BR1500GI - High-pitched tone

[Anonymous user]

Having just recently purchased and set up a Back-UPS PRO - BR1500GI - Uninterruptible Power Supply 1500VA, I noticed that there is a faint, but noticeable and distracting high-pitched cyclical sound that lasts about 5 seconds, and then repeats. It sounds like this may be associated with continual charging of the battery, although the battery is fully charged. The serial number begins with '4A' if that is relevant. It is noticeable when there are no background noises and the room is otherwise silent.

Is a sound like this normal? 

[Anonymous user]

Sounds like a less than optimal capacitor to me, could be an early indicator of a future failure or just an unlucky noisy batch of components.  If it bothers you (I'm sure it would bother me) then consider asking APC for a replacement.  I have a Back-UPS ES 700 and it doesn't make any noise at all, except when it does a self-test when it goes a bit crazy with a loud whiney noise which reduces in frequency to clicks before becoming silent again, this could just be due to it's age as it's quite old now.

[Anonymous user]

Thank you for your suggestion.

So I engaged the APC tech support on chat today, and they asked me to take the AC + battery out, and power the UPS on for 5 seconds whilst completely unpowered to perform a reset. They apparently call this a Brain Dead procedure(!).

Interestingly, after that, whilst the UPS made the same noise as soon as it was plugged back in to AC, but switched off (presumably it still charges the battery in this state?), when I switched the UPS on again using the power button, the cyclic 5s pulsed noise went away.

Whereas before, the noise was on whilst the UPS was in the switched on state with a load.

Any idea what this change in behaviour means, if anything? Could it be associated with the device + battery being brand new and needing to settle down? I wonder why the reset procedure changed the sounds?

Now upon load I hear a sort of high-frequency hissing/static noise. I was able to make a recording of this (whereas the earlier noise did not seem to get picked up by my phone). 

https://photos.app.goo.gl/xShtFT2r9EN1hbrM9

Can you hear that with volume turned up? Is this normal? I have a feeling it might be.

Certainly this is far less distracting to me than the cyclic 5s pulsed tone I was hearing.  

[Anonymous user]

My other (newer) UPS made that kind of hissing noise when switched on from being completely off and disconnected, it stopped after a while.  Possibly it could be the same components that were making the previous noise, only this time they caught a different amplitude / frequency or whatever.  Some transformers tend to hum, just like some monitors have a dead pixel or two, while still being within manufacturing tolerances.

[Anonymous user]

Good to know, thanks. When you say after having been switched on for a while, how long do you mean? Hours or days?

[Anonymous user]

Probably about 30 minutes, battery was at 74% so it must have been charging (now reads 100% and there is no noise).

[Anonymous user]

Cyclical tones are back. In general the unit just seems rather noisy.

I managed to create two videos that captures the 5s cyclic pulsed tone (but you may need to turn up volume to full).

Here is what it sounded like this morning:

https://photos.app.goo.gl/aY5JkL8CirxmzV7u5

Here is how it sounded when I switched it off and then back on. Notice how the cylical tone starts but then dies down, then it is just a sort of high frequency hissing.

https://photos.app.goo.gl/6AeShPXMr8eXT65B6

Here is the sound it makes when AC is switched off and it goes on to battery:

https://photos.app.goo.gl/NTyFhfcLjqffDVdx9

[Anonymous user · Accepted solution]

I think it's normal for them to make an audible noise when on battery, mine gives a thump and a low electrical hum.  As for the other noises, sounds to me like it's just an unfortunate characteristic of the components in your device.  I don't have one exactly like that so can't compare, but I'd say again if it disturbs you then see if you can do a warranty swap or something.  You'd probably have to discuss it with APC after sales support or whatever, I don't know if they actively monitor these forums.