CMOS Battery Question

F1aw1ess · 6 Dec 2018 at 10:03

I have a laptop that loses its date and time if the laptop isnt plugged into the mains at all time.

I know the CMOS battery is dead but I literally have to take the laptop to bits to get at it.

My questions is; as the normal laptop battery is also dead and it has to be in the mains at all time, if I bought a new main laptop battery, providing that didnt completely run out of charge would the laptop hold its date and time off the main battery?

This would be a quick and easier fix if it would hold the date and time off the main battery as I can just disconnect the old dead battery and pop the new one in plus it means i could disconnect the mains when i wanted to.

Thanks

SamyBoy13 · 6 Dec 2018 at 11:23

Unfortunately, CMOS battery and laptop battery is completly different and not linked to each other. Thus if BIOS/UEFI loses time and date CMOS battery needs to be replaced. Does CMOS battery affect your pc in any way? I had dead CMOS battery in my old dell pc which would go into boot loop when battery was dead or not insitu so if your pc is fine I wouldnt bother replacing it.

EDIT
Just my opinion but Im lazy and time limited when it comes to opening up laptops

Also if you replace the normal battery it will hold date + time but if the battery is fully discharged it will forget it regardless. But only will hold date+ time if you put your computer into hibernation/sleep not full shutdown

F1aw1ess · 6 Dec 2018 at 11:32

Thanks for the reply but it seems to contradict itself, you initially say the cmos and main battery are not linked to eachother but then at the end you say if i replace the normal battery it will hold date and time unless fully discharged?

if i can just replace the main battery and ensure the battery doesnt fully discharge and it will hold the time and date then im happy with that.

Sorry if im reading it incorrectly

SamyBoy13 · 6 Dec 2018 at 11:40

It is likely me as I came after a nightshift and cant go to sleep. This is only if you set the time and date and dont let the pc discharge nor shutdown - so in theory it should be just like the laptop was on main power all the time. It is a temporarary-ish fix but I would just change the cmos battery when you have time