Microsoft LifeChat ZX-6000 Replacement Battery 3.7V 180mAh

Microsoft LifeChat ZX-6000 — 3.7V Li-Polymer Replacement Battery (X808059-003)

This 3.7V, 180mAh Li-Polymer cell is a direct replacement for the internal battery in the Microsoft LifeChat ZX-6000 wireless headset. It fits the headset's compact 30 x 20 x 4mm battery bay and restores wireless audio and DECT radio function when the original cell has degraded. Capacity is 180mAh (0.67Wh), matching the OEM specification.

• LifeChat ZX-6000 fit: The ZX-6000 uses a single Li-Polymer cell at 3.7V nominal to power both the audio driver and the DECT radio simultaneously. Any replacement must match this voltage exactly — feeding a higher-voltage cell trips the headset's onboard protection circuit and prevents pairing with the base station.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the ZX-6000 platform, confirming the BMS accepted the pack without a charging fault. The protection circuit engaged correctly at low-voltage cutoff and released cleanly on re-seat in the base station.
• First-cycle base station conditioning: Place the headset in the base station and allow a complete uninterrupted charge cycle before your first call. The ZX-6000 base logs the new cell during this cycle — skipping it causes the talk-time indicator to read inaccurately for several sessions.

Why the ZX-6000 cuts out mid-call on a new battery

The ZX-6000 draws current from one small cell to run both the speaker and the DECT radio at the same time. On a cell that has not completed its first full charge cycle, internal resistance is still elevated — combined audio and radio draw creates a brief voltage sag that the BMS reads as low-battery cutoff. The headset then drops the call and returns to the base. A full conditioning cycle in the base station before first use reduces internal resistance enough that the cell handles the combined draw without sagging below the cutoff threshold.

Base station showing full charge but headset shuts off after a few minutes

A new Li-Polymer cell ships at storage voltage — typically around 3.6V — not at full charge. If the base station reads this as a full pack and stops charging early, the headset starts each session with less capacity than indicated. The fix is to let the headset sit in the base for a full uninterrupted charge cycle of at least 3 hours without removing it. After that cycle, the cell voltage should reach approximately 4.2V and the base station talk-time estimate will stabilise.