I install and service UPS systems from 1.5kVa to 1.500kVa.
Get a new battery. The UPS may show some runtime but it is wrong. Inputs to a UPS can vary up to 10%.
A sag or swell phase to phase will force battery operation then your load drops. Battery is dead and UPS turns off.
Yes your UPS is a line conditioner at all times as the input is being re-created by the inverter.
You have a VRLA battery that needs replaced every 3 years.
Or get a better UPS. Always a chance your UPS itself is faulty. The small UPS’s do not hold up well after 5 years IMHO.
# A sag or swell phase to phase will force battery operation then your load drops. Battery is dead and UPS turns off.
I get that, but if I can kill power to the UPS by unplugging it, and it works as expected, doesn’t that mean the battery is OK, or at least not bad enough handle a small outage?
“A sag or swell phase to phase will force battery operation then your load drops. Battery is dead and UPS turns off.”
He says his battery works fine when power is lost.