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Notebook computer's CMOS battery

Cheng Luo

Notebook computer's CMOS battery

I am not a computer expert, I just heard there is another battery, which is for CMOS (but I dont know what is CMOS)in Notebook computer. and I heard this battery can last for 3 years normally. My Notebook is more than 2 years now, It is very nice, it has been most important tool for me. Does someone could introduce a lilttle bit this kind of battery, what will happen if such battery used up.

Thank you very much!
Michael Elleby III_1
Trusted Contributor

Re: Notebook computer's CMOS battery


The battery that supports the CMOS chip in your computer maintains the current hardware configuration of your machine (i.e. type of hard disk, # of cylinders, heads, sectors, amount of memory, system date, etc.) In order for this info to be maintained on the chip after you have unplugged the machine from a wall source, this battery must be present and in good condition.

If it goes bad (used up), you'll find yourself inputting the info I mentioned above every time you power the machine on. So basically you'll need to have a qualified technician install a new battery. In some cases on some manufacturer's laptops, you may be able to do it yourself.

Hope this helps.

Mike E.
Knowledge Is Power