CMOS battery
Motherboard Battery / CMOS battery - This battery on the motherboard is used to preserve the configuration memory (also called CMOS) and the computer clock.
Most manufacturers do not list the exact type and model of your CMOS battery. It is recommended that, once you have located the battery, write down all information about the battery (Voltage, chemistry, wiring, and packaging). If possible, remove the battery and take it to the retail location.
The battery type CR2032 button cell is the most common CMOS battery.
If your computer is using a coin cell battery, removing the battery is relatively simple. Use your fingers to grab on the edge of the battery and pull it up and out of the socket holding it in place. Some motherboards have a clip holding the battery down.
Other common battery cell types can last significantly longer or shorter periods, such as the smaller CR2016 which will generally last about 40% less time than CR2032. Higher temperatures and longer power-off time will shorten battery cell life. When replacing battery cell, the system time and CMOS BIOS settings may revert to default values. However, it is common for the battery to be dead prior to the user actively replacing the battery and thus all BIOS settings require entry.
Some computer systems may use other types of cell batteries such as the cylindrical "1/2 AA" used in the Power Mac G4. Visually inspect the motherboard to verify the type of battery being used before purchasing a replacement.
See also: