Today I got message “CMOS battery fail. BIOS defaults set.” when starting system which is about 2 years old. Is this likely a bad battery as it seems, or could it be possible mobo problem? In older systems I’ve had the battery would get weak gradually and lose 3 or 4 hours over night, but I’ve never had this type error before. No time loss was evident before this happened, but time, data and all BIOS settings had to be reset. Also batteries have always lasted 5 years or longer in my other systems. Is it possible for a battery to fail suddenly without symptoms it’s getting weak first?
It could be a battery failure, but as you say, 2 years is a relatively
short life for a lithium cell. I suppose the mainboard or lithium cell
could have been in storage for some time before you bought it.
Some ECS mainboards are prone to this problem. About once in
every 100 reboots, my old ECS K7S5A based PC will lose it’s
CMOS settings. I just set the time and date and carry on as
normal until the next time it happens.
Check the battery voltage in the bios setup or preferably
with a voltmeter. If all else fails, you will have to break
out and buy a new cell. If it is an ordinary CR2032 type,
it won’t cost more than a few bucks.
Try rebooting the machine and seeing if the message goes away. If it does, then the problem is probably resolved as long as it does not return.
Replace the CMOS battery. If this does not solve the problem, troubleshoot the motherboard.
Usually if the CMOS battery is gone your date and time will not remain current, and any changes that you have made to enable features in the BIOS will revert to their default values.
These batteries typically will last about three years, but how long was that one sitting around before you bought the computer.
Exactly, just as stated in my initial post, systems usually lose several hours of time over night but not this time. I’ve never had a battery last less than 5 years before while many have gone 8 years or so before needing replacement. However, battery replacement fixed the problem which seems to indicate either old battery or poor quality battery supplied with mobo.