Hey, Bob,
How have you been setting the clock? Using the WB Prefs "Time" program in the Prefs drawer? That should be all you need.
Did you install the battery on the MB? Or hanging out on wires? Have you tested the voltage across the battery with a meter? Are you sure the battery isn't connected back to front (it can't be if it's soldered onto the MB)?
Where do you live?
tony