Shure RMCE-BT2 Replacement Battery 3.7V 180mAh Li-Polymer

Shure RMCE-BT2 — 3.7V Li-Polymer Replacement Battery (AEC501730)

This 3.7V, 180mAh lithium-polymer cell replaces the OEM battery in the Shure RMCE-BT2 Bluetooth earphone module. It restores wireless audio and Bluetooth connectivity when the original cell has degraded. Capacity matches the AEC501730 specification at 0.67Wh.

• RMCE-BT2 module compatibility: The RMCE-BT2 runs a combined Bluetooth radio and audio driver circuit on a single 3.7V rail. Both draw from the same cell simultaneously, so the BMS must tolerate the brief current spike when the Bluetooth stack initialises at power-on alongside the audio codec. This cell matches that voltage rail and connector footprint exactly.
• Bench tested on actual hardware: We cycled this cell through power-on and Bluetooth pairing sequences on the RMCE-BT2. The BMS accepted the new cell without a handshake error, and the module completed pairing without voltage dropout during radio initialisation.
• First-charge protocol for the RMCE-BT2: Connect the module to its charging cable and allow it to complete a full uninterrupted charge before the first pairing session. The RMCE-BT2 calibrates its battery indicator against the first full charge cycle — skipping this leaves the capacity gauge inaccurate from day one.

Why the RMCE-BT2 cuts out mid-audio on a freshly charged cell

The RMCE-BT2 draws from the battery for both the Bluetooth radio and the audio driver at the same time. During high-bitrate audio or codec negotiation, the combined current pull can spike briefly above what a partially conditioned or storage-voltage cell can deliver cleanly. The BMS interprets this as an undervoltage event and disconnects the output to protect the cell. Running two or three full charge-discharge cycles brings the cell to its rated delivery capacity and the cutouts stop.

RMCE-BT2 showing full charge but going silent after a few tracks

This happens when the module's charge indicator was never properly calibrated to the new cell. If the first charge cycle was interrupted or the module was used before reaching 100%, the fuel gauge anchors itself to a false full-charge reference point. The cell still has charge left when the module shuts down — the gauge is simply wrong. Fix it by charging the RMCE-BT2 uninterrupted to full (the indicator LED holds solid), then fully discharging through normal use before the next charge. After two cycles the read-out stabilises.