Bose SoundLink Replacement Battery 11.1V 4500mAh Li-ion

Bose SoundLink Series — 11.1V Li-ion Replacement Battery (084951)

This is an 11.1V, 4500mAh (49.95Wh) Li-ion battery for Bose SoundLink portable Bluetooth speakers. It replaces OEM part numbers 084951 and 882355-0010. If your SoundLink no longer holds a charge or shuts off unexpectedly during playback, this battery fits the slot directly.

• SoundLink series compatibility: These Bose speakers share a common 11.1V three-cell Li-ion pack format with a matching BMS handshake. The connector pinout and cell configuration are consistent across this speaker line, so the BMS communicates correctly with the speaker's charge controller without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on SoundLink hardware. The BMS engaged protection cutoff correctly at the low-voltage threshold, and charge termination triggered cleanly at full capacity without overcharge.
• Monthly discharge cycle for SoundLink users: These speakers are often left on a desk plugged in continuously. Let the battery drain below 20% at least once a month before recharging — constant top-off charging without a full discharge causes fuel gauge drift and accelerates capacity fade on the Li-ion cells.

Audio distortion before the battery indicator reaches empty

As a Li-ion pack ages, internal resistance rises. At moderate to high volume, the amplifier draws a spike of current that causes the cell voltage to sag below what the amp needs to run cleanly. The speaker clips the audio signal before the battery gauge reads empty because the gauge tracks average voltage, not instantaneous sag. A fresh pack with lower internal resistance eliminates this — cell voltage holds above 10.5V under load where the old pack was dipping below that threshold.

Bluetooth drops at high volume on an otherwise-healthy battery

The amplifier and Bluetooth radio both draw from the same cell pack simultaneously. At high volume, the amplifier current surge combines with the radio's transmit draw, briefly pulling total load high enough to trigger the BMS undervoltage cutoff or cause a momentary voltage dip that resets the radio stack. This is more common on a degraded pack but can also appear on a new battery if the cells are cold — below 10°C, Li-ion internal resistance spikes sharply. Warm the speaker to room temperature first, then confirm the symptom disappears before replacing the pack.