CMOS Battery

Hi,
Does taking a CMOS battery out of a motherboard stop its energy drain.
I ask this because I have a second computer that is not used often.
Exactly how long is the CMOS battery lifespan?
Thanks.

 

The "practical" answer would be NO, all chemical batteries effectively start discharging after manufacturing. The CMOS circuitry actually places very little drain on the battery, most find that they last about three years. About as long as the recommended "Shelf Life" of the battery

 

True. And your mileage may vary. I've seen some CMOS batteries (especially the good old CR2032) last 5 years or more, but you wouldn't want to count on it.

BCGray is referring to the self-discharge rate inherent in all chemical batteries when he points out that "all chemical batteries effectively start discharging after manufacturing." Lithium cells (such as the CR2032) typically have a very low self-discharge rate, unlike some of the older Ni-Cd batteries which typically lose 10% of their charge per month just standing on the shelf.

However, the draw on the battery imposed by the CMOS chip is so low that the limiting factor on the battery's service life is determined by the battery's self-discharge rate as much as the service load.