JBL Xtreme Li-ion Battery Mod - The Right Way - YouTube
Jbl Xtreme battery upgrade to 18650 cells - YouTube
Z074] 7.2V 5200mAh/37.44Wh [186502S2P] Lithium Ion Battery for Bluetooth Audio Speaker JBL XTREME 2 SUN INTE 103 2INR19/66 2|Replacement Batteries| - AliExpress