According to JBL, the Boombox is poised to last for 24 hours of playback for every charge. The claim stands true, especially if the volume is turned halfway up, played through a wired connection, or Bluetooth.
However, be careful not to let the battery on this JBL Boombox get below 20%. At this stage, you will notice a buzzing sound that can get annoying. There is nothing particular to explain the sound. Given the price tag on this speaker, the sound comes as a deterrence.
It can get you to reconsider purchasing the JBL Boombox. However, you may want to note that this issue is prominent only when the battery is below 20%. For any other level, it works very well and at a good volume.