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Uninterruptible Power Supply (UPS) Interrupting Power

Discussion in 'Miscellaneous Equipment' started by Dr_J, Apr 28, 2012.

  1. Dr_J

    Dr_J Icon

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    Apr 15, 2007
    I've had a small APC 500 VA UPS in my bedroom for almost 5 years now. The only things plugged into it are my old cathode-ray tube TV, VCR, and DirecTiVo DVR. At 4:30 a.m. Wednesday, I hear a loud, single BEEEEEP. I'm looking around and see that the VCR clock has lost power, and the DVR green light is on, meaning it has to be rebooting. Translation: the UPS lost power momentarily, even though it is plugged in and there was no power outage. That night, I install the UPS software on my computer and connect it to the UPS in order to disable audible alarms. It says that the battery is fully charged and could run for 49 minutes, which is fine because I installed a standby backup generator this winter, which kicks in after 10 seconds of no power. I reset the VCR clock.

    The next morning at 5 a.m., BEEEEEP (despite disabling audible alarms the night before). VCR clock out, DVR rebooting, with the UPS plugged in and no power outage. I get up and see that the UPS green light is on, as it should be. What gives? I come out of the shower at 7 a.m. and see the DVR is rebooting again. That's it. I unplug and disconnect everything. I can't have the UPS bothering me in the middle of the night and the DVR rebooting again and again when the UPS cuts power.

    I ordered a new UPS but keep wondering how on earth could this possibly happen? The UPS was plugged in, the green light was on, there was no power outage, and the software said the battery was fully charged with 49 minutes runtime available. Yet the thing beeped and cut power to my VCR and DVR two days in a row. Is it defective? Is this common? Has anyone ever heard of this? :confused: I can't find reference to any similar problem on a Google search.
     
  2. Davenlr

    Davenlr Geek til I die

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    Sep 16, 2006
    Sounds like the battery has failed. With it fully charged (or saying so), plug a lamp into it, and see how long it actually runs. Ill bet it doesnt run very long at all.

    If its not the battery, your charging circuit probably has a bad capacitor.
     
  3. dogbreath

    dogbreath AllStar

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    Apr 26, 2006
    Franklin,...
    UPS batteries normally last about 3 years. You can replace the battery if the charging system is still good.
     
  4. Dr_J

    Dr_J Icon

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    Apr 15, 2007
    What puzzles me is even if the battery failed, why would power be cut if the UPS was plugged in?

    I'll try the lamp test tomorrow, but I already have another small UPS on order. (I was afraid to simply get a new battery in case the UPS was defective.) What worries me is that I have a bigger UPS downstairs (that's never given me a problem yet) that I have my HR24, DVD burner, and Xbox plugged into. Though bigger, it's just as old as the other but would be harder to replace because of all the interconnections in back of the downstairs setup.
     
  5. Davenlr

    Davenlr Geek til I die

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    Sep 16, 2006
    I always test my UPS about once every 6 months just to make sure its working ok. Power down the critical stuff (DVR, computer), and see how long it runs compared to what it tells me when I start.

    Ive had good luck with APC. Use a 1500VA unit for the media closet. HTPC server is on a smaller off brand which has already failed once, and was replaced under warranty.
     
  6. Dr_J

    Dr_J Icon

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    Apr 15, 2007
    That's what I have too, APC. The ?defective one is a 500 VA.
     
  7. Davenlr

    Davenlr Geek til I die

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    Sep 16, 2006
    Its hard to say what is causing the problem. If it lost power, or had a surge that caused it to switch to battery, and the battery is bad, it would fail, causing those reboots. But if the charging circuit is bad, I dont know how you could test that. APC might have a replacement battery for it. The short beeps usually mean power fail, on backup. The long beep usually means you are on your batteries last leg before shutdown.

    On my failed unit, that is what it did. It would just give a solid tone, and everything quit. The company never told me what was wrong with it, they just replaced it.
     
  8. SayWhat?

    SayWhat? Know Nothing

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    You may have been having momentary glitches on that outlet that were covered by the UPS doing the job it should.

    Some units make it easy to replace the batteries. Others make it nearly impossible.
     
