The easiest way to test a UPS battery is to turn the power off at the wall socket and see how long it lasts before the UPS runs out of battery and the computer turns itself off. However, what you don't want to do is have the computer power off while you are in Windows that's really bad for your PC for a number of reasons. The best approach is to start the computer into the ‘BIOS’ which is the low level hardware menu that you or your IT guy may typically use when setting up the PC and configuring hardware options normally only once or twice in the lifetime of the computer. Note: don’t change anything in the BIOS!

Once you're in the BIOS the computer will stay in that mode indefinitely until you restart or turn off. In this mode you can safely test to see how long the battery will last without worrying about damaging your Windows installation by turning off the PC with all those back-end Windows files still open.

To access the BIOS mode start up the Windows PC and press the special BIOS entry key before Windows gets a chance to start up, typically you're not going to know what that special key is as they are different for every computer motherboard manufacturer but it's easy enough to try some of the more common options. Common keys are ESC DEL F10 F12.

Complete the test as follows:

  1. Shutdown the computer
  2. Turn the computer on and be immediately ready to start tapping keys on the keyboard, press one of the keys then release then press another of the keys you're aiming for around 2 press-and-releases per second.
  3. Start trying a couple of the common keys (ESC DEL F10 F12) (one at a time as above) immediately after starting the PC. One of these keys should put you into either the BIOS mode or the boot selection mode, it's not important which, we're just aiming to pause the computer in one of those modes before Windows starts up.
  4. If Windows starts up then either you weren't quick enough with your key pressing or the keys that you have chosen not the correct keys. Wait until Windows has started up fully, log on and shut your computer down again. Then repeat the process using the other two keys.
  5. Once your computer has paused in one of the BIOS screens turn off the power to the UPS at the wall. The UPS should start beeping to warn that there is no power connected to it but the computer should stay on for a period of time as this is the purpose of the UPS.
  6. Record the time that you turn off the power. Your UPS should give you at least 15 minutes of ‘uptime’ before the battery is depleted and the UPS and computer power off. Come back in approximately 15 minutes, if the computer is still running after then your UPS battery is working as expected, you can then turn on the wall power socket shut down the PC, restart and your test is complete.
    • Note that to shutdown the PC from the BIOS mode you many need to hold to power button down for more than 5 seconds.
  7. If the UPS does not provide 15 minutes of uptime for the computer or if it turns off immediately when you turn off the power at the wall socket, then it's likely that the battery is faulty and needs to be replaced.
This information has been provided for the benefit of digitalwelcomemat IT customers.
Treat this information as informative only and do not take actions or make decisions on the basis of the information contained here. All IT decisions and actions should be made after consultation with your chosen IT professional taking into account all the of the relevant factors.


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