JBL Live Pro 2 Charging Case Compatible Battery 3.7V 500mAh

JBL Live Pro 2 Charging Case — 3.7V Li-Polymer Replacement Battery (GSP721641)

This is a 3.7V, 500mAh Li-Polymer battery for the JBL Live Pro 2 Charging Case and Tune Flex Charging Case. It replaces the internal cell that powers the case's ability to store charge and top up your earbuds between AC connections. When this cell degrades, the case stops delivering full charge cycles to the earbuds — this battery restores that function.

• Live Pro 2 and Tune Flex case compatibility: Both cases use the same GSP721641 cell, same 3.7V rail, and the same charging IC on the case PCB. The connector pinout and physical dimensions match — 42.20 x 15.40 x 7.50mm — so no adapter or modification is needed.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Live Pro 2 case. The BMS accepted the pack without fault flags, and the case resumed earbud charging normally across multiple sessions.
• Case recalibration after replacement: After fitting the new cell, drain the case fully via earbud charging, then charge it back to 100% on USB-C before use. The case firmware recalculates its charge display based on this first full cycle — skipping it causes the LED indicator to misread remaining capacity.

Why the case LED shows full but the earbuds cut to low battery faster than expected

A worn or newly installed cell often sits at storage voltage — around 3.6–3.7V — which the case firmware reads as a near-full charge. Under actual earbud charging load, voltage drops quickly and the case depletes faster than the indicator suggests. This is not a fault with the replacement cell. One full drain-and-charge cycle lets the firmware recalibrate the state-of-charge curve against the new cell's actual capacity. After that first cycle, the LED indicator tracks remaining charge accurately.

Case not charging the earbuds at all after battery replacement

If the earbuds sit in the case but show no charge gain, the most common cause is an incomplete BMS handshake after installation — the case PCB did not complete its initialisation with the new cell. Remove the earbuds, connect the case to USB-C power for at least 30 minutes without the earbuds seated, then reinsert them. If the case still shows no output, check that the cell connector is fully seated — a partially connected ribbon can cause the PCB to detect a fault and disable the output rail entirely. Confirm the case wakes up by pressing the button; no LED response at all points to a connection issue rather than a cell fault.