My Computer Switches Off When Switching to UPS

Here’s a tip for those of you with an uninterruptible power supply (UPS) or thinking of getting one.

Today, while I was working from home, there was a short dip in the power but long enough to trip the UPS and have it switch to its internal battery to power the connected equipment until the power returned. The power was off for under a second but the odd thing was that both computers connected to the UPS switched off completely and there was a red light on the UPS.

Probably not a good sign at all but I had figured that the batteries had given up the ghost. To verify, I powered up the UPS again and ran a battery test at which point everything switched off again.

It’s critically important to remember that the battery inside a UPS has a limited lifespan as do any sort of battery. Batteries will only sustain a given number of discharge and recharge cycles before they become useless (which will happen if the electricity in your area is very unreliable). Similarly, batteries will only last for a given period of time when on standby and continually topped up (somewhere between three to five years for most batteries). Ideally, you should test your UPS batteries regularly or have the monitoring software do it for you and report the results. Unfortunately, this notification didn’t come through for some reason for some reason but will be something I double check when installing the new batteries.

Anyway, new batteries have been ordered from Power On Australia so I’ll take the opportunity to do a “how to” video for the reference of others who need to undertake the same process.


    • Dhruv on April 19, 2012 at 10:42
    • Reply

    I needed to get a UPS for my Mac and was under the impression that any off the shelf UPS will do. Well… any will do, but what I learnt was that UPSs which can output a Pure Sine Wave are preferred, in fact if they can also correct the input voltage to a Sine Wave then even better.

    I eventually ended getting myself a CyberPower and when I plugged in the USB port, the Mac immediately recognized it, didn’t need any additional software. That was really awesome.

    1. Absolutely, not all UPSs are the same! Line-interactive UPSs are probably the type of UPS most people will be wanting for this very reason as they can boost sagging voltages or buck higher than expected voltages back down to the level required. Keeping the voltage continuously at the right level can make a huge difference in the longevity of your equipment (think of it as an investment, folks!).

      Sure, the standby UPSs are cheaper but they will not regulate the voltage for you and there can be a short delay to switch over to battery power (somewhere around 20 – 30ms) which may or may not be acceptable. Line interactive UPSs close the gap down to a few milliseconds which is probably better without shelling out for more expensive solutions.

      Good feedback!

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