UPS that is UN-interrupt-able;!..

Discussion in 'Computer Information' started by tony sayer, Jan 27, 2011.

  1. tony sayer

    tony sayer Guest

    Bin there, seen that, anguished over the lack of routine maintenance in
    the leccy industry;(...
     
    tony sayer, Jan 28, 2011
    #41
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  2. tony sayer

    tony sayer Guest

    Indeed hence the questions regarding APC. Seems from a few mails etc the
    Eaton / MGE ones are better in this respect..
    Yes it is..
    About the last place I'd buy batteries from, thats a distress purchase
    location;!...
     
    tony sayer, Jan 28, 2011
    #42
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  3. What you call a significant niche is looking like it could go
    mainstream, which it will do without windows apps. It's not entirely
    unreasonable to argue it is the doomed efforts to create something
    usable based on Windows which have held things up, especially in the
    context of tablets, but you are correct that for an extended period good
    connectivity has also been a missing part of the puzzle.
     
    Espen H. Koht, Jan 28, 2011
    #43
  4. What is your need for, exactly? A true UPS will supply clean power
    during *all* mains power supply problems, but will not be cheap.

    The only reasons for using one are (a) to bridge a gap in supply or (b)
    to clean up a dirty supply. If all you want to do is bridge a gap, then
    a standby power system will be cheaper for the same capacity, as all it
    does is to take over from the mains when it fails, and is in standby
    mode, maintaining its battery charge, the rest of the time. They start
    operating within a couple of cycles of the mains going down, so most
    modern equipment won't notice the gap, but their frequency stability
    isn't always great, so something that needs a constant frequency will
    have problems.

    A true UPS runs continously, taking dirty mains in and providing clean
    mains out, with a battery backup to cover power outages. It also
    regulates the output voltage within tight limits over a wide range of
    input voltages. The continuous running requirement makes the electronics
    much more expensive, which is reflected in the price. You'll need to
    check the MTBF with the manufacturer, too.

    There is also a system for PCs to have an internal backup supply which
    will maintain the system for a specified time, though that's not what
    you've said is wanted.

    Either way, the batteries will only last a couple of years, maybe three.
     
    John Williamson, Jan 28, 2011
    #44
  5. tony sayer

    Skipweasel Guest

    I visted a farm once, on the chalk hills above High Wycome. They had a
    well in the yard - 200' deep. Eek.
     
    Skipweasel, Jan 28, 2011
    #45
  6. tony sayer

    Huge Guest

    More like "EEEEEEEEEEEEeeeeeeeeeeeeeeeeeeeeeekkkkkkkkkkkkk!!!!!" Splash.

    :eek:)
     
    Huge, Jan 28, 2011
    #46


  7. You have to do more research, but a UPS is intended for periods of seconds,
    perhaps a couple of minutes. It is for a short-term power outage that might
    happen due to switching circuits that reroute power due to lightening
    strikes on transformers. Basically, a UPS backs up the central power grid
    during momentary outages.

    The operative term here is, momentary. If you measure the outage with a
    stopwatch, then a UPS is called for. If you measure the outage with an egg
    timer, then maybe a UPS will not fit the need.
     
    Jeff Strickland, Jan 28, 2011
    #47
  8. tony sayer

    Duncan Wood Guest

    That depends solely on how many batterys you choose to use, there's plenty
    of battery UPS solutions that will run for hours, even the small Eaton
    Rack units have the option of extra battery trays, I've seen a few that
    manage over a day in places where a generator's unwanted.
     
    Duncan Wood, Jan 28, 2011
    #48
  9. tony sayer

    Skipweasel Guest

    Often just long enough to save the file you're working on. Which is
    better than nothing.
     
    Skipweasel, Jan 28, 2011
    #49
  10. Yep.

    IME, capacity drops linearly to zero at 4 years max, but it's no
    use waiting until they are zero, as you've had no effective UPS
    cover for some time. You need to take this drop in capacity into
    account when sizing and considering the battery replacement regime.
    I've kept several cars for 8 - 11 years, and never had an original
    manufacturer battery fail in that period.

    Difference in a UPS is they are charged very quickly so the UPS is
    ready for another outage as fast as possible. The higher voltage
    required to do this kills them. ISTM it would be easy to overcome
    this by falling back to standby voltage level when charged, but
    UPS's don't seem to do this, and it would reduce the manufacturers'
    revenue stream from the after-sales consumables.

    There certainly are giant commercial datacentre UPS's (the sort with
    a battery room), and things like phone exchanges, where the batteries
    can last decades, but I presume the charging circuits for these are
    designed for long battery life, because replacement of these battery
    sets costs a fortune. (I worked in one place with a 100kW UPS where
    the batteries must have been 10+ years old, and were subject to an
    annual maintence check.) We actually had the UPS fail and need
    replacing, whilst retaining all the original batteries.
     
    Andrew Gabriel, Jan 28, 2011
    #50
  11. tony sayer

    D.M.Chapman Guest


    Not always. We have plenty of UPS around the place that will supply power
    to keep core network kit running for many hours. Something in excess of 10
    hours on most.

    These are APC UPS - and are pretty good. Mind you, not the small home/small
    office ones, these have shelves of batteries.

    Also, don't expect too much from the batteries - you are talking of a small
    number of years tbh.

