A:Answer The JBL Xtreme uses Lithium-Ion (Li-ion) polymer batteries. This type has high energy density, very low memory effect and low self-discharge. Batteries gradually self-discharge, even if they are not connected to anything. Usually, you can expect a self-discharge of about 2% per month when the battery is new, and this may increase somewhat with battery age and temperature. In other words, it will depend upon the usage of the speaker.