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UPS battery replacement schedule

Discussion in 'Electronic Repair' started by Warren Post, Feb 3, 2009.

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  1. Warren Post

    Warren Post Guest

    I just replaced the battery in my UPS, and notice that the old one was
    swollen and hard to remove. Searching this NG and elsewhere on the net, I
    see this means that the battery had reached the end of its life some time
    ago and should have been replaced sooner. Okay, replacing the battery
    when it reaches the end of its life cycle instead of waiting until it
    obviously fails is fine by me.

    So how do I know when to replace a UPS battery? This particular UPS has
    no self test feature and no com port with which to communicate with the
    computer, and I don't want to toss perfectly working equipment into the
    landfill just because it lacks bells and whistles to make my life a
    little easier.
  2. Jamie

    Jamie Guest

    A good test would be to pull the AC plug!"
  3. Warren Post

    Warren Post Guest

    Well, I'm seeking a way to identify when a battery needs to be replaced
    *before* it fails the pull-the-plug test. By the time it reaches that
    point, the battery has badly overheated and swollen. Surely I need to
    have replaced the battery before that.
  4. I have used an ESR meter to check the condition of lead-acid batteries,
    but haven't kept up with the practice. Was thinking an easy test would
    be to have test points mounted outside of the UPS that one could use to
    access each battery for an in-circuit ESR reading. Charting the results
    would probably tellone when to replace the battery(eis). (bottom of page)

    Using the Bob Parker ESR (Blue - Anatek!) kit of course! Available from
    us and others...

    John :-#)#

    (Please post followups or tech inquiries to the newsgroup)
    John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
    Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
    "Old pinballers never die, they just flip out."
  5. PeterD

    PeterD Guest

    If nothing else, just use a two year schedule. A good UPS will
    constantly evaluate the batteries and advise you when they are near
    the end of their life. But that is only for the high end ones, not a
    garden variety 500 to 1000 watt version.

    A life test (such as the one suggested by the other poster, two 100
    watt lamps (for a 400-500 watt unit) will work. You can compute how
    long it should keep the lights on, and see what you get. Generally
    when batteries get to the failure point, they discharge very quickly
    (a couple of minutes max) instead of the expected 10 to 20 minutes a
    UPS should provide.
  6. Jim Yanik

    Jim Yanik Guest

    IMO,a weak battery will fail a pull-the-plug test(under load) well before
    the batteries swell or crack open.

    It just will not have a long run time.
  7. Rich Webb

    Rich Webb Guest

    Check the data sheet? I just had to replace the battery in my home setup
    UPS and noticed that the datasheet for the replacement states "For main
    and standby power supplies. Expected trickle life: 3-5 years at 25C,
    Approx 5 years at 20C." (Panasonic LC-RA1212P)

    Actual lifetime would depend on the quality of the trickle charge, how
    often and for how long it's called upon to supply power, as well as how
    hot it gets.

    Absent a test circuit in the UPS, your best bet would be something like
    a semi-annual load test, plotting the time-to-dropout versus lifetime.
  8. Warren Post

    Warren Post Guest

    Ah, that's been my problem, then. I have never tested for longer than it
    takes my system to shut down, which is only 60 seconds or so. Now that
    I'm getting a new battery tomorrow, I'll measure the run time I get, and
    again periodically.

    Is there some rough guide as to when to replace the battery, such as (for
    example) once run time has dropped to half?

    For the benefit of lurkers reading this, you don't want to do the pull-
    the-plug test while writable media are mounted. (Not while running
    Windows, for example.) A Linux live CD (free for the download) would be a
    safe choice for this.
  9. Warren Post

    Warren Post Guest

    That's a better idea than my earlier suggestion of running the computer
    with a live CD. I'll go with your idea.

    "" -- that's a great domain name!
  10. Jim Yanik

    Jim Yanik Guest

    half seems reasonable.
    you know you're on the downside of the battery's life at that point!
  11. I just replaced the battery in my UPS, and notice that the
    You, uh, weren't topping it off with a Viagra soulution, were you?

    In all seriousness... You just wait until the battery won't take a charge,
    then replace it. This means you might have to be without the SPS for a few
  12. Well, I'm seeking a way to identify when a battery needs to be
    Not necessarily. The battery might conceivably have been damaged by a
    problem with the SPS.

    If you're worried about the same thing happening to the replacement, simply
    open up the unit once a month. Most SPSs let you open them without
    disconnecting anything. (The APCs do, anyway.)
  13. For the benefit of lurkers reading this, you don't want to do the pull-
    As long as nothing is being written to the media, this isn't a problem. I
    can state as a fact that Windows 2000 will tolerate a cord yank without
    damaging the operating system. (This is not true of all OSs.)
  14. Warren Post

    Warren Post Guest

    Actually, filesystem corruption is a subject I can address with more
    authority than UPS batteries. I personally have seen and dealt with
    several instances of filesystem corruption on Windows 2000 (and using the
    more robust NTFS, not DOS) following a power failure when the box was
    sitting idle.

    A few caveats are in order:

    Your condition is important and bears emphasis: "As long as nothing is
    being written to the media". Good point. Recall, however, that all modern
    filesystems improve performance by caching data and writing to the media
    later during system idle times. This means that at any given moment a
    filesystem may have dirty data, i.e. data cached that needs to be written
    to the filesystem but hasn't been done yet.