    We did have a minor issue with one of our main UPS (many KVa - not APC ones).
    It was installed with the wrong charging controller. First night this
    happened...

    http://www.flickr.com/photos/bcc/sets/72157604346310795/

    It hadn't powered anything at that point. Data centre smelt of sulphur for
    a while after that one - and some poor sod had the job of chiselling them
    out of the racks (the photos don't show the worst - the installer didn't
    like us taking photos of their expensive self destructing UPS ;-))

    Darren
     
    D.M.Chapman, Jan 28, 2011
    #51
  12. tony sayer

    Espen Koht Guest

    I wonder why. We cycle the batteries on our solar panel system daily all
    through the summer, and for the rest of the year they stay on
    maintenance, yet after 15 years of operation we've only on our second
    set. Do infrequent high loads really make that much of a difference?
     
    Espen Koht, Jan 29, 2011
    #52
  13. They can. I'd guess that your solar array takes a few hours to charge
    from flat, and that the load you put on the batteries would take a few
    hours to flatten the batteries completely. I'd also guess that your
    batteries are rated so that normal use only takes the charge down to
    fifty percent or thereabouts. All things designed to get the best life
    out of a set of batteries.

    Most standby applications run the batteries at a rate that will flatten
    them in less than an hour, and charge them in the same time frame. Add
    that to what is normally a not very well controlled float charge regime,
    and that will kill 'em quite quickly by comparison. Another thing that
    kills UPS batteries is that they can't be serviced, as wet cell types
    can. Solar installations I've seen have wet cell batteries that can be
    topped up with distilled water, while I've only ever seen very old
    standby installations with that type of cell, and can they last for
    ages, with care. Ask BT......
     
    John Williamson, Jan 29, 2011
    #53
  14. I have mate who lives in the out skirts of Bristol his power is
    terrible, voltage flucations and cuts several times a year. Basically
    the infrastructure hasn't kept up with development and increased
    demand.

    Out here you can probably measure the amount of undergound supply
    bewteen us and the 125kV grid in feet on the 25 mile journey to us.
    The single 33kV feed (and 11kV backup) comes over Hartside at 2,000'
    and is very exposed. Our power is pretty stable and reliable, one cut
    of hours duration every couple of years and the occasional trip of
    the auto-reclosure in late spring (tree growth).
     
    Dave Liquorice, Jan 29, 2011
    #54
  15. The electronics side of my little (700VA) APC just works, must be 10
    years old or so now. On it's third set of batteries...

    I think the problem with the batteries is that they are in the case,
    thus warm (40C ish) and the charging is not clever enough to switch
    from rapid to float. What I have found is that switching off the
    automatic battery test extends thier life noticeably, to the plus
    side of 4 years rather than 3.
     
    Dave Liquorice, Jan 29, 2011
    #55
  16. tony sayer

    Tim Watts Guest

    Dave Liquorice () wibbled on Saturday 29
    January 2011 12:11:
    I'd wondered about that battery test.

    Given you can buy a box of electronics that performs a capacity test on
    lead-acids (it does it by some clever means involving AC currents to infer
    things, rather than doing a drop-test) I wonder why such a device couldn't
    be incorporated into the unit?

    Test would involve: switch out the cells for 20 seconds, switch in the
    tester module, take reading, switch cells back into circuit. No damage to
    the cells.
     
    Tim Watts, Jan 29, 2011
    #56
  17. tony sayer

    Bob Eager Guest

    Good point.

    I have three APC UPS units here at home. The two 1400VA ones are free
    standing, and batteries last pretty well exactly three years. The 700VA
    one is in a rack (in the bottom) and batteries last two years; it does
    get a lot hotter.

    I do the battery test once a week.
     
    Bob Eager, Jan 29, 2011
    #57
  18. tony sayer

    Roland Perry Guest

    If you look at the data from UPS manufacturers (and I'm talking about
    professional UPS) then the shortest time they expect you to drain the
    batteries is about ten minutes. And the fact they give data up to an
    hour or more means they expect some of their buyers to be using them to
    bridge gaps like that.
     
    Roland Perry, Jan 29, 2011
    #58
  19. tony sayer

    Roland Perry Guest

    Mainstream PDA - yes I agree. Mainstream desktop computing - no chance.
    This appears to be some sort of anti-Windows religious rant. Like it or
    hate it, Word and Excel are the world standards for a huge amount of
    desktop computing. Agreed, they don't have to be running on Windows, but
    most people do. I've described some of the advances that I think need to
    be made for them to be realistically the choice of tablet users.
    And the need for "universal connectivity" to make applications usable is
    very much an urban myopia. The cost (and reliability) of communications
    for tablets is still way outside the parameters where I could recommend
    that people buy into what's a modern hostage to fortune. Unless it works
    for you, when it's fine.

    [I failed to connect to the wifi-enabled train I was on yesterday.
    Coupled with the impervious-to-GSM train design, one begins to give up
    on the concept. And that's without trying to roam overseas)]
     
    Roland Perry, Jan 29, 2011
    #59
  20. tony sayer

    Espen Koht Guest

    I expect there to be some convergence here, but I'm talking about
    'tablet computing' here, not desktop computing.
    That's a facile argument. I will readily admit to not being particularly
    fond of Windows, but this is a considered opinion based on my
    observation of the trajectory of 'tablet' computing going back the early
    90s (when someone tried to recruit me for a startup basing its business
    around 'Windows for Pen Computing' tablets). Let's just say that the
    importance of the current developments is not just that it is not
    Windows based, but that the front-end experience isn't based on a
    desktop OS of any flavour (including MacOS X) either. Looking back the
    desktop/start menu (or apple menu) metaphor crippled most tablet
    attempts from the outset.
    The lack of Word for the iPad doesn't appear to have become an
    insurmountable obstacle.
    Most iOS apps don't require 'universal connectivity'; that's the google
    model. A thin client model for tablet PCs is probably some way off, as
    you've identified.
     
    Espen Koht, Jan 29, 2011
    #60
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