If you're seeing the event every day it is not due to the weekly battery test as it only takes place once a week. There is no way to select a daily test.  However, to check the testing time in the Navispher GUI expand the "Physical" array until you see the standby power supplies.  Right click on each unit and select "Set Test Time" (setting the time and date on one one will be automatically migrated to the other).   It will show you the current test time and day.  Is there a temperature problem in the computer environment?  There are temperature sensors in the power supply which could trigger it to shut down.  Do the errors occur close to the same time every day? Is there possibly something blocking the air flow to the power supply fans?   Are there fan faults being logged also?
I'm getting the below message on our CX-300 SAN but everything in Navisphere looks perfect. We've replaced both battery units and one of the power supplies but still get this message. Any ideas?   Time Stamp 03/30/10 11:48:10 Event Number 904 Severity Error Host CX30x01SPB Storage Array APM00000000000 SPB Device Enclosure 0 Power A Description VSC Shutdown/Removed  Thanks,  
Event number 904