Apparatus using battery and method of detecting exchange or recharge time of battery thereof

An apparatus using a battery and a method for detecting the exchange or recharge time of the battery are provided to inform the accurate exchange or recharging time even the intrinsic voltage of the battery is changed. An apparatus using a battery includes a battery(30), a function unit(32'), a voltage distributor(34'), an analog/digital converter(36'), and a controlling unit(38'). The battery supplies battery voltage(VBB). The function unit receives the battery voltage and performs intrinsic functions. The voltage distributor distributes the battery voltage, and generates distributed voltage(Vsen). The analog/digital converter receives the battery voltage, and converts the distributed voltage to a digital voltage signal(Vadc). The controlling unit receives the battery voltage, and informs the information about the remaining power of the battery by using the digital voltage signals applied at more than two different points of time.