【Stand-by function】 No playback and operation means the BTR3K is in stand-by mode after connecting. When there is no connection, it would automatically turn off after about 2min(you can choose the working time in the APP's settings). Its battery life is about 300 hours in idle status. 【Battery life】 With a built-in li-polymer battery, its battery capacity is 330mAh. Under low gains mode in AAC codec, it can continue to work for 11hours with merely 1.5-hour charging time. LDAC priority would allow a battery life for about 8 hours ; LDAC standard for about 9 hours; LDAC connection priority for about 11 hours; aptX for about 9 hours.