Milwaukee 48-11-2001 M4 4V Replacement Battery 2000mAh

Milwaukee M4™ 1/4" Hex Screwdriver — 4V Li-ion Replacement Battery (48-11-2001)

This is a 4V Li-ion replacement battery rated at 2000mAh (8Wh) for the Milwaukee 2102-22 M4™ 1/4" Hex Screwdriver. It uses the OEM part number 48-11-2001 and slots directly into the M4 platform battery dock. When the original pack loses capacity or fails to hold a charge, this unit restores full tool function.

• M4 platform compatibility: The Milwaukee M4 line runs a shared 4V rail with a common battery footprint and BMS handshake. The 2102-22 and other M4 tools draw low sustained current compared to larger cordless platforms, but the BMS still monitors cell voltage and temperature through the same contact array. Any pack without the correct communication response gets rejected at startup.
• Bench tested on actual hardware: We cycled this pack through repeated load sequences on the M4 screwdriver platform and monitored the BMS response across trigger pulls. The overcurrent threshold cleared cleanly at full inrush, and cell voltage held steady across the discharge curve without premature cutoff.
• M4 screwdriver load cycling tip: On first use, run the screwdriver at half load for two cycles before pushing maximum torque applications. This lets the BMS profile the motor inrush current draw and set its overcurrent protection thresholds against real operating conditions — not storage defaults.

BMS cutoff on trigger-pull inrush in the M4 1/4" Hex Screwdriver

The M4 screwdriver motor draws a short inrush spike the moment the trigger closes — this spike is brief but sharp relative to the pack's 4V nominal rail. If a replacement cell has elevated internal resistance from storage or a substandard grade, the BMS reads the voltage dip as an overcurrent event and cuts output instantly. The tool clicks off mid-pull and won't restart until the trigger is released and the BMS resets. A correctly graded 2000mAh cell holds the rail above the BMS trip threshold even during that initial inrush window.

Charger not recognising the 48-11-2001 pack after extended storage

Li-ion cells self-discharge during storage — if the pack sits long enough, cell voltage drops below the Milwaukee charger's acceptance threshold, and the charger stalls with a blinking indicator rather than initiating a charge cycle. This is a protection circuit response, not a dead battery. To recover the pack, connect it to the charger and hold it in place for 60–90 seconds — some M4 chargers will attempt a trickle wake pulse before accepting the pack. If the charger still rejects it, check that the contact pins on the pack base are clean and the cell resting voltage is at or above 2.5V per cell.