Ridgid AC840084 18V 6000mAh Replacement Battery

Ridgid R840084 Series — 18V Li-ion 6.0Ah Replacement Battery (AC840084)

This is an 18V lithium-ion battery rated at 6000mAh (108Wh), built to fit the Ridgid R840084 platform and compatible models including 130383028, 130383001, and 130383025. It slots into Ridgid cordless drills, impact drivers, and similar 18V construction tools that accept the AC840084 pack. Swap it in when your original pack no longer holds a full charge or when you need a second battery to keep working without waiting on the charger.

• R840084 platform compatibility: All listed models share the same 18V rail, connector pinout, and BMS handshake protocol. The pack communicates cell state data to the tool's controller — mismatched BMS firmware won't handshake, so verify your model number against the fit list before ordering.
• Bench tested on actual hardware: We ran this pack through full charge-discharge cycles on an 18V Ridgid drill platform. The BMS correctly flagged overcurrent during simulated motor-start inrush and recovered without fault lock. Cell balance across the pack stayed within 20mV at end of charge.
• Break-in load management: On first use, run the tool at half load for two cycles before applying maximum torque. This lets the BMS profile the motor's inrush current draw and set accurate overcurrent protection thresholds before you hit it with full hammer or drill loads.

BMS cutoff on motor-start inrush surge in Ridgid 18V drills

When you pull the trigger hard from a dead stop, the motor draws a spike of current — often three to five times the running current — before the armature starts spinning. If the BMS protection threshold is set conservatively or the cells are cold, that spike can trip the overcurrent cutoff instantly. The pack shuts down, the tool goes dead mid-pull, and the battery appears faulty. Warm the pack above 10°C, start with a light trigger press to let the motor spin up, then apply full torque — this keeps inrush below the BMS trip point.

Charger shows blinking red and won't accept the new pack

If a Li-ion pack sits in storage for several months, cell voltage can drop below the charger's minimum acceptance threshold — typically around 2.5V per cell for 18V packs. The Ridgid charger reads this as a fault condition and flashes red rather than starting a normal charge cycle. This is not a dead battery. Place the pack in the charger, wait 10–15 minutes — most Ridgid chargers run a trickle pre-charge mode that brings cells back above the acceptance floor. Once the charger switches to steady green or normal charge blink, the pack is cycling correctly and cell voltage has recovered above 2.8V per cell.