Philips GoGear Muse BA504457SP Replacement Battery 3.7V 1400mAh

Philips GoGear Muse — 3.7V Li-Polymer Replacement Battery (BA504457SP)

This 3.7V, 1400mAh lithium-polymer cell replaces the BA504457SP battery in the Philips GoGear Muse portable media player. It fits models SA2MUS16S/02 and SA3MUS08S/37. Dimensions are 56.45 × 44.10 × 5.00mm — measure your original cell before ordering if you are unsure.

• GoGear Muse SA2 and SA3 compatibility: Both SA2MUS16S/02 and SA3MUS08S/37 variants use the same BA504457SP cell with identical voltage rail, connector pinout, and BMS handshake. One cell covers the full Muse range listed above.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a GoGear Muse unit. The BMS accepted the cell without fault flags, and the charge circuit ramped current normally through CC and CV phases.
• Post-swap charge protocol for the GoGear Muse: After fitting a new cell, connect the Muse to its charger before powering it on. Media players in this class often enter deep-discharge protection during long storage. A 30-minute trickle from the charger clears that state before the device accepts full current.

Battery percentage jumping after a cell swap on the GoGear Muse

The GoGear Muse reads battery level by comparing cell voltage against fixed thresholds in firmware. A brand-new cell has a slightly different voltage curve than the aged cell it replaced, so the indicator recalibrates over the first few charge cycles. You may see the percentage jump from 80% to 100% or drop suddenly near the end. Run two or three full charge-to-discharge cycles and the readings stabilise as the firmware maps the new cell's curve.

Playback cutting out before the battery indicator shows empty

The audio amplifier inside the Muse draws a brief current spike every time it drives headphone output at higher volumes. Near end-of-charge, the cell voltage sags under that spike and can briefly dip below the BMS cutoff threshold — killing playback even though the indicator still shows charge remaining. This is a voltage-sag issue, not a capacity issue. If playback cuts at moderate volume near end of charge, reduce output volume by 20–30% to lower amplifier draw and get the cell past that sag point.