2018 Kenworth T680 Battery Size & Group

Quick answer

• BCI Group Size: Group 31
• Cold Cranking Amps (CCA): 950-1100 CCA per battery
• Reserve Capacity: 190-220 minutes per battery
• AGM vs. Flooded: AGM (Absorbed Glass Mat) is strongly recommended.
• Terminal Layout: Top post (standard SAE posts)
• Physical Dimensions: Approximately 13" x 6.8" x 9.5" (L x W x H)
• Dual-battery setup: Yes, typically a four-battery setup (four Group 31 batteries).

Replacement battery options

• Interstate: 31-AGM, 31-HD
• Optima: YellowTop D31A
• DieHard: 31-AGM
• Odyssey: 31-PC2150S
• ACDelco: 31-AGM

AGM vs flooded — which does this vehicle need?

The 2018 Kenworth T680, like most modern heavy-duty trucks, benefits significantly from AGM (Absorbed Glass Mat) batteries. While standard flooded lead-acid batteries will work, they are not ideal for the high-vibration environment and the significant electrical demands of a modern semi-truck. The T680's complex electronics, sleeper cab amenities (like refrigerators, inverters, and climate control), and anti-idling regulations make AGM batteries the superior choice. They are more resistant to vibration, are spill-proof, and offer better deep-cycle performance, which is crucial when the engine is off and you are relying on battery power.

Post-installation relearn / reset procedure

There is no specific relearn or reset procedure required after disconnecting or replacing the batteries in a 2018 Kenworth T680. However, it is good practice to ensure all connections are clean and tight. After installation, start the engine and let it run for a few minutes to allow the electronic control modules (ECMs) to re-initialize. You may need to reset your radio presets and clock.

Signs of a failing battery

• Slow engine crank: The engine turns over sluggishly, especially in cold weather.
• Dimming lights: Headlights and interior lights dim when the engine is off or at idle.
• Warning lights: A battery or alternator warning light may appear on the dashboard.
• Frequent jump-starts: You find yourself needing to jump-start the truck regularly.
• Corrosion: Visible corrosion on the battery terminals.

Common battery issues for this generation

The most common battery issue for this generation of Kenworth T680 is premature battery failure due to the high electrical loads and the harsh operating environment. Using standard flooded batteries instead of AGMs can lead to shorter battery life. Additionally, loose or corroded battery cables are a frequent cause of starting and charging problems.

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