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?

  • glimse@lemmy.worldEnglish
    26·
    1 year ago

    Oh man I went through this a few years ago…though I doubt it’s the same problem.

    I was a custom integrator and one of my clients had a beeping UPS. Unstable incoming voltage. Ok, not the first one of these to kick the bucket so I do the RMA.

    Later that same week I’m at a different client for the same thing. Call my boss and tell him we should start looking at other manufacturers, he agrees.

    RMA arrived and I install it. Later that day the client calls…the beeping is back. I call my boss and he’s at yet another house dealing with the same thing.

    “Wait…you’re at [client]'s? That’s a few blocks away. And so are [other 2 clients]. Are we sure it’s the UPS…?”

    TURNS OUT IT WASN’T! There was something fucky with the neighborhood grid (the transformer? node? I don’t know, I’m not an electrician). We talked to ComEd, they and a few weeks later they did some repairs. No more problems.