After many horror stories with APC UPSes: - failed battery caused APC to stop operating even with power (just as in the original post) - stopped charging batt

After many horror stories with APC UPSes: - failed battery caused APC to stop operating even with power (just as in the original post) - stopped charging battery even though battery was still good (blow electrolytic cap. When I into the circuit that capacitor was rated for 14V on a 12V trace, ie no guard-band. Seriously, skimping on maybe $0.01 total parts cost to leave a system at risk of fire??? Who the heck signed on on that decision???) - couple of data center APC UPSes caught fire. On the plus side the emergency systems kicked in quickly enough that the only damage were the UPSes. Anyway, that was a few too many stupid failures. APC is on my "never ever buying from this company ever again" list.