A method includes determining a first voltage level of a first battery and a second voltage level of a second battery. Based on a difference between the first voltage level and the second voltage level satisfying a first threshold and a magnitude of a current failing to satisfy a second threshold, one of the first battery or the second battery is disconnected from the one or more components, and the one or more components of the portable device are powered using the other of the first battery or the second battery. Based on one or more of the difference between the first voltage level and the second voltage level failing to satisfy the first threshold or the magnitude of the current failing to satisfy the second threshold, the one or more components of the portable device are powered using the first battery and the second battery.