Milwaukee 48-11-0100 Cordless Screwdriver Compatible Battery 2.4V

Milwaukee 6550-20 Series — 2.4V Ni-MH Replacement Battery (48-11-0100)

This is a 2.4V, 1500mAh Ni-MH replacement battery for the Milwaukee 6550-20 cordless screwdriver. It also fits the JAN-38, JAN-39, JAN-46, and compatible models sharing the same voltage rail and connector. Capacity is sourced from product data at 1500mAh (3.6Wh).

• 6550-20 and JAN-series compatibility: These models share the same 2.4V single-cell Ni-MH architecture, identical connector footprint, and the same charge acceptance profile. The BMS handshake on each expects the same temperature coefficient response during charging — this pack meets that spec.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the 6550-20 platform. The BMS accepted the pack without fault codes, held stable voltage under repeated trigger-pull loads, and recovered cleanly from a partial discharge state.
• Ni-MH cycling on a compact screwdriver: Ni-MH cells in this voltage class degrade faster from shallow cycling than deep cycling. Run the pack down to tool slowdown before recharging — not after every short use. This keeps cell capacity calibrated and slows voltage depression.

Voltage depression in Ni-MH packs from repeated partial discharge

Ni-MH cells at 2.4V are particularly vulnerable to voltage depression — a condition where the pack delivers less usable voltage than its nominal rating under load. This happens when cells are repeatedly charged before they reach full discharge. In a compact screwdriver like the 6550-20, the symptom appears as sluggish torque even on a freshly charged pack. Running two or three full discharge-recharge cycles on a new or recovered pack resets the electrochemical baseline and restores usable voltage.

Charger not recognising the pack after storage

If the Milwaukee charger shows no activity or a fault indication when you seat this pack, the cell voltage has likely dropped below the charger's acceptance threshold — typically under 1.0V on a 2.4V Ni-MH pack. This happens after extended storage. Connect the pack to the charger and watch for the charge indicator within 90 seconds; some chargers require the cell to read above 0.8V per cell before initiating. If the charger won't engage, a brief manual trickle charge using a universal Ni-MH charger at 50mA for 10–15 minutes will bring the pack above the acceptance floor — then reseat it in the Milwaukee charger.