Stanley FMC687L 20V Replacement Battery 2000mAh Li-ion

Stanley FMC625D2 Series — 20V Li-ion Replacement Battery (FMC687L)

This is a 20V Li-ion replacement battery rated at 2000mAh (40Wh), compatible with the Stanley FMC625D2 compact drill/driver and a range of related 20V cordless tools including the FMC645D2, FMC675B, and FMC675B-XE. It uses the same voltage rail and connector format as the original FMC687L pack. Fits directly into the tool's battery slot without modification.

• FMC625D2 and compatible 20V platform: These models share a common 20V battery interface — same connector pinout, same BMS communication protocol, and the same voltage rail. A replacement pack that matches these specs will seat and function identically across the group.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a 20V test rig. The BMS correctly responded to overcurrent events and re-engaged after load removal. Cell balancing completed normally across all five cells.
• Break-in procedure for drill and driver use: On first use, run the tool at half load for two cycles before maximum torque applications. This allows the BMS to profile the motor's inrush current draw before it sets its overcurrent protection thresholds — preventing nuisance trips on demanding fastening tasks.

BMS Cutoff on Motor-Start Inrush in the FMC625D2

When you pull the trigger on a drill or driver, the motor draws a spike of current that can be three to five times the running load. On a new or recently stored pack, the BMS overcurrent threshold may not yet be calibrated to the tool's specific inrush profile. If the pack cuts out the instant the trigger is pulled, that is a BMS overcurrent trip — not a faulty cell. Run the pack through one full charge cycle, then test under light load first. Two light-load cycles typically allow the BMS to set appropriate trip thresholds for your tool's motor.

Charger Blinking Red on a New or Stored FMC687L Pack

Stanley's 20V chargers reject packs where individual cell voltage drops below approximately 2.5V — a common result of storage discharge. The charger blinks red because it won't enter the main charge cycle until all cells are above the acceptance threshold. Some chargers include a recovery or wake-up mode: place the pack on the charger, remove it after 30 seconds, and reseat it firmly. Repeat two to three times. If the charger still refuses the pack after three attempts, check rail contact cleanliness and confirm the terminal voltage reads above 15V across the pack before retrying.