Question replacement of CMOS battery

[wpshooter]

1) How much TIME (seconds or minutes) do you generally have to get the old CMOS battery out and replaced with a good new fresh
battery without completely loosing the BIOS ?

2) When I made this change recently, the settings were still there after I installed the new battery
however, the time and date had to be reset. Why does it loose the time and date settings and yet
the other BIOS settings are not lost ? Is there not a built up charge/reserve to the time clock ?

Thanks.

 

[RLGL]

1) How much TIME (seconds or minutes) do you generally have to get the old CMOS battery out and replaced with a good new fresh
battery without completely loosing the BIOS ?

2) When I made this change recently, the settings were still there after I installed the new battery
however, the time and date had to be reset. Why does it loose the time and date settings and yet
the other BIOS settings are not lost ? Is there not a built up charge/reserve to the time clock ?

Thanks.

The battery is what powers the storage of the time and date. To reset after removal and or replacement is normal. There is no alternate source of power for the storage function.

 

[kschendel]

I suppose that the BIOS could save the date and time to non-volatile memory, but there wouldn't be a lot of point to it. There would be no way to know how much time passed since the date and time was stored, so you'd have to reset the time anyway, and possibly the date.

 

[tcsenter]

It is very very very low number of seconds that you are unlikely to pull off without a lot of luck or investing much more time in practicing than it would have taken you to just re-enter all the BIOS settings as they were.

 

[Shmee]

Actually, if the board is connected to a PSU which is powered, I think the CMOS should retain power in most cases.

That said, do not mistake this for leaving a machine in the on state while working on it. I am simply saying have the PSU plugged in, but the computer should be off when you are working on it

 

[lenjack]

yup