I ran an A4000 without a battery for serveral years and it worked fine, I just put the "Time" preferences program in my WBStartup drawer. So you shouldn't have any problems. As others have said, just take care not to cause any damage when removing it.
If your A4000 has a rev. D motherboard with a Lithium coin cell there should be no need to remove it as this type don't leak like the barrel shaped NiCds.
Robert
