DeWalt DC9180 18V Replacement Battery 4000mAh Li-ion

DeWalt DCD925 Series — 18V Li-ion Replacement Battery (DC9180)

This 18V 4000mAh lithium-ion battery replaces the DC9180, DC9180C, and DC9182 OEM packs. It fits the DeWalt DCD925, DCD925N, DCD925B2, and DCD925KA compact drill/drivers. Voltage and connector match the original — the pack seats and latches the same way the factory unit does.

• DCD925 platform fit: All four DCD925 variants share the same 18V slide-rail connector and BMS handshake protocol. The pack communicates state-of-charge to the tool's control board the same way the OEM unit does — no pairing step required.
• Bench tested on actual hardware: We ran this pack on a DCD925B2 through repeated drill and drive cycles. The BMS tracked inrush current on each trigger pull and held the protection threshold steady across all test cycles without nuisance tripping.
• Motor inrush break-in on first use: Run the drill at half load — light drilling, no maximum torque — for two full charge cycles before heavy fastening work. This lets the BMS sample the motor's inrush current signature and set its overcurrent threshold accurately before you start driving large-diameter fasteners.

BMS cutoff on DCD925 motor-start inrush surge

When you pull the trigger on a stalled or heavily loaded fastener, current draw spikes hard in the first 20–40 milliseconds. A cold pack — or one that has been sitting discharged — has higher internal resistance, which pushes that spike above the BMS overcurrent threshold. The BMS reads this as a fault and cuts the output rail before the motor reaches speed. Warming the pack to room temperature before use and keeping rail contacts clean reduces resistance enough to keep that spike below the trip point.

Charger blinking red on the DC9180 pack after storage

DeWalt 18V chargers check cell voltage before starting a charge cycle. If the pack has sat discharged long enough for cells to drop below roughly 2.5V per cell, the charger rejects it and blinks red rather than beginning a standard charge. Some chargers have a recovery mode — insert the pack, wait 30 seconds, then remove and re-insert to trigger a low-current trickle phase. If the cells recover above 2.5V per cell during trickle, the charger transitions to normal charge automatically.