About this replacement
JBL Live 660 / Live 660NC — 3.7V Li-Polymer Replacement Battery (GSP683331)
This is a 3.7V, 750mAh Li-Polymer replacement cell for the JBL Live 660 and Live 660NC wireless headphones. It fits directly into the headset housing and uses the same connector and BMS interface as the original GSP683331 pack. Swap it in when the existing cell no longer holds enough charge to get through a listening session or call.
- Live 660 and 660NC compatibility: Both models share the same 3.7V cell architecture, connector pinout, and BMS handshake protocol — that is why one part number covers the full range. The 660NC adds active noise cancellation, which draws on the same cell alongside the audio and Bluetooth radio.
- Bench tested on actual hardware: We ran the GSP683331 cell through charge and discharge cycles on the Live 660 platform. The BMS accepted the new pack without fault codes, charge current ramped normally, and the protection circuit tripped correctly at low-voltage cutoff.
- First charge after installation: Seat the headset in its charging cradle and let it complete a full charge cycle before use. The JBL Live 660 firmware recalibrates its fuel gauge against the new cell during that first cycle — skipping it causes the battery indicator to read inaccurately for the first several uses.
Why the Live 660NC drains faster than the Live 660 on the same replacement cell
The 660NC runs three loads simultaneously: Bluetooth audio, the DSP, and the ANC microphone array. That combined draw is meaningfully higher than the standard 660. A 750mAh cell is the correct spec for both — it matches the original — but users upgrading from a standard 660 to an NC unit sometimes expect identical endurance. The ANC circuit alone adds a sustained parasitic draw that was not present in the base model. If endurance seems short on the NC variant, verify ANC is not left on when not needed.
Battery indicator shows full but headset cuts off after a few songs
This happens when a replacement cell arrives at storage voltage — roughly 3.85V — and the headset firmware mistakes that resting voltage for a full charge. The fuel gauge has not yet mapped the cell's actual capacity. One complete charge-to-discharge cycle corrects the calibration. After that cycle, charge the headset fully to 4.2V before the next session and the indicator will track accurately.