GSP981642 JBL TUNE Beam Charging Base Compatible Battery 3.7V 750mAh

JBL TUNE Beam Charging Base — 3.7V Li-Polymer Replacement Battery (GSP981642)

This 3.7V, 750mAh Li-Polymer battery replaces the internal cell in the JBL TUNE Beam Charging Base. It fits the dock that wirelessly charges the TUNE Beam headphones. When the base battery degrades, the dock can no longer hold a charge between headset top-ups — this cell restores that function.

• TUNE Beam Charging Base fitment: The GSP981642 cell runs the dock's internal power reserve, which the base draws from to charge the headset when the dock itself is unplugged. Voltage rail, connector pitch, and BMS communication all match the original pack specification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the base station circuit. The BMS accepted the pack without error flags, and charge-pass-through to the headset initiated correctly across both plugged and unplugged dock modes.
• First-cycle base registration: After fitting this cell, keep the base connected to USB power for one full charge cycle before using it unplugged. The base logs the new cell's capacity on that first cycle — without it, the dock's charge indicator will read inaccurately.

Base station not recognising the new pack after installation

The TUNE Beam base uses a BMS handshake to verify the internal cell before enabling charge output to the headset. If the cell arrives at storage voltage — typically around 3.6V to 3.65V — the base may show no charge activity or flash an error LED. Connect the base to USB power immediately after fitting the new cell and leave it undisturbed for a full charge cycle. Once the BMS completes its initialisation at full voltage, charge pass-through to the headset resumes normally.

Headset cuts out mid-call after base battery replacement

Mid-call dropout on a freshly installed cell usually points to voltage sag under combined DECT radio and audio draw. A cell in its first few cycles has not yet reached full electrochemical capacity, so internal resistance is higher than rated — the voltage dips under load and the headset drops the connection. This is not a fault with the replacement cell. Run three to five full charge-discharge cycles through the base and headset together, and the sag will reduce as the cell conditions. Check that the headset reads at least 3.8V resting before the next call.