I chased a high-pitched buzzer/alarm in the CH electronics room to a dead UPS at the rear-top of rack CH01800 (Figure 1). That UPS has adaql10 plugged into its surge-suppressed outlets (which were still powered, but are not battery backed).
There was one cable plugged into a (dead) 'battery backed' outlet. This was traced to the thin 'tray' with a single power lamp and the DSM - DAPNIA label in the middle of the frame in Figure 2. Maybe this is a fan tray for the electronics immediately above it? Anyway, it had been off. I moved the plug to the rack's power strip and verified the power lamp turned back on. I am guessing that it might have something to do with the ARC energy system based on the sign underneight the tray (hence cc'ing Arun).