Computers typically rely on a PSU (Power Supply Unit), which uses switching technology and low-voltage DC power, as a main power source. Most computers also contain an independent battery. A computer battery plays a crucial, time-related role in a PC's operations.
A computer battery is typically a lithium-type battery that is directly soldered to the motherboard, or primary circuit board of a computer.
The computer battery powers an integrated chip called an RTC, or real-time clock. The RTC is basically a small, quartz clock, and allows the main computer system to perform time-critical tasks. The real-time clock tracks the current time, and runs whether the computer system is on or off. When a computer boots, part of its start-up process is to send a query to the RTC to determine the date and time.
A typical lithium computer battery can run from two to 10 years. Some factors that affect the lifespan of a computer battery include ambient temperature, the duration of time the computer is powered off, and the type of motherboard the battery is attached to.