# 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?
Yes it does. If the battery holds after unplugging the UPS your UPS has a problem.
125Vac input is not a problem.
After that tidbit of information I’m not sure what your issue is. What load % is on this?
Keep Printers off of it BTW. Inductive loads will overload if it goes above 105% on battery.
Also make sure the output receptacles are all battery backup.