Why is my PSU buzzing or crackling while using UPS battery power?
Why is my PSU buzzing or crackling while using UPS battery power?
I just assembled a new gaming PC using a Corsair HX1000i PSU, connected to my APC Back-UPS BR1500G-IN. As long as the UPS merely transfers power from the wall (it's line-interactive), or when the PSU is directly plugged in, everything works fine. However, whenever the mains power fails and the UPS shifts to battery mode, my PSU begins producing crackling, buzzing, or vibrating sounds.
I've learned that some PSUs are not compatible with the altered or stepped sine wave output from most UPSs, and this noise is likely the PSU's internal components adjusting to that change. Corsair suggests using a Pure Sinewave or Simulated Sinewave UPS for their PSUs (so my BR1500G-IN, which APC calls "step-approximated sinewave," probably doesn't meet simulated standards). It's interesting that my previous Corsair RM850x, rated 80+ gold and also used with this UPS, never made such noises and had multiple battery cycles. Are both units expected to have ActivePFC, or is the HX1000i simply more efficient?
Despite these issues, I don't experience any stability problems with my PC, even when running Cinebench R23 on battery (though the PSU does emit a similar noise under load). In real-world use, it would only take a minute or so of continuous battery operation before shutting it down. My building uses a diesel genset, which typically activates about 40 seconds after an outage.
I'm using a 6A to 16A adapter to connect the PSU to my BR1500G-IN because the UPS only provides 6A outlets and my PSU requires a 16A plug. At ~240V in my area, the current should never exceed 6A even if I draw over 1000W. Still, could this adapter be contributing to the problem? If so, why does the noise occur only when the UPS is supplying battery power rather than continuously?
Is this a sign of damage to my PSU or the entire system? Should I consider switching to a pure sine wave UPS, or can I safely ignore this noise? Is the source of the disturbance related to the waveform itself? The system is otherwise stable, but these intermittent noises are making me anxious about my new PC.
P.S. I spoke with a Corsair support representative who advised using a pure or simulated sine wave UPS (consistent with Corsair's official guidance). He also mentioned that if the PSU can't sustain battery power for more than a few minutes, the buzzing shouldn't be a major concern. However, he couldn't clarify whether APC's step-approximated wave qualifies as "simulated" according to their own criteria.
P.P.S. I also consulted a local UPS retailer, who pointed out that the voltage drop during battery mode (the city's input is ~240V but the UPS drops to about 214V) could be the culprit. They recommended switching to an On-line Double Conversion UPS (such as APC Smart-UPS SRC1KI-IN) instead of a pure sine wave model (like APC Smart-UPS SUA1500I-IND), which remains line-interactive like my BR1500G. But I'm not sure if modern PSUs are designed to handle voltages between 120-240V, especially since the HX1000i is rated for that range. How could a slight drop to ~214V trigger such noise?
But whenever the mains power fails and the UPS switches to battery mode, my PSU begins producing crackling, buzzing, or vibrating sounds.
Could this be related to power strips, surge protectors, other adapters, etc.?
How many devices are connected to the UPS and requiring its power support when the line power is interrupted?
The main goal of a UPS is to allow end users sufficient time to shut down their supported systems smoothly, not to keep running games or applications.
Are there any additional connections that draw power directly from the UPS, such as speakers, NAS, printers, etc.? I observed a switched power bar in the video—could it be used to control the PC on and off? Where is this power switch connected according to the diagram?
Please refer to the UPS User Guide or manual for information about surge protectors and power strips, as most manufacturers advise against using them.
Feel free to adjust your line diagram if needed to fit your setup.
The PSU might be making noise because it isn’t receiving enough power to keep the system running.
It could indicate a loop: Device A → Device B → Device C → Device D → back to Device A. Any electrical loops can cause issues.
More details are required.
As discussed, I'm connecting my PSU to the UPS using a 6A to 16A adapter. It's just the setup with the adapter and the UPS. The PC and monitor are the only devices drawing power from this configuration. The noise from the PSU when it switches to battery is immediate and not gradual. My system works like this: incoming 240V service → wall outlet → UPS (BR1500G-IN) → 6A to 16A adapter → power reaches the computer and then the monitor. Nothing else is connected through the UPS. The switch I used for utility power is just a standard wall outlet. I’m not using any power bars or surge protectors. The issue seems to be related to the plug adapter itself, possibly affecting the output waveform when switching to battery mode.
These two generic links can assist in grasping the concepts of pure sine wave and square waves.
It’s not surprising that support staff don’t offer direct solutions.
Much of the information shared about specifications and performance is tailored to ideal conditions, probably in a lab setting.
I wouldn’t assume a plug adapter is the main issue, but if it’s low quality or damaged, it could contribute.
Consider replacing it with a known working adapter from another system.
The voltage drop is definitely worth noting.
Most devices tolerate some variation in voltage, while others don’t.
The 26-volt difference is around 11% and might exceed the PSU’s intended range.
It’s also important to consider the accuracy of the test equipment or other sources providing the voltage reading.
They often have a certain level of error, meaning 214V could actually be closer to 210V or 218V.
That 210V is even more problematic for the PSU.
Two factors to consider: the actual voltage and its stability.
I’m not sure about the switching behavior.
Using a power bar just to mimic power loss is one approach.
But keeping the power bar on continuously to turn devices on and off could be another issue.
Check the UPS manufacturer’s documentation for compatible devices.
It might help to unplug the UPS from the wall to simulate a power outage.
You also mentioned another UPS: that’s fine (I own two).
But be mindful of potential ground loops with electrical systems.
This doesn’t seem like a major concern based on what I’ve read so far.
Just review the setup and note connections.
From APC:
https://www.apc.com/ca/en/faqs/FAQ0...ccur in,places with varying ground potentials
If the PSU doesn’t normally make noise when external power is present, it’s probably acceptable.
If the noise starts only when the UPS is active, then the issue likely lies with the PSU.
This could be due to insufficient output voltage and/or poor quality of the sine wave.
What is that second UPS—can they be swapped for testing?
Thanks for the links!
I have tried a different adapter of the same make & model (I had bought a 2-pack) and there was no difference in the noise.
I've ordered a different brand of adapter which my friend uses on his APC Easy-UPS BVX2200 (also a stepped-sinewave model) and which is known to not present any issue with his Asus ROG THOR 1200W PSU.
I'll see if it solves the problem.
So I checked the HX1000i's spec sheet (linked below) and it's rated to work with 100-240V input. Presumably so it can work in any part of the world.
So I don't see how the relatively small drop to ~214V could give it a problem.
https://www.corsair.com/us/en/p/psu...tt...b-overview
There's no power bar at all. I'm just throwing the switch on the wall outlet to simulate power loss. But I'm not unplugging the UPS from the wall though, just so it continues to remain properly grounded.
Yeah it definitely looks like a sinewave issue.
In addition to all that's been said before, do note that I've been using this same UPS in the same location with my older PC and its Corsair RM850x PSU for over 6 months and it never made any noise even when it went on battery.
It's an APC Back-UPS BX1100C-IN. It's also a stepped sinewave, but the battery is really weak and needs replacement. I wouldn't trust it to run my PC for more than a few seconds and even then I'm risking it just immediately shutting down.
I've talked with a local UPS dealer and told them to bring over a pure sinewave UPS for a demonstration.
I'll report back with any updates.