0

I bought a Secure 650VA UPS, but it is not working as expected.

I tested it by charging it for 6 hours. I then plugged in my desktop PC (just the PC, itself, not the monitor). I cut the power off by unplugging the UPS from the wall socket. Rather then powering the desktop for a while, it continuously sounds an alarm and then shuts down.

My PC is low-end. I don't think it consumes more than 250 watts. Here's my specs:

  • A10 6800k Richland
  • 4GiB 1333 RAM
  • Gigabyte G1-A88x Sniper board
  • 500GB Toshiba 7200rpm HDD
  • Coolermaster Seidon 120XL
  • 1 Coolermaster LED Sickle Flow 120mm
  • 1 NZXT 120mm Case Fan
  • 1 NZXT 140mm Case Fan
  • 1 Ordinary 120mm Led Fan
  • 500Watts Hec powersupply 80% efficient
2
  • 1
    "i tested it to cut the power off by removing the socket of the ups from the wall socket" -- That is an unsafe test. The UPS owner's manual probably warns you not to do that. Instead use a power strip with a switch.
    – sawdust
    Nov 24, 2014 at 9:36
  • PSU is passive PFC, should not be an issue with the UPS unit. Switchover time too long? Faulty UPS?
    – bwDraco
    Jan 6, 2016 at 5:25

1 Answer 1

1

This is an old question but it might be generally useful. There isn't enough information given for a definitive answer for this case, but here are some possibilities.

  1. The UPS could be defective. One way to test it is with a known load, like a lamp with about a 100-150W bulb (note that some UPS models won't work without at least a certain minimum load, so check the user manual and make sure you use a bulb of sufficient wattage). Plug the UPS into a power strip with a switch (this keeps everything grounded when you disconnect the power to test). Charge the battery completely per user instructions. Plug in just the lamp in one of the battery backup outlets. Then shut off the power strip and see how long it powers the lamp.

    The battery discharge isn't linear. If your computer uses 300W and you test with a 150W bulb, the computer will be powered for a little less than half as long. But this will give you a ballpark idea of how much run time to expect.

  2. The battery may not have been fully charged. Check the UPS manual for the initial charge. On some units, they suggest as much as 12 hours initial charge time before they are ready for full capacity.

  3. Watt capacity is typically much less that the rated VA. I spot-checked some popular UPS brands. APC units rated at 650VA could handle about 390-400W. A couple of Tripp Lite units could handle only 325W. It looks like your UPS is rated at 390W. If the UPS was sold to power industrial electric motors, these ratings might come close to making sense, but the VA ratings are just misleading marketing hype when they're sold for computers. You need to look at the watt rating in order to buy a properly sized unit.

  4. Relationship between watt rating and UPS performance. The watt rating actually tells you very little about performance. The primary thing it tells you is the load beyond which you will exceed the current capacity of the UPS and pop the internal breaker.

    This is another area where some UPS manufacturers get very sneaky and, again, you need to read the fine print. As I mentioned earlier, the battery discharge rate isn't linear. On some cheap brands of UPS, the "rated" power is the point at which the run time is close to useless. The advertising will read "Up to 30 minutes run time", but that's only if you are powering a nightlight. At the full rated power, the run time may be barely enough to shut down gracefully. You need to read the specs to see how long the unit will power a load equivalent to your system.

    So the watt rating always needs to be higher than what you plan to power so you don't immediately trip the thermal breaker. Depending on brand and model, however, the rating may need to be substantially higher than your load if you want a reasonable amount of run time. If your brand new, "properly rated" UPS craps out after only a minute or two, this might be your problem.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .