Hopefully this is the right place to ask.

I have an APC Back-UPS XS 1400U that I use to keep my home server running 24/7.

It was purchased in 2015, batteries replaced around 2020, everything was fine until around June 2023 when it started randomly switching to battery for a few seconds for no apparent reason once or twice a day.

The UPS is connected to my home server via USB so I can get some readouts. It says “Unacceptable line voltage changes”, but it’s configured to switch when it’s outside the 160-280v range and it gets nowhere near those thresholds, the voltage fluctuates in the 224-234 range.

I connected an oscilloscope to the mains to see if there were transients when the problem occurred but I don’t see anything out of the ordinary and the problem has been getting worse, now it switches an average of 50 times a day.

The UPS still works, it can keep the server up for hours if I unplug the power, so the batteries should be good. What’s going on?

  • UnlimitedRumination [he/him]@sh.itjust.works
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    1 year ago

    How did you identify the problem and get ComEd to look into it? My UPS is switching inconsistently, sometimes a couple times a day, and I’ve seen some signs that makes me think it’s not just that UPS/outlet/breaker. I wasn’t at the point where I was going to do anything yet but since you’re talking about the same provider I have I figured I’d ask. I have a multimeter, oscilloscope and smart plugs that watch voltage/amperage/power.