Sony BSP60 Replacement Battery 3.7V 2050mAh BA950

Sony BSP60 — 3.7V Li-ion Replacement Battery (BA950)

This is a 3.7V, 2050mAh (7.59Wh) Li-ion battery for the Sony BSP60 portable Bluetooth speaker. It slots directly into the BSP60's internal battery bay and connects to the same charge controller and fuel gauge circuit as the original BA950 cell. If your BSP60 won't hold a charge or cuts out during playback, this is the cell to replace.

• BSP60 fit and electrical match: The BSP60 uses a single-cell Li-ion pack at 3.7V nominal — that voltage rail feeds both the amplifier board and the Bluetooth radio. A mismatched voltage or wrong connector pinout throws off the fuel gauge and can trigger a premature BMS shutdown. This cell matches the BA950 footprint, pin layout, and voltage spec so the charge controller reads state-of-charge correctly.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the BSP60 platform and monitored BMS communication. The protection circuit responded correctly to charge termination, over-discharge cutoff, and current spikes from the amplifier during high-volume bursts.
• Fuel gauge reset after install: After fitting the new cell, run the BSP60 from full charge down to auto-shutoff before recharging. The BSP60's fuel gauge recalibrates on a full cycle — skipping this step causes the charge indicator to misread remaining capacity from the first week of use.

Why the BSP60 shuts down during high-volume playback

At high volume, the BSP60's Class D amplifier pulls sharp current spikes that a degraded or partially discharged cell can't sustain. The BMS reads that instantaneous voltage sag as an under-voltage fault and cuts output to protect the cell. A new cell with healthy internal resistance handles those peaks without the voltage rail dropping below the BMS cutoff threshold. If the problem appeared gradually over months of use, cell degradation — not the amplifier — is almost always the cause.

Audio distorting before the battery indicator reaches empty

This happens when the cell's internal resistance has risen enough that voltage sags under load even while the fuel gauge still shows charge remaining. The amplifier clips because the supply rail can't hold steady voltage during loud passages — it's not a speaker driver fault. The fuel gauge reads open-circuit voltage, which looks acceptable, but under the actual current draw of the amplifier the cell is already struggling. Replacing the BA950 cell and completing one full discharge cycle to recalibrate the gauge resolves both the distortion and the inaccurate indicator.