
• Terminal layout: SAE top posts, reversed polarity (Group 94R) — with the posts closest to you, positive is on the right.
• Physical dimensions: H7/94R ≈ 12.4 x 6.9 x 7.5 in (315 x 175 x 190 mm). H6/48 ≈ 11.0 x 6.9 x 7.5 in (278 x 175 x 190 mm).
• Diesel dual battery: Not used on the 1500, including the 3.0L EcoDiesel (single battery). Dual batteries apply to some 2500/3500 Cummins trucks.

Replacement battery options

These are popular, high‑quality replacements that fit the 2018 Ram 1500. Always verify group size (H7/94R is the primary fit) and terminal orientation before purchase.

• Interstate Batteries: MTP‑94R/H7 (flooded), MTX‑94R/H7 (AGM); MTP‑48/H6 or MTX‑48/H6 if your truck is equipped for H6.
• DieHard (Advance Auto): DieHard Platinum AGM H7‑AGM; DieHard Gold 94R‑2 (flooded). For H6: H6‑AGM or 48‑2.
• ACDelco: 94RAGM (AGM) or 94R (flooded, availability varies). For H6: 48AGM.
• Odyssey: ODP‑AGM94R H7 (Performance/Extreme series variants available). For H6: ODP‑AGM48 H6.
• Optima: YellowTop DH7 (AGM) for 94R/H7; DH6 (AGM) for H6/48.

Never mix part numbers across group sizes; match H7/94R to H7/94R, or H6/48 to H6/48.

AGM vs flooded — which does this vehicle need?

The 2018 Ram 1500 did not use a start/stop system, and most trims were equipped from the factory with a high‑quality flooded 94R battery. AGM is not strictly required, but it is a smart upgrade if:

• You run winches, plows, inverters, upgraded audio, or other high‑draw accessories.
• The truck idles often (fleet/contractor use) or sees short‑trip city driving.
• You live in very hot or very cold climates and want better vibration and heat resistance.

If your build sheet or owner’s manual specifies AGM, stick with AGM. Otherwise, either flooded or AGM in the correct group size and CCA will work.

Post-installation relearn / reset procedure

Using a memory saver during the swap avoids most resets. If the battery was disconnected, do the following after reconnection:

1. Initial power-up

• Turn ignition to RUN (engine off) for ~30 seconds to let modules wake up. You may hear HVAC actuators calibrate.

2. Idle/throttle relearn

• Start the engine and let it idle in Park for 3–5 minutes with all accessories off.
• Then turn A/C on and let it idle another 3–5 minutes.
• Drive normally, varying speeds and throttle for 10–15 minutes. Transmission and fuel trims will re‑adapt over the next few drive cycles.

3. Power window auto-up/down

• With the door closed, key ON, hold the window switch to fully lower each front window; keep holding for 2 seconds.
• Raise fully and hold for 2 seconds. Repeat once if the express function doesn’t return.

4. Radio/Uconnect and clock

• Re‑set the clock and radio presets as needed. Bluetooth will typically reconnect automatically.

5. Steering angle/ESC

• If the ESC light stays on after the swap, turn the wheel slowly lock‑to‑lock while stopped, then drive straight for a short distance; the system will self‑calibrate.

No special scan‑tool procedures are normally required for a simple battery replacement on the 2018 Ram 1500.

Signs of a failing battery

• Slow crank, especially after the truck sits overnight or in cold weather.
• Intermittent no‑start with a rapid clicking from the starter relay.
• Dim lights at idle that brighten with rpm.
• Uconnect glitches, random warning lights, ABS/ESC faults that clear after charging.
• Corrosion on the positive terminal or a swollen case.

If your battery is 4–6 years old, proactive replacement is smart—especially before winter or a long trip.

Common battery issues for this generation

• Parasitic draw from aftermarket accessories (light bars, audio amplifiers) wired to constant power. Use a fused relay and proper ignition feed.
• Negative battery current sensor (IBS) on the ground cable can skew charging if damaged; handle carefully during replacement and ensure it’s re‑secured.
• Loose or corroded grounds at the fender/body and engine block cause intermittent no‑start and low‑voltage faults—clean and tighten.
• TIPM or radio staying awake after key‑off due to software/accessory wiring can drain the battery overnight; a draw test will confirm.
• Using the wrong group size (too short H6 in an H7 tray without proper clamp relocation) can stress cables and loosen hold‑downs over time—match the tray and clamp.

Match the 2018 Ram 1500 with a quality H7/94R around 730–850 CCA (AGM if you want the upgrade), confirm the reversed‑polarity layout, and you’ll be set for reliable starts and stable electrical performance.

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