Sine Wave - UPS - Battery Backup

Discussion in 'TiVo Premiere DVRs' started by michael1248, Jul 12, 2011.

  1. michael1248

    michael1248 Member

    Feb 14, 2002


    Haven't seen a thread on UPS units with "Pure Sine Wave output" yet. I was looking at this one since my previous CyberPower seems to have provided good performance. I am running 2 TiVos and a 50 inch LG Plasma. My understanding is that Plasmas do not like brownouts, hence the UPS rather than just a battery backup. Here's the one on Amazon with the Pure Sine Wave featur:

    BTW: At my previous location, the unit would click on and off every few weeks for just a few minutes at a time. Does that mean I was experiencing a brownout?
  2. lessd

    lessd Well-Known Member

    Jan 23, 2005
    I don't know if a switching power supply (used in all TiVos) cares about a pure sine wave backup power.

    The switching on/off every few weeks was to test your internal battery as i have an old backup power supply that did that also.
  3. smbaker

    smbaker Well-Known Member

    May 24, 2003
    It looks like as good a unit as any. I particularly like the two USB power ports on the front; seems there's always gadgets laying around that could use a place to plug in.

    The switching could be scheduled tests as lessd suggests, or it could have been brownouts either due to the power company or to other large loads on the same branch circuit (in particular, I have a laser printer that tends to cause nearby UPS units to go into brownout detection when its internal heater activates). Tests are a good idea; if you don't do them (either automatically or manually) than sure has heck the battery will be shot when you need it.

    I'll also respond with my obligatory 'UPSes have caused me more trouble than they have ever solved problems form actual power outages'.
  4. aaronwt

    aaronwt UHD Addict

    Jan 31, 2002
    I've never used a pure sine wave UPS and I've been using the UPSs with my HDTVs, TiVos, receivers, subwoofers, etc, for ten years with no issues.(With my PCs for fifteen years)

    For me they've caused me no issuses and has allowed me to continue watching TV, Playing a game, using a PC, receiver, etc during power outages as I normally would.

    I also have extended runtime batteries so I can get between 2 and 18 hours of use during a power outage depending on the equipment I have connected to each UPS.
  5. elwaylite

    elwaylite Member

    Apr 23, 2006
    Theodore, Al.


    I own that one and it works great. Will keep my plasma, external HDD and TWO dvr's running about 20 minutes, over 100 on just the two dvr's and EHD. Owned it since last Summer. I've had a UPS on my DVR's for years.

    Total, I have the display, two dvr's, ehd and Oppo on it.
  6. Worf

    Worf Well-Known Member

    Sep 15, 2000
    They aren't that big a deal - most things would prefer a sinewave inverter, but running things briefly off the modified squarewave you can find these days won't really hurt it.

    It may become an issue if you have a UPS that can last literally hours at a time or power motors (motors can overheat and die on modified squarewave). Or if your UPS doesn't have enough plugs and you have a surge protector instead of a plain power strip with no protection (modified squarewave inverters often trip surge protection circuits, which damages both the inverter and the surge strip).

    The use of a UPS is highly recommended, so any one is better than none and modern electronics will survive - it's only powering it for a few minutes anyhow. The only times you MUST use a sinewave is if you're powering an AC motor (e.g., power tools), or if you are plugging in surge protected power bars into the battery outlets (the normal outlets are fine).
  7. kdmorse

    kdmorse Well-Known Member TCF Club

    Jan 29, 2001
    Germantown, MD
    You can occasionally run into a device that won't run right on a square wave. Old zyxel routers for example would register a power supply fault and shut down. Sometimes a really cheap off-name Ethernet switch would power off. I had a set of speakers that would hum horribly.. But it's really, really, rare these days.

    Personally I only buy pure sine wave UPS's, partly 'just in case', partly because they may be built to a higher standard, but it's mostly just OCD.....
  8. ghuido

    ghuido New Member

    May 8, 2007
  9. L David Matheny

    L David Matheny Active Member

    Jan 29, 2011
    SE Ohio
    "Stepped approximation to a sinewave" AKA "modified sinewave" is actually a square wave with a couple of steps to make an extremely crude approximation of a true sine wave. The APC models that are supposed to put out something more similar to a sine wave are the SmartUPS models. Even for those, I've never seen a figure for Total Harmonic Distortion, which would indicate how close they really come to a pure sine wave. Having said all that, I suspect the one you bought will work just fine for powering electronic equipment.
  10. aaronwt

    aaronwt UHD Addict

    Jan 31, 2002
  11. MikeAndrews

    MikeAndrews Registered abuser

    Jan 17, 2002
    My 1500Va CyberPower UPS complained about NOT getting a real sine wave on its input.

    I powered it from a generator during our just ended 3 day power outage and it kept beeping complaining that the line frequency was 63HZ, not 60Hz.

    I have to do some more testing and reading up of the manual to see if I can turn the alarm off.

    It did seem happy with power from a 800 watt inverter on a car battery.

    Aside, my 1000va Belkin UPS which I had my TiVos on, has not come to life yet with the power restored.
  12. vman41

    vman41 Omega Consumer

    Jun 18, 2002
    I wouldn't think the line frequency says anything about the wave form other than the wavelength, it could otherwise be perfectly sinusoidal in shape.

    I don't have an oscilloscope, but my multi-meter has a frequency function. When on battery, my Cyperpower and APC SmartUPs read 60 Hz, the Back-UPS reads 180.
  13. ncbill

    ncbill Well-Known Member TCF Club

    Sep 1, 2007
    Western NC
    IIRC, switching power supplies shouldn't care about the shape of the AC waveform.

Share This Page

spam firewall