My battery backup UPS is "pulsing" with a gentle click every 4 seconds

It’s driving me nuts. I can feel it course through my mouse, keyboard, keyboard tray, even though I no longer have my PC box plugged into it. Anyone know what might be going on and if it’s fixable?

<<forgot to mentioned it’s an APC XS-1000>> and the “click” is more like this: “thuung”… “thuung”… “thuung”…

Old? Battery could be dying? Have you tested it by unplugging it from the power source? Do you have anything else drawing power from it? Really sounds like the many APCs I’ve had die on me in the office.

When I disconnected all devices from it, it still does that. I did turn it off to “let it rest” for 5 hours (fully off so battery wasn’t being used), and then plugged it back in and had the same result. I’ve had a host of other problems with my motherboard (USB ports disappeared) at the same time which complicated things a lot as I thought the noise and pulsing was actually coming from my PC. I guess I’m glad to hear you’ve had a similar issue as I won’t waste my time trying to salvage it. This unit was supposed to tell me when the battery was dying and apparently failed in that regard. This unit is ~8 years old I think. Is that a good lifespan?

After 8 years the battery is almost certainly insufficient to handle even brownouts. If your unit has a USB port, plug it into your computer and install the APC software to check it out. If not, just buy a replacement battery from amazon.

The software kept crashing and giving me errors when I tried to do that. I’m going with Cyberpower for a replacement. I feel like even if the battery is dead/dying it shouldn’t be freaking out and it’s made me very suspicious of the motherboard issue which just happened to occur at the same time necessitating a replacement.

I was going to suggest drilling small holes, but it sounds like you’ve got a good plan of action. In my experience, power fluctuations can also cause that mystery USB disappearance. When you have a chance and if you have the equipment, you might want to test the PSU as well (better safe than sorry - it’s likely okay).

You likely need to buy a new battery, commonly more expensive than getting a new UPS. 3-5 years is their expected lifespan.

If you buy a pretty decent UPS the replacement battery will definitely be cheaper.

ex: My UPS:, replacement batteries:

I hope I didn’t screw up. I ordered this one because it has active PFC capability and I had $50 rebate from Amazon:

My Power supply is Corsair HX1050 which I interpreted to use active PFC:

I just buy generic batteries, much cheaper than the name brands. You need to replace them every couple of years, no biggie.

I’m lucky to have a UPC last more than 2 years in this office. Of about the 20 I have that started as APC, I’ve replaced about 75% with Cyberpower ones which have never shown any issue (knock on wood) yet.

Looks like a nice one to me.

Wow that is horrendous reliability? APC sure has fallen.

Thanks everyone for your help. I think I’m finally on my way to having a fully functional computer again… One that is properly protected as well.

Could be that they are just under heavy stress in our office. Lord knows what the wiring is like in this older building.

Finally got my new UPS. Does it take up much processing power if I have to connected via USB to my computer? I normally don’t do that, but after the last incident am thinking maybe I should have it hooked up. But I hate to slow my computer down even a little bit.

Thanks for any insight!

It’s telemetry monitoring…pretty trivial. And honestly knowing if your UPS actually gets /used/ is pretty useful information.