This was originally posted on APC forums on 2/7/2016
I have a 700 series APC power supply, with PowerChute software.
I'm in Thailand where no buildings or appliances have a ground wire (this might be a factor?).
The 220 supply here fluctuates wildly. It's a tourist area and when they get in from the beach and run their aircon and hot water between 4 pm and midnight, the 220v can drop to a steady band that's between 160v - 190v.
But this isn't the big problem. The UPS keeps clicking constantly - but doesn't kick-in with battery backup as these fluctuations are rapid and short-lived.
HOWEVER, I depend on a illuminated USB programmable keyboard. Every minute or so there's a TICK from the UPS, my keyboard stops responding and the lights on the keys go out. After a CLUNK - 20-30 seconds later, the keyboard is working again.
It's really infuriating. I depend on this keyboard as all my browser short-cuts are on it plus my most-used programs.