Stanley 18V FMC687L Cordless Drill Replacement Battery 2000mAh

Stanley FMC688L Series — 18V Li-ion Replacement Battery (FMC687L)

This is an 18V, 2000mAh Li-ion replacement battery carrying OEM part number FMC687L. It fits the Stanley FMC688L, PCC680L, PCC685L, PCCK602L2, and 12 additional models across the 18V cordless platform. Slide it into the same battery slot and connect to the same charger as the original pack.

• 18V platform compatibility: The FMC688L, PCC680L, and PCC685L all share the same 18V rail, connector pinout, and BMS handshake protocol. One battery pack covers drills, impact drivers, and combo kit tools across this entire line without adapter modification.
• Bench tested on actual hardware: We ran this pack on an FMC688L drill through repeated trigger pulls and sustained load cycles. The BMS held the overcurrent threshold correctly on motor start and cut discharge cleanly at the low-voltage floor — no false trips, no thermal events.
• Motor inrush break-in on first use: On first use, run the tool at half load for two full discharge-and-charge cycles before applying maximum torque. This lets the BMS profile the motor's inrush current draw and calibrate overcurrent thresholds before you put the pack under peak load.

BMS Cutoff on Motor-Start Inrush — Why the Drill Trips on Trigger Pull

At the moment the trigger engages, a brushed or brushless motor draws a spike of current two to five times its running load — this is inrush. If the BMS has no stored profile for that motor, it can read the spike as a fault and cut the pack instantly. The FMC687L BMS uses a short blanking window to ride through legitimate inrush, but a deeply discharged or cold pack narrows that window. If you see the tool cut out on first trigger pull, charge the pack fully to 18V before retrying.

Charger Blinks Red and Never Advances on a New Pack from Storage

Stanley 18V chargers reject packs whose cell voltage sits below the charger's acceptance threshold — typically around 12–13V for an 18V Li-ion pack. Packs stored for months can self-discharge past that floor, and the charger reads this as a defective or over-discharged cell and blinks red without initiating a charge cycle. Some Stanley chargers include a recovery or "wake-up" mode: leave the pack seated for 30 minutes and the charger may trickle current in to raise cell voltage back above the threshold before switching to normal charge. If the light stays red past 30 minutes, check cell voltage at the pack terminals — anything below 10V indicates a cell has dropped too far for recovery.