Logitech MX Master 3.7V Li-Polymer Replacement Battery AHB303450

Logitech MX Master / MX Anywhere 2 — 3.7V Li-Polymer Replacement Battery (AHB303450)

This is a 3.7V, 450mAh Li-Polymer battery (1.67Wh) that replaces the internal rechargeable cell in the Logitech MX Master and MX Anywhere 2 wireless mice. It matches OEM part numbers AHB303450, 533-000120, 533-000121, 533-000172, 533-000170, 533-000205, and 533-000207. When the original cell degrades and the mouse stops holding charge between sessions, this cell restores normal operation.

• MX Master and MX Anywhere 2 compatibility: Both mice share the same internal battery bay dimensions and connector pinout — 36.84 × 25.20 × 5.60mm with matched voltage and cell chemistry — which is why a single replacement covers both platforms without modification.
• Bench tested on actual hardware: We ran this cell through charge cycles on the MX Master platform and confirmed the BMS accepted full charge without false cutoff, and that charge status reported correctly through the Logitech Options software indicator.
• Connector seating on the MX Master: The JST connector on this cell sits flush only when the locking tab clicks fully. A partially seated connector causes the mouse to report "no battery" in Logitech Options even though the cell is physically present — press the connector in until you feel and hear the click before closing the shell.

Why the MX Master stops reconnecting after a full battery drain

When the Li-Polymer cell discharges below the BMS cutoff threshold — typically around 2.5V — the protection circuit opens and the mouse loses all power, including the memory that maintains its USB receiver pairing. The receiver itself retains the pairing record, but the mouse needs to re-establish the handshake from its end. After fitting a charged replacement cell, hold the Connect button on the underside for three seconds until the LED blinks, then plug the Unifying receiver into a USB 2.0 port directly — not through a hub — and the pairing restores within a few seconds.

Mouse pointer stuttering or skipping before the battery warning appears

The MX Master's Bluetooth polling rate steps down automatically as cell voltage sags toward end of life, even before the low-battery LED triggers. This causes the pointer to stutter or skip on-screen — users often attribute it to surface or sensor issues first. The voltage sag is a normal end-of-life behaviour in this cell chemistry at 3.7V nominal. If the stutter clears immediately after a full charge cycle, the cell is degraded and replacement is the fix, not a driver update or surface change.