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For the last two days, my Uninterrupted Power Supply (UPS) has failed to function properly. I charged it for 24hrs and again checked that when the power failed my PC was automatically shut down. But when I have power, the system is able draw power through the UPS, even if it fails to supply power when the mains supply does not.Will it cause any harm to my pc?

my questions are-

  1. Is the UPS functioning properly or not?
  2. If not, then will it harm my pc?
  3. If it is functioning, will it regulate direct power to pc without any cause?
  4. Is my UPS battery not working?
  5. What should I do to make my UPS batteries last for at least a year?

I am using FRONTECH UPS 600va (Warranty for both ups and battery is expired) I changed the battery 8 months ago.

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2 Answers 2

Sounds like the circuits that should be handling smooth changeover to battery power are not functioning correctly, which isn't all that surprising as these tend to be the first bits to go on older battery systems.

Normal power flow will work fine, but if this is the problem, then the UPS is no better than a surge protector for your machines. It may just be time to get a replacement.

For a 600va UPS, replacements are very affordable these days. here's a nice one from Fellowes for a little over $100 USD.


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If you have a correctly functioning UPS you should be able to do the following ...

  • Turn on your PC
  • Unplug the UPS from wall-power
    • The UPS should give an audible alarm (and in most cases a visible indication).
    • Your PC should continue to operate normally for several minutes, perhaps tens of minutes.
    • If an extra cable (e.g. USB) is connected and s/w installed, when it's battery charge is getting low, the UPS will eventually signal the PC to perform an orderly shutdown
  • Reconnect the power
    • the UPS alarm should cease
    • the PC should continue to operate (unless the UPS shut it down).
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