My UPS was beeping constantly (faster then the out of AC power beep). Disconnecting the battery - still beeped! Checked on the APC website and the device is discontinued. I took it apart thinking that maybe one of the internal fuses went. Nope. I then searched forums for tips and came up empty. Finally I just unplgged the thing and let it sit on the bench for a week or so. I then cam back an hooked a known good battery to the unit and plugged it. BAM! that fixed it. seems the battery really was dead but it would not recognize a NEW good battery until the unit sat and discharged completely ??? weird. Anyone else have similar or other experience like this ?