Sony LSPX-S2 Replacement Battery 7.4V 3000mAh Li-ion

Sony LSPX-S2 / LSPX-S3 — 7.4V Li-ion Replacement Battery (9-301-005-96)

This is a 7.4V 3000mAh Li-ion replacement battery for the Sony LSPX-S2 and LSPX-S3 portable wireless speakers. It matches OEM part number 9-301-005-96 and fits the compact cylindrical housing used across both speaker generations. Capacity is 3000mAh (22.2Wh) — taken directly from product data, not estimated.

• LSPX-S2 and LSPX-S3 compatibility: Both speakers share the same internal battery bay dimensions, connector pinout, and BMS communication protocol. The 69.00 × 38.60 × 20.00mm cell drops into either unit without modification, and the BMS handshake clears on first charge on both models.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the LSPX-S2 platform. The BMS initialised cleanly, the fuel gauge reported correctly within two full cycles, and no thermal flags triggered during sustained audio output at high volume.
• Monthly discharge cycle for LSPX-S2 / LSPX-S3 users: These speakers are often left docked or topped off daily. Constant shallow charging without a full discharge causes fuel gauge drift and accelerates capacity fade. Run the speaker down below 20% at least once a month before recharging to keep the cell calibration accurate.

Audio distortion before the battery indicator reaches empty on the LSPX-S2

As the Li-ion cell ages, internal resistance rises. Under the combined current draw of the amplifier and Bluetooth radio, terminal voltage sags faster than the fuel gauge can track. The amplifier hits its minimum operating voltage while the indicator still shows one or two bars remaining. At that point the amp clips the signal rather than shut down cleanly, which produces the distortion. A fresh cell with lower internal resistance keeps terminal voltage above the amplifier's minimum threshold for a longer portion of the discharge curve.

LSPX-S2 not waking from USB-C charging after sitting unused for weeks

If the speaker sits discharged for an extended period, the cell can drop below the USB-C PD minimum acceptance voltage — typically around 2.5V per cell, or roughly 5V at pack level for a 7.4V 2S configuration. At that voltage the charger's PD negotiation fails because the BMS won't assert a valid handshake. Connect the speaker to a 5V 500mA USB-A source instead of a USB-C PD charger — the lower voltage and current allow a slow trickle recovery without triggering a PD rejection. Leave it connected for 20–30 minutes, then switch back to the standard charger once the pack recovers to 6V.