Battery Life
Battery life is the rated operating or playback time from a full charge under stated conditions.
Runtime depends on the operating mode and test setup. It is separate from battery charge capacity, recharge time and standby duration.
Battery Life — Headphone
For headphones, runtime can differ with noise cancellation, wireless mode and playback conditions. A charging case may provide additional recharges but does not extend one uninterrupted charge of the earpieces.
Compare the same listening mode and distinguish earpiece runtime from the total including the case. Keep any volume or codec condition with the figure; a maximum claim need not describe every mode.
Battery Life — DAC
For a battery-powered DAC, runtime describes the available operating time in the specified connection and output mode. Supplying another device or using an integrated headphone output can change power demand.
Compare equivalent operating conditions and keep standalone battery operation separate from externally powered use. A charging or USB-power connection may alter the runtime arrangement rather than represent the same battery-only test.
Battery Life — Digital Audio Player
For a portable player, runtime can depend on file format, wireless use, display activity and headphone-output mode. The stated figure applies to the accompanying test conditions.
Compare the same output and playback mode rather than choosing only the largest advertised duration. Local playback and online streaming can have different results. Battery capacity in mAh is not a direct replacement for measured runtime.
Battery Life — Headphone Amp
For a battery-powered headphone amplifier, runtime depends on the load, listening output and selected operating mode. High-power operation can impose different demands from a lower-output setting.
Compare runtime under similar headphone and connection conditions. Do not substitute standby time or charging time, and keep operation while externally powered separate from the stated battery-only duration.