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?
I tested live to ground, live to neutral, both in and out of the UPS, and I couldn’t see anything out of the ordinary.
The input signal isn’t a clean sine wave but it’s not dirty either, I’d say it’s sine with some extra harmonics and a little bit of noise. There were no sudden peaks or meaningful variations even while the UPS was switching furiously.
I don’t have CFL bulbs, only LEDs. I can’t think of anything else that could be causing interference. I’ll try contacting the power company as suggested by @glimse@lemmy.world
Just for shits and grind, how about neutral to ground? They should be bonded together in the breaker box (and nowhere else), but if there is a fault, you might see some significant potential across them.
You are not logged in. However you can subscribe from another Fediverse account, for example Lemmy or Mastodon. To do this, paste the following into the search field of your instance: !selfhosted@lemmy.world
A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don’t control.
Rules:
Be civil: we’re here to support and learn from one another. Insults won’t be tolerated. Flame wars are frowned upon.
No spam posting.
Posts have to be centered around self-hosting. There are other communities for discussing hardware or home computing. If it’s not obvious why your post topic revolves around selfhosting, please include details to make it clear.
Don’t duplicate the full text of your blog or github here. Just post the link for folks to click.
Submission headline should match the article title (don’t cherry-pick information from the title to fit your agenda).
No trolling.
Resources:
selfh.st Newsletter and index of selfhosted software and apps
I tested live to ground, live to neutral, both in and out of the UPS, and I couldn’t see anything out of the ordinary.
The input signal isn’t a clean sine wave but it’s not dirty either, I’d say it’s sine with some extra harmonics and a little bit of noise. There were no sudden peaks or meaningful variations even while the UPS was switching furiously.
I don’t have CFL bulbs, only LEDs. I can’t think of anything else that could be causing interference. I’ll try contacting the power company as suggested by @glimse@lemmy.world
Thanks for all the replies.
Just for shits and grind, how about neutral to ground? They should be bonded together in the breaker box (and nowhere else), but if there is a fault, you might see some significant potential across them.
You’ve tried different outlets?
From neutral to ground there seems to be just some noise and a bit of DC.
Yes, I tried different outlets, doesn’t make a difference. I checked the wiring inside the plug too, the connection seems solid.