I had a CyberPower 10-outlet unit installed to protect the computer in my home office. Very soon the smoke detector just outside my office door started to sound every few hours. Having removed the unit out into the garage the smoke detector behaves normally again.

What I actually want is something that protects against power surges and quite brief power outages since we already have a natural gas power generator that picks up in about half a minute.

I imagine that it's the lead-acid battery that causes the trouble.

Is there a unit that does what I need without that type of battery?

  • 2
    Unless something is very hot in the UPS, i.e., it is failing in some unusual way, it should not cause the smoke detector to trigger. Usually, as lead-acid batteries age, they lose the ability to hold a full charge, but do not release fumes. Just replace the UPS with another. For your use, an inexpensive unit, less then US$50, should suffice. Commented Aug 2, 2021 at 22:56
  • Some smoke detectors have a carbon monoxide detector. Could it be that it triggers because of that?
    – skippy
    Commented Aug 3, 2021 at 8:18
  • MY 'PROBLEM' HAS DISAPPEARED: And I don't really know why. I left the unit in the garage, plugged in and therefore charging for a couple of days, to give it time to outgas (or explode?) if that would make a difference. Then I brought it back into my office space. No more beeps from the smoke detector since then. I hadn't mentioned this before but it no longer seems to provoke my wife's asthma symptoms either. Thanks to everyone who offered help!
    – Bill Bell
    Commented Aug 9, 2021 at 16:51

2 Answers 2


Lead acid batteries in the typical office level UPS are Valve-Regulated Sealed Lead Acid (VRSLA) and as such do not release any fumes unless something is wrong. If the unit is overcharging, the batteries may out-gas, but they may also bulge. If the unit is in an environmentally "uncomfortable" locations, the same can happen.

If the batteries are not failing in the manner described, and the unit is emitting fumes which the detector uh, detects, the garage may not be a safe location if it is connected to the mains.

UPS units that use lithium chemistry are going to be much more expensive, and based on your use description, may be overkill.

Consider that you can test the detector by removing the UPS battery and attempting to trigger the detector. Additionally, place the battery clear of the detector and attempt to trigger using the UPS unit.

If you discover that the UPS unit is the trigger, dispose safely of the unit. If it is a damaged or leaking battery, they are relatively inexpensive to replace (and are recyclable), especially compared to a high tech lithium version.


You could buy a more expensive, Lithium ION, Lithium Polymer, or other lithium type.

  • Thanks for answering. You've reminded me to come back here to mention what has happened.
    – Bill Bell
    Commented Aug 9, 2021 at 16:47

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