    To deal with (among other things) power failures that cause lost dirty
    data and corruption, a journaling filesystem should normally be used.
    Windows' default NTFS is journaling, and so it is indeed more robust than
    its predecessor DOS in dealing with power failures. But perfect it ain't,
    as I have repeatedly seen.

    I haven't run any tests, but my unscientific observations lead me to
    consider NTFS to be better than DOS but less robust than any other
    journaled filesystem I am familiar with. So when I am setting up a
    Windows box, I'll use NTFS, but only because Microsoft doesn't offer
    anything better. If I'm setting up a Linux or other *nix box, I have a
    choice, and I usually choose something bulletproof like XFS or EXT3.

    Back to load testing UPS batteries. Jeff Lieberman successfully convinced
    me elsewhere in this thread that incandescent lights make a far better
    load than any computer running any OS. If for some hypothetical reason I
    had to load test using a running box, it would be with no writable media
    mounted, and as far as I know (correct me if I am wrong) that is not
    possible with Windows. I will, however, cheerfully concede your point
    that with Windows on NTFS you can *usually* get away with it.
  15. There's another point here... You should have the software configured so
    that the computer shuts down fairly quickly after power is lost (within two
    minutes or so). That will give you time to do it by hand if you're sitting
    at the computer, while not (likely) running out of battery power before the
    machine shuts itself down.
  16. 1PW

    1PW Guest

    Hello Warren:

    In a previous life, I oversaw many systems with UPS protection. Some of
    the UPS systems helped with super mission critical applications. As is
    hinted in your post, your UPS(s) are not as fully featured as many are
    today. You might wish to consider slowly moving your current UPS
    system(s) to less critical applications while replacing them with higher
    tech models. Some manufacturers had been offering a trade-up program at
    one time.

    Most manufacturers will offer a load chart to predict the rundown time
    of a new/quality battery under various load conditions. While
    maintaining some of my UPS systems, I obtained a short heavy-duty
    extension cord and I stripped off the outer insulation covering to reach
    the individual wires for ease of current measurements. I used various
    combinations of output adjustable space heaters and heavy-duty soldering
    irons to establish differing power testing loads. I found the
    predictive charts rather accurate.

    Some UPS manufacturers do seem to overcharge their batteries as has been
    reported in other threads. This in combination with various repeated
    full discharge cycles will limit the overall battery life of anything.
    Where a UPS was lightly loaded and not driven to battery exhaustion more
    than a few times, I'd see batteries last for five years. Less favorable
    conditions gave us sometimes just three years. Worst case I saw was
    about two years battery life.

    Where a situation warranted it, I've mounted muffin fans directly to UPS
    exhaust ports to improve air flow in rack mount configurations. Ugly
    but effective.

    Your reported observation would lead me to believe that your UPS is
    overcharging its battery. I believe this is not easily dealt with and
    probably not correctable without modifications.


  17. To prevent data corruption during a pull-the-AC-plug test, just
    interrupt the bootup process so that you're sitting at a pre-Windows
    screen. Or boot from a DOS floppy. All components will be consuming
    power (though read/writes) take a bit more power) and you can accurately
    gauge how much reserve time you've got. The problem with an
    incandescent bulb test is that it is not your computer. Yes, it is
    standardized, unlike the computer, but equating its results to computer
    backup time is difficult.
  18. Per 1PW:
    Here's a question that's been in the back of my mind since I
    found out that my APC unit uses a proprietary battery: How about
    a UPS that uses a plain old non/vented automobile battery?

    - Definitely non-proprietary.

    - Probably has a lot more capacity than most consumer-level UPS's

    - Quickly replaceable

    - Probably cheaper, since it's a commodity

  19. 1PW

    1PW Guest

    Hello Pete:

    We never had to try something like that. We only needed something to
    absorb sudden dips and spikes. Our UPS systems just needed to last long
    enough for our banks of big diesel driven generators to start, stabilize
    and switch in.

    However, your question is excellent. The problem lies in the design
    differences of the batteries.

    Typical thin plate automotive batteries will not withstand many deep
    discharge cycles.

    I believe the old adage that an automotive battery looses one year's
    life for each deep discharge, is still mostly true. I believe that
    sulphate damage begins with the very first deep discharge and would
    accumulate with each additional deep discharge.

    Industrial grade Sealed Lead Acid (SLA) batteries are constructed to
    withstand these cycles with extra thick plates. This is not to say that
    an automotive battery couldn't be used in a rare emergency, but to see
    continued use would call for the proper industrial deep cycle type battery.

    Someone may post a follow-up in this thread regarding the unmodified
    UPS, sensing the automotive battery's soon dwindling voltage as an
    unanticipated/early battery discharge.

    I suppose you could look into using true/real marine/RV batteries, and
    possibly modifying your UPS. However, UPS manufacturers are usually not
    very forthcoming with their product's maintenance manuals, schematics,
    piece parts, etc.

    I encourage you to Google this for a deeper understanding.

    My warm regards to you.

  20. PeterD

    PeterD Guest

    You would want a deep cycle battey... Which will not be cheap(er) but
    whatever floats your boat so to speak!

    I'd use something like an Optima (there are many similar brands). A
    regular non-deep cycle battery *will* fail very quickly as they don't
    like being fully discharged.

    Check WalMart (if you're in the US) for deep-cycle batteries.
    (Sometimes these are referred to marine batteries, but check
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