  9. Dr_J

    Dr_J Icon

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    Apr 15, 2007
    I attempted the lamp test this morning. The UPS (an APC Back-UPS ES 500, by the way) had been unplugged since Thursday morning. I unplugged all the important stuff, plugged in the lamp, plugged in the UPS, and then turned it on. The lamp came on, and the green light came on the UPS. Five seconds later, power was cut, all the UPS lights went out, and it emitted a long, continuous BEEEEEEEEEEEEEEP that wouldn't stop until I held in the power button for a few seconds. I rinsed and repeated--same thing.

    Here's the concept I can't wrap my head around. Even if the battery is completely dead, why would the UPS cut power if it's plugged in??? No red light warning that battery failure is imminent. No nothing. Just no power and one long, continuous BEEP, even with it plugged in.

    Losing a small UPS and not having a bedroom cathode-ray tube TV, VCR, and DirecTiVo for a few days doesn't even register on my worry radar. What freaks me out is the possibility that the same thing could happen to my bigger UPS (an APC Back-UPS XS 1500) downstairs, where my HR24, DVD burner, and Xbox are connected and is just as old (almost 5 years) as the one upstairs. When I lost power for 48 hours during Hurricane Irene last year, the big UPS maintained power for over 2 1/2 hours before failing. (The one upstairs didn't last an hour.) After that experience, I bought a whole-home standby generator that kicks in after there's no power for 10 seconds. I just need the UPS battery to hold on for 10 seconds before the generator kicks in, so I really don't want to buy a new battery. However, if UPS's are allowed to cut power without warning whenever the battery needs replacing, even if plugged in, that really freaks me out and very much shakes my confidence in UPS's.
     
  10. TXD16

    TXD16 Icon

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    Oct 29, 2008
    If you've never replaced the battery in the five years you've owned the UPS, the battery is dead, and a dead battery can cause a UPS to do seemingly strange things.
     
  11. Super Dave

    Super Dave New Member

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    On the better UPSs the battery is what really powers your equipment, even if you are plugged in. The line voltage varies so much that it acts as a buffer or conditioner depending on the unit, delivering a nice constant flow and absorbing all of the shocks.
    I installed a Whole House Suppressor from Home Depot for under $60 that pre-conditions the entire house, but I still use suppression on my sensitive electrical products. I do notice a difference, my lights no longer "flicker".
     
  12. John Williams

    John Williams Legend

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    The lead-acid battery in these devices need to be replaced every 3-5 years. Generally 3-4 years I see on the cheaper models and 5-6 years on the better models. But this doesn't mean you can't have a battery go bad in a year or have one last a good 7 years. (I've never seen one go much beyond 7 years).
    Generally it's the heat inside these compact devices that kill the battery. Better units isolate the battery from this heat better. Plus better units regulate the charging better to thier battery, ususally making for better life.

    When a lead-acid battery goes bye bye, it's usually from sulfate that builds up between the plates in the battery. This shorting that section out. Enough build up and you get completely bad cells. Enough completely bad cells and the whole battery becomes a current sink (short).

    So.... if you don't follow the manufacture's instructions. And test your battery once in awhile. So as to replace it when it shows signs of degrading. You end of with a battery that shorts out your UPS - damaging the whole thing. Buy a new one.


    [edit]: Don't know if this is what happened to the original poster's unit. Certainly a battery can be good and the unit itself can go bad (especially if it has taken a surge at some point). If he were to take the battery out and test it independently, this would tell him a lot. It doesn't sound like he has the knowledge to do this but if there is a Batteries Plus store near by, they might still offer that service.
     
  13. Dr_J

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    Apr 15, 2007
    I have the new UPS in place upstairs, and it's fine. I did a self-test on the bigger UPS downstairs that's almost 5 years old, and it checked out fine. The battery allegedly still fills the charge meter, and no error messages were seen.

    Given this discussion, I would certainly replace the battery if need be. However, I always thought that the UPS would tell me through red lights, beeps, and/or error messages that a battery needed replacement. The old one upstairs never gave me a warning or red light to replace the battery. It just cut power and emitted a loud BEEEEEEEEP in the middle of the night. I wouldn't have thought that cutting power without warning would be the UPS's way of saying to change the battery.

    The one upstairs was very easy to swap out. The one downstairs will not be so easy, and I'd hate to replace the battery now if it still may have a couple of years of life in it. But if it's going to be like the old one upstairs and not give me a warning when it's about to fail, then that puts me in a conundrum.
     
