Back-UPS RS 1500G display issue after battery replacement

[Anonymous user]

The battery in my Back-UPS Pro 1500 failed after 5 years of service, so I ordered a new OEM replacement (it's a full APC battery, not some 3rd party junk).  I replaced the battery, and now the UPS is displaying ONLINE with about a 25% load, and the "Battery Charge" indicator is flashing, with zero bars filled.  It's been like that for several hours.  The audible alarm is doing two quick beeps in succession, repeatedly.

The manual gives no information on such a display.  What does it mean?

Thanks,

J.

Edit:  Pulling the plug causes it to behave as if it has no battery at all - just drops dead.  Computer OS (Mac) reports the model number correctly, but says "100% charge" on status window.  

[Anonymous user · Accepted solution]

Never mind.  Someone thought it would be hilarious to swap the old battery for the new one in the box while I was in the restroom.  48 hours wasted.  Finally checked the serial numbers.  LOL.  

J.