Why the bios CMOS battery is important to change

[bigpup]

The computer uses a CMOS battery, to keep the memory chip that stores UEFI/Bios settings, constantly powered.
This memory is type that will only retain stuff when powered.

I was trying to boot into Fossapup64 9.5 on a very new computer.
This computer is a little over 1 year old.

When I started the computer. It did not go to the normal UEFI bios boot screen logo and than to the normal boot loader menu.
All it would do is activate the keyboard and stop at nothing on the monitor.
Fans were running.
Internal lighting was on. (fancy gaming motherboard with lights)

It stayed in this no response state for about 5 minutes, when all of a sudden the boot loader menu showed on monitor.
So, something was not correct about the UEFI bios startup.

First thing I did was replace the Bios CMOS battery, with a new one.

Next boot was normal.

Did have to go into the UEFI setup and make sure all was properly setup.
I was basically using default settings anyway, so not much needed adjusted.

I did a voltage check on the old battery.
It read around 1.0 volt DC.
Normal voltage is 3 volts DC.

I think the strange booting was caused by the battery not being completely dead.
It had just enough voltage to make the bios think it was good, but not enough to make it do a normal boot.
Eventually it went to using default CMOS settings and finally booted.

A failed CMOS battery will cause the following problems:

Code: Select all

The computer will give an incorrect date and time.
BIOS passwords will be reset.
Some drivers may be missing or may not work properly.
The computer will throw a boot error.
You may not be able to visit certain websites or access services due to the wrong date and time.
You may hear a constant beeping sound, indicating a low or dead CMOS battery.
Sometimes, computer peripherals like the keyboard or mouse fail or malfunction when the CMOS battery is dead.[/quote]

These batteries should be good for around 4 to 7 years.
Nothing is in stone, if there is a defect in the battery.

Update:
On very, very, new computers, the CMOS memory is now the type that does not need constant power, to retain what is stored in it.
Same type memory used in a SSD or USB stick drive.

However, they do still have a CR2032 disk battery, to keep the internal clock powered at all times, so it will always have correct time.
.
.

[p310don]

I have recently acquired a couple of old throwaway laptops that would no longer boot. Both of them have no CMOS battery, instead relying on the laptop battery to provide that power. Both machines have "non-replaceable" batteries, so no CMOS, no boot. Previous owners have new computers now, after a few years.

Anyway, I replaced the non-replaceable batteries and I have two great Fatdog laptops

[BarryK]

bigpup,
That is very interesting, as a few days ago I had the same problem!

I purchased my Lenovo Ideacentre 510S desktop PC in March 2020. A few days ago, got back from a camping trip, turned on the PC and it made a loud sound, like the fan was running extra fast. Then became quiet for a few seconds, then booted as normal -- except the hardware clock was set to January 2017.

Every time powered up the PC, same problem, loud initial sound, pause, then bootup with cmos clock reverted to Jan. 2017.

This morning I bought a new battery, 3v lithium cr2032, and now OK.

Interesting that the user manual states the battery should last for the lifetime of the computer.

[mikewalsh]

@BarryK :-

bigpup,
That is very interesting, as a few days ago I had the same problem!

I purchased my Lenovo Ideacentre 510S desktop PC in March 2020. A few days ago, got back from a camping trip, turned on the PC and it made a loud sound, like the fan was running extra fast. Then became quiet for a few seconds, then booted as normal -- except the hardware clock was set to January 2017.

Every time powered up the PC, same problem, loud initial sound, pause, then bootup with cmos clock reverted to Jan. 2017.

This morning I bought a new battery, 3v lithium cr2032, and now OK.

Interesting that the user manual states the battery should last for the lifetime of the computer.

That's the industry talking, Barry. A 4-7 yr life span IS now regarded as being "for the life of the computer"; these days, owners are positively encouraged to trade up every 2-3 years, so the industry doesn't expect anyone to be daft enough to be running 15 yr-old+ hardware..!

Long gone are the days of trying to build yourself a reputation. Now, the consumer is simply regarded as an expendable commodity, purely for the benefit of manufacturers.....hence the existence of equipment that is built to fail after a certain period of time. Because it guarantees your having to keep going back to buy again, and again, and again.....

(You've heard of "planned obsolescence", yes? That's it in a nutshell, right there.)

My old Compaq rig was almost 16 yrs old when it finally popped its clogs. I've had this replacement HP midi-tower for around 2; I'd like to think it'll make it to at least its 10th birthday, but I just don't have the confidence in modern equipment these days.....

Mike.