My reply is at the bottom of your sent message:

No, not really. Usually the symptoms for battery failure are the PC losing
time when it's powered off and then resetting to default time from the BIOS
settings. What you're showing/saying/seeing is more likely a problem due to
the RTC (real time chip) function of the BIOS itself or a separate chip
depending on the make, model, and age. I suppose it could be due to improper
voltage as well. It's a moot point really. The fix is complex, expensive,
and if it's a separate chip then it requires lots of gear to remove it from
the board and solder in a new one. Grab a time sync utility and don't worry
about it is really my actual advice in this case. You can try changing the
battery but if it's not failed completely while the power is off it's
unlikely that it is actually a CMOS battery failure. Even low voltage is
enough to keep the time in memory, when they fail they tend to fail all at
once.

Time Synchronization:
http://www.snapfiles.com/freeware/network/fwtimesync.html

Galen