Milwaukee 28V M28 Replacement Battery 4000mAh Li-ion

Milwaukee V28 Series — 28V Li-ion Replacement Battery (48-11-2830)

This is a 28V Li-ion replacement battery rated at 4000mAh (112Wh) for the Milwaukee V28 cordless tool platform. It fits the M28, M28B, M28BX, and MC28 battery housings, along with tools like the 0726-22 and 0780-20. Voltage and connector match the original Milwaukee V28 specification.

• V28 platform compatibility: All tools in Milwaukee's 28V line share the same battery rail voltage, slide-in connector, and BMS communication protocol. That includes V28 drills, circular saws, reciprocating saws, and impact drivers — the battery seats and handshakes identically across the platform.
• Bench tested on actual hardware: We ran this pack through a Milwaukee V28 drill and circular saw under load. The BMS handled motor-start inrush without false overcurrent trips and held the voltage rail steady through sustained cutting cycles. Cell balance across the pack stayed within spec at end of discharge.
• V28 motor break-in tip: On first use, run the tool at half load for two cycles before full-torque applications. This lets the BMS log the motor's inrush current signature and calibrate overcurrent thresholds before you hit it with a core drill or sustained saw cut.

BMS cutoff on V28 motor-start inrush surge

Milwaukee V28 motors — especially circular saws and hammer drills — pull a sharp current spike the instant the trigger engages. A new or storage-aged battery pack can read that spike as an overcurrent fault and shut the BMS down before the motor reaches speed. The BMS protection threshold is factory-set conservatively; a pack that hasn't been cycled recently hasn't profiled the motor load yet. Running two light-load cycles lets the BMS establish a current baseline and reduces nuisance trips on full-trigger engagement.

Charger showing red fault light on a new V28 pack after storage

If the Milwaukee charger blinks red and refuses to start a charge cycle, the pack's resting voltage has likely dropped below the charger's acceptance threshold — typically under 20V on a 28V pack after extended storage. The charger interprets this as a damaged or deeply discharged cell and blocks the charge for safety. To recover it, use a charger with a conditioning or recovery mode, or briefly connect the pack to a known-good V28 charger and watch for a slow pulse rather than a solid fault light. Once the voltage climbs above the acceptance floor — around 22V — a standard charge cycle will proceed normally.