High Pitched Squelching Noise From Back-UPS XS 1500 (BX1500LCD)

[Anonymous user]

For some time now (a year or so) my UPS has been making a really high-pitched squelching noise. It is an ultra high pitched, about second long, drawn out cricket sound that repeats every 3-4 seconds. Beyond that, it appears to be functioning properly and I can't tell where the noise is coming from within the UPS. I took out the battery and inspected it and it appears to be fine. Not sure if I should try to replace the battery or if it's the unit itself. Anyone have any ideas on the cause?

I also would like to point out that I moved recently and the issue occurs at the new place as well. It's an older unit, maybe 5+ years, but appears to be working fine, so don't want to replace if don't have to. But after moving the UPS is now in the living room and it's a constant annoyance.

Thanks

[Anonymous user · Accepted solution]

This noise comes from the battery charging circuit, and it's not necessarily abnormal. The newer APC UPS models use a "switching" or pulsed approach to charging the battery, and depending upon the pulse frequency, you might hear a faint hiss, buzz or squeal. (If any of these noises are really loud, that would strongly indicate a malfunction.)

How old are the batteries in the unit? If they are nearing the end of their service life, the charging circuit may be having trouble regulating itself correctly. That could produce the noise you are hearing. The average battery lifetime is between three and five years, depending upon your power quality.

[BillP · Accepted solution]

I am having exactly the same problem on my APC Smart UPS 1500.  The day before yesterday I installed new batteries and all seems to be working just fine, except for this completely maddening high pitched whine (almost sounds like a faintly audible morse code).

I am at my ropes end with this issue because I have to spend long hours at the computer and I simply can't concentrate with this high pitched beeping whine coming from the unit.  Very unhappy that buying new batteries did not resolve the issue but I see from a quick google search that I am not alone with this problem. 

Any thoughts/ideas solutions would be VERY much appreicated.

[SamirD_apc · Accepted solution]

I heard similar sounds from one of our units and it turns out that the load was every so often temporarily spiking causing an overload beep.  Try reducing the load temporarily and see if it goes away. 

[BillP · Accepted solution]

Thanks for the quick reply but clearly I'm not utilizing anything near full capacity.  I should also add new information, when I shut down all my equipment at night but not UPS (just computer, monitors and network gear), the problem seems to be gone when I start everything back up the next day.  This noise will eventually return if I leave equipment powered up overnight though, which leads me to believe this noise is coming from the charger inside the UPS?

sfv%2BApf9wbB52Fynoyr1vA%3D%3D.jpeg

[Anonymous user · Accepted solution]

My solution was to buy new CyberPower units. So far so good.

[SamirD_apc · Accepted solution]

I just acquired a model like that (750va) secondhand and it did make more noise than our older beige units of a similar design.

It could be a component starting to fail or it could be something with the batteries if they weren't a genuine apc replacement.  I've had switches and routers make odd noises like that when capacitors are on their way out.

Most of my units are out of sight/sound or the noise doesn't matter.  If the noise is an issue, you can get a newer unit and sell the existing unit.  These units do retain their resale pretty well.

[yamada]

I am having the exact same problem with my APC Smart UPS 500.
I just bought it new and it makes a high-pitched buzzing sound like a buzzing insect about once every 10-30 seconds.
Since installing the APC UPS in my office I have been suffering from headaches.
I contacted support but was told by the staff that this was a product specification and not a defect.

To my knowledge, CyberPower and Omron UPSs do not have this kind of quality problem.