I bought a CyberPower UPS rated at about 1500 VA/900 W because my neighborhood regularly experiences brownouts lasting several hours. It worked normally at first, but it began shutting down unexpectedly well before I expected.
My PC and two monitors draw only around 140 watts when idle, yet the UPS has shut off twice this week. During one brownout, it began beeping as if the battery were nearly empty and then powered down. When utility power returned about 10 minutes later, the charging indicator blinked briefly before showing the battery as fully charged.
The other shutdown happened without an apparent brownout. The monitoring software showed the battery charging, stopping, and then immediately reporting 100% capacity. I also noticed several earlier periods where the UPS lost its connection to the computer.
As a test, I unplugged the UPS while the PC was running. The software reported the battery capacity dropping from 100% to 12% and then 0%, but the UPS did not shut down immediately; it only emitted continuous warning beeps. Could the battery or UPS electronics be defective, or is there something I may have configured incorrectly? Should I request a warranty replacement?
1 Answer
The battery is the most likely problem. A UPS can still report 100% shortly after charging if the battery has lost most of its usable capacity; the voltage rises quickly, but it collapses as soon as there is a real load or outage. That would explain the sudden shutdowns even with only about 140 watts connected. Check the battery date and warranty terms, then contact the manufacturer for an RMA. If the battery is considered a consumable and is no longer covered, it will probably need to be replaced.
That is frustrating—I saved for this unit for about a month, and it did not even make it a full year. I am going to start the warranty process.