When the console's main power source is removed or exhausted, the button battery provides a weak, continuous power to a special memory chip on the motherboard. This chip is responsible for storing key information such as your game progress, settings, time and date. Without this button battery, once the main power is disconnected, your saves will be lost. Maintaining the real-time clock: Some newer or special-purpose game consoles have a built-in real-time clock. The button battery is responsible for maintaining the clock when the main power is disconnected, ensuring that the in-game clock system (such as the day and night cycle or event triggering in some games) remains accurate after the console is turned on.