APC ES550 turns off randomly

[Anonymous user]

This has been tested on three different APC backups and it keeps recurring, so I'm posting about this issue. We have used 2 different models of APC, so I don't think the size or brand is the actual problem. 

We think it's the particular circuit in the house, and we are pursuing this, but in the meantime, I'd like some input from the APC people! 

All three units have brand new batteries, so we are sure it's NOT the units per se, but something that is tripping them. My question is this: how can we tell if it's a power surge/drop issue? The outlet that is causing the most issues (MINE, naturally) seems to do *something* in the middle of the night right as the a/c shuts OFF. Not on, OFF. This has happened about a dozen times, all of which have been when the a/c shuts OFF in the wee hours. I get one long BEEEEEEEEEEEP and my Mac is down. The battery backup is not kicking in at all, it's just shutting down my Mac. (we have a new a/c unit, which is somehow linked to this problem we think)

YES it's been tested by unplugging. 
YES it is a brand new battery. 
YES everything seems to work fine. 
YES it shuts my Mac down immediately, just as if I have no battery backup at all. 

Any ideas? We are thinking it's a power surge, but we can't understand why the battery is not kicking in at all. Why would the UPS unit just kill everything? Is there some sort of failsafe for large surges? I thought a UPS was supposed to keep the computer UP during either a surge or drop so it could be shut down properly? Is that incorrect? 

I've spent about an hour reading through others' posts and I have not found any answers to my particular problem, which is probably a surge rather than a drop of power. 

Can anything be done about this or should I simply use another circuit until we can get an electrician in? All input is appreciated. 

Thanks, Angela 

[Anonymous user]

Yes, I think you should try another circuit to see if the trouble persists. However, I think what you're seeing is indicative of  what could be a much more serious problem and that you should not delay in calling an electrician.

To capture a very short duration powerline event would require some expensive and specialized equipment. The only thing I can figure is that a considerable back-EMF pulse is being induced on the line whenever the air conditioning shuts off, and that it's causing difficulty for your UPS. If this is the case, you may have to find another outlet on a different circuit and move either the UPS or the air conditioner to that circuit (if the air conditioner is a portable or window-installed type).

There are no provisions for monitoring the actual surge suppression components in your Back UPS, nor will it notice power problems having an extremely short duration. It's possible that monitoring software could shed some light on why the UPS shut down, though APC no longer distributes a version of PowerChute for the Macintosh. You could try using apcupsd, although whatever data it collects may vanish when the computer shuts down suddenly.

[Anonymous user]

Yes, we agree with your assessment. We did call an electrician and we're getting a new breaker panel next week. We knew that there were issues with the old breaker panel when we moved in, but it took a new A/C unit to upset the balance. The new A/C blower pulls power in odd ways and that is causing these random spikes/drops. The electrician moved my particular circuit to its own breaker, but then the problem moved to a different circuit (oven, oddly). So, yes, the breakers look like they were wired by a drunken lemur, so a new panel it is! 

THANK YOU for your response! 

Bottom line: this had nothing to do with the UPS, other than it freaked out and shut down rather than actually back up my computer.  

[Anonymous user · Accepted solution]

Hopefully all of the problem was with your old electrical panel and the new one will solve it. If it is not too late, I would strongly recommend that your electrician inspect all of the electrical conductors that feed the panel: all hot wires, the neutral and the ground. Any of these being loose, especially the neutral, can cause serious problems. Perhaps they have already done so.

I think the UPS could have been "seeing" an extremely high line voltage, far beyond its maximum specifications, and that its controlling logic shut down power rather than allowing your equipment to be damaged by this high line voltage.