Why would my UPS cycle on/off at about the same time each night?

[RKP5637]

I have an APC Smart-UPS 700. At about the same time each night it goes from standby into battery mode. The lights aren't blinking in the house, nothing, but it starts going into battery mode about every 5 seconds. This goes on for about 15 minutes or so intermittently and then it stops. It's like the power company is doing something?

Supposedly this UPS also monitors the AC frequency and will go into backup mode if it detects the frequency wandering. I've checked the AC line voltage, it's stable at about 125 VAC. I've heard that sometimes cycles are lost during the day because of loads on the grid, etc., and sometimes power companies increase the frequency at night for awhile to make the same number of cycles delivered each day constant. Otherwise electric clocks, for example, would lose time. Just rambling here, but I've decided there is nothing wrong with my UPS, I guess.

[DonaldsRump]

1. Can you do a self-test?

I had an APC Smart-UPS. It started acting a bit funny (it's been a few years, so I can't quite remember what it was doing, that was "funny", but I vaguely recall something about lights and beeping). I wound up changing the battery, and the issue went away.

I couldn't find the manual online for your unit, so this is a wild guess.

[RKP5637]

3. I've done the self-test and it always tests OK. It's always about the same time, 1:00 AM. It's

in my bedroom and wakes me up. It also doesn't matter if my PC is on or off, it still does the same thing. It's really really weird.

[JDC]

4. Almost every UPS issue we've had that wasn't a blow up

Was solved w/ battery replacement. APC has a pretty good website. They also provide UPS management software that may help you diagnose the problem.

Maybe there is some sort of nightly self test that is scheduled. The software may help.

Good luck, if none of this works, just change your clocks so the UPS thinks it's noon while you are sleeping.....kidding.

[RKP5637]

8. LOL, Thanks!!! n/t

[JDC]

2. How old is the unit and is there anything that increases the load on it nightly?

[RKP5637]

6. It's about 5 years old. The batteries were replaced about a year or so ago. It always passes

self-test. The only thing I can think of it's something with the frequency of the incoming power usually around 1 AM.

[matt819]

5. Mine started doing that after a few years

Drove me nuts. I bought a replacement battery. Probkem solved.

[RKP5637]

7. I think that will be my next step. n/t

[Yonnie3]

9. I had some old APC UPSs that I guess automatically self tested daily.

It drove me crazy every night. I shut them down totally for 12 hours and the tests stated happening during the day. I couldn't find any info on turning that off.

They would also do this when the utility was going into a load management period. The utility lowers the line voltage at the start of that period. I confirmed this as I was in charge of that load management at he factory where I worked. My diesel generators were starting up at the same time. The late night beeps were not load management periods.

ETA: Mine are about 17 years old now

[RKP5637]

10. "... when the utility was going into a load management period." I think that might be what is

happening here. They have been doing a lot of work on the power distribution lines because of the growth of a city down the way. I just thought of this when I read your email.

They completed the work on the lines about a month ago, but they might be doing some load balancing of sorts in the night. When it happens, it always happens around 1AM which makes me believe it's possibly some type of utility action.

I've noticed even if I shut the UPS off for a period of time, the cycling still starts about 1AM. I know this because of all things, I have the computer setup in my bedroom and the UPS wakes me up like an alarm clock. LOL Fortunately, it does not always do it, but when it does, it's about 1AM.

[Yonnie3]

11. I don't remember exactly, but the management signal would come around ten

minutes before the hour. It rarely came at any other time. Typically this would be for the hottest or coldest hour of the day and happen more in the early parts of the month and less after the months peak had been set. One a.m. doesn't seem to fit this.

[RKP5637]

12. I'm wondering if someplace there is some heavy load placed on the lines around 1AM? This is a

residential area here, but maybe there is a heavy load on the lines around 1AM? Also, they have been doing major upgrades to the power lines. Maybe there is some night crew activity someplace around 1AM? No idea.

Last time it did some weird things an underground feeder line blew up and the crews came out and replaced the lines, but that time the UPS went randomly into backup for a few seconds at a time. I was going to replace the batteries, but there is absolutely nothing to indicate it has bad batteries. It passes self test OK and if unplugged it goes into backup and supports the system with no problem at all, and the battery indicator lights stay on/stable. I think what I'll do is wait and see if it clears, eventually.

I'll post back in awhile and let you know what's happening! Thanks for your posts, really appreciate it!

[RKP5637]

13. Getting back to you per my post#12.

Hi, it stopped, just like that. A couple of days after we last talked it just stopped. It now never goes into that peculiar repetitive back up around 1AM. Also, all the lights in the area were off for about half an hour a few days ago. It must have been some type of testing they might have been doing on the power lines at night. There have been some major upgrades going on. Phew, I'm glad that's over with. Thanks for your relies and all!

[Yonnie3]

14. I'm glad it was resolved. n/t