Logitech Zone 533-000167 Replacement Battery 3.7V 400mAh

Logitech Zone / Zone 900 — 3.7V Li-Polymer Replacement Battery (533-000167)

This 3.7V, 400mAh Li-Polymer cell replaces the original battery in the Logitech Zone and Zone 900 wireless headsets. It matches OEM part numbers 533-000167 and 383040. Swap it in when the original cell has degraded and the headset no longer holds a charge through a full work session.

• Zone and Zone 900 compatibility: Both models run the same 3.7V cell with the same connector footprint and BMS handshake protocol. The shared power rail and physical dimensions — 42.50 × 30.10 × 4.80mm — mean one cell fits either variant without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on Zone hardware. The BMS accepted the pack without error flags, held voltage within the expected range under combined DECT radio and audio draw, and reached full charge cutoff correctly in the base station.
• First charge in the base station: Place the headset in its base station for one complete charge cycle before taking a call. The base station logs the new cell during this cycle, and the talk-time estimate shown on paired software will not read accurately until that first full cycle completes.

Base station showing full charge but headset cuts off after short use

A fresh replacement cell ships at storage voltage — typically around 3.6V — not at full charge. The base station LED can show green before the cell has actually completed a proper charge cycle. The BMS needs one full charge-to-cutoff pass to calibrate the charge state correctly. Put the headset in the cradle and leave it for a full cycle before use; after that, the base will report charge state accurately.

Headset cutting out mid-call after battery replacement

The Zone headset pulls current for both audio processing and the DECT radio simultaneously during a call. If the cell voltage sags under that combined load — common in the first few cycles before the Li-Polymer cell reaches full capacity — the BMS will trip the cutoff to protect the cell. This is not a fault with the battery. Run three to five full charge and discharge cycles and the voltage sag under load will reduce as the cell conditions. If cutouts continue past five cycles, check that the base station contacts are clean and making solid contact with the headset charging pins.