  14. PokerJoker

    PokerJoker Godfather

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    Las Vegas
    You're finding out just how difficult it is for a device to detect the true condition of its own battery. (You're also learning how much the typical UPS software lies about what is happening.) The problem is that this is chemistry you're dealing with here, not cut-and-dried digital electronics.

    You need a new battery, for sure. 5 years is way past their usual life span.

    Actually I wonder if you might need a bit bigger UPS. That "500VA" rating is also, shall we say, marketing-driven, and does not reflect the actual capacity in watts. You might actually only be able to put less that 300 watts of load on that thing. And the devices you listed (especially that CRT TV) might be pushing that total a bit.

    Keith
     
  15. Rich

    Rich DBSTalk Club DBSTalk Club

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    You just beat me to it. Yeah, the ratings you see on the boxes of UPS devices are very misleading. That 500 VA rating includes Power Factor in the equation that comes up with 500 VA and is very misleading. Always go with the actual wattage rating that is also on the box.

    Just checked an APC box and it rates the UPS at 550VA and 350W. Now how's Joe Sixpack supposed to know what that means? The only reason I know is I called up APC and Tripplite and got them to explain to me exactly what those ratings mean.

    Long story short: Disregard the higher "VA" rating (I know VxA=W is the proper equation for wattage in a resistive device, but disregard it, it has little to do with the actual wattage you can expect to hookup to the UPS). I would recommend using the "80%" rule and only plugging devices into the UPS that total 80% of the rated wattage of the UPS.

    Keith is also correct about that TV on the UPS. That UPS is too small for a TV, it's a miracle the battery lasted 5 years.

    Rich
     
  16. Dr_J

    Dr_J Icon

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    Apr 15, 2007
    Thanks for the advice. I only have it to protect the DVR, so I'll take the TV right off of it and put it on surge protection only. The new one upstairs is only 450 VA. The downstairs one is 1500 VA and is used for the DVR, Xbox, and DVD burner; the TV is not connected.
     
  17. John Williams

    John Williams Legend

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    Oct 5, 2011
    Just like the gentleman before said, you should get out of the habit of quoting VA ratings. They are just about meaningless for the purpose (kind of like the published contrast ratios on TVs).
    Look for the wattage rating of the UPS, ignore the VA and never quote it.

    Also stated above: Add up your total wattage that your devices use and NEVER exceed the wattage rating of the UPS. Designing your load less than 80% of total available is sound advice.
    In fact, if you had a large CRT TV on that little UPS upstairs with the DVR, that may very well be what your problem was. It held out as long as it could but you were overloading the UPS this whole time - it finally gave out and started failing periodically on you.
     
  18. Davenlr

    Davenlr Geek til I die

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    I agree. If you want any run time at all during a power failure, APC recommends a VA rating of about 2X-3X the actual wattage usage, so for ~550 watts, you would need a 1500VA UPS. A 450VA UPS would only be good for about 150-200W load.

    I think the reason they use VA is because uninformed people just assume Volts x Amps VA = Watts, but that isnt taking into effect the Power Factor which gets really hairy unless you are a math major.
     
  19. Dr_J

    Dr_J Icon

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    Apr 15, 2007
    I appreciate this discussion. I only quoted the 450 VA because that's all I could remember off the top of my head; I didn't have the box in front of me. I took the CRT TV off of the battery outlet and put it on surge protection only last night.

    Maybe I'm just being naive about how a UPS works, but logically, I would have thought that the wattage issue would only apply during a power failure. If the power is on, the electrical outlet should be supplying the power, not the battery. Thus, I never considered having the TV plugged into the battery outlet as a big deal. If I were watching TV and the power went out, I would have immediately shut off the DVR gracefully and then shut off the TV. There shouldn't have been time for wattage overload.

    Edit: I see one of the responses above: "On the better UPSs the battery is what really powers your equipment, even if you are plugged in. The line voltage varies so much that it acts as a buffer or conditioner depending on the unit, delivering a nice constant flow and absorbing all of the shocks." Of course, the one upstairs is not one of the better UPS's.
     
  20. WestDC

    WestDC Well-Known Member

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