About this replacement
JBL Bar 5.1 — 3.7V Li-Polymer Replacement Battery (GSP872693)
This is a 3.7V, 3000mAh (11.1Wh) lithium-polymer cell that replaces the original GSP872693 battery in the JBL Bar 5.1 soundbar. It powers the detachable surround speakers that go wireless during Bar 5.1 operation. Swap it in when the original no longer holds a charge or cuts out mid-session.
- Bar 5.1 surround speaker compatibility: The detachable rear speakers on the Bar 5.1 each carry their own Li-Polymer cell. This 95 x 28.90 x 10.70mm pack matches the form factor and voltage rail the onboard BMS expects — no adapter, no rewiring.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Bar 5.1 platform. The BMS accepted the pack without error codes, balanced correctly, and held stable voltage across both low-volume and high-volume playback draws.
- Monthly discharge cycle for the Bar 5.1: These speakers often sit in the dock between uses and get topped off constantly. Let the surround speakers run down below 20% at least once a month before redocking — without periodic full discharges, the fuel gauge drifts and the BMS begins reporting false capacity.
Why the Bar 5.1 surrounds cut out during loud passages
At high volume, the Class D amplifier inside each surround speaker pulls a sharp current spike. An aged or degraded Li-Polymer cell cannot sustain voltage under that combined amplifier and wireless radio draw. The BMS interprets the resulting sag as an undervoltage fault and disconnects the cell to protect it. A fresh cell with full capacity holds voltage through those spikes and keeps audio uninterrupted.
Audio distorting before the battery indicator reaches empty
This happens when the cell's internal resistance has risen enough to cause voltage sag under load, even though resting voltage still reads normal to the indicator circuit. The amplifier clips because it is not receiving stable supply voltage — the sound distorts but the LED shows two or three bars remaining. Check resting voltage with a multimeter; a healthy 3.7V cell should read 3.9–4.1V after a full charge. If it reads below 3.7V at rest, the cell needs replacing.