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APC smart ups

Discussion in 'Electronic Repair' started by Russell, May 30, 2006.

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  1. Russell

    Russell Guest

    I have a APC Smart UPS 1500va backup power supply about 3 years old.

    It is giving a failed battery error. In fact the battery is ok.

    I have removed the cover and inspected the pcb etc and no burnt or damaged
    components found.

    Has anybody seen or know a reason that can cause this problem.

    Any help would be gratefully receiver.

    Russell
     
  2. OK How do you know the battery is OK? Woltage checks, run time test etc.

    These units put the battery under load and check for ability to deliver
    power.

    You may have batteries that are OK voltage wise but have been cooked
    overcharged untill they lack capacity to sustain a load any length of time.

    They are not nice to batteries, always keep them topped off and do a
    very high rate charge after any discharge.

    Three to five years is max life we get on APC UPS batteries is you want
    good response to power probllems.


    Hugh
     
  3. JANA

    JANA Guest

    The batteries have to be load tested to know if they are good or not. The
    UPS charging system is designed to know if the batteries are due to be
    changed.

    The expected lifespan of UPS batteries is about 3 to 5 years max. Most of
    the time, they stop working at about or after 3 years.

    --

    JANA
    _____


    I have a APC Smart UPS 1500va backup power supply about 3 years old.

    It is giving a failed battery error. In fact the battery is ok.

    I have removed the cover and inspected the pcb etc and no burnt or damaged
    components found.

    Has anybody seen or know a reason that can cause this problem.

    Any help would be gratefully receiver.

    Russell
     
  4. larya

    larya Guest

    How old is the battery?...
    How did you test the battery?...
    A simple voltmeter test doesn't work....
    My suggestion....
    Remove the battery.....
    Leave the ups off for a hour or so....this will help clear the
    capacitors in the ups...
    Test the battery under some kind of load... perhaps as little a 1/2 amp
    or so....
    If the battery's voltage drops more that a volt or two, you should
    consider a new battery...
    Larry ve3fxq
     
  5. Assumption, the mother of all screwups. I've been fooled by what
    looks like a good battery, but turns out to be defective. Just
    measuring the terminal voltage is not a sufficient test. If I'm not
    sure, I use an automobile headlamp across the battery and see how long
    it will run. The runtime varies with the battery size and type, but a
    dead or dying battery will be very obvious as the bulb will not last
    very long (usually a few seconds).

    Other sloppy ways to test a battery is to just substitute a known good
    battery (or batteries). If that works, it's a good assumption that
    the previous set are bad. This is my favorite "test" method.

    Also, a physical inspection of the battery is handy. A bluging gel
    cell battery is almost certainly a dead or dying battery. It will
    eventually burst and leak caustic goo all over the UPS.
    It's easier to just smell the board to look for dead parts. UPS's
    have difficult to access PCB's. If there is a fried component, you'll
    smell it before you'll see it.
    I've repaired a substantial number of APC UPS's. In the overwhelming
    majority of cases, it's a dead or dying battery. The dying variety
    are difficult to detect. They look good, "test" good, but don't last
    very long on backup. I have some known good battery packs on the
    shelf which I substitute. (It's also a good idea to keep gel cells
    charged when in storage, so this test is a good way to recharge my
    inventory). Same as before. If the new batteries work, by
    implication, the old batteries are bad.
     
  6. Nelson

    Nelson Guest

    [snip]
    Hmm, then maybe you can help me :) I have the opposite problem, ie
    the APC UPS (BP 1400) switches to battery within minutes of being
    plugged in (sometimes immediately) and never switches back. There's
    nothing wrong with the AC as far as I can tell. I've pulled the PC
    board but it looks like a major project to trace it out and it looks
    like there are some custom chips on there anyway. Of course you can't
    get a schematic from APC and of course they want more to fix it than a
    new one would cost.
     
  7. Hmmm... I have no idea what that can be without first looking at a
    schematic of your BackUPS 1400. I'm looking at the BackUPS 600
    schematic. There's an LM339a comparator section that determines if AC
    power has been lost or restored. A big capacitor on the inputs for
    noise reduction. Kinda sounds like the initial time delay in going
    into battery backup operation is the charge time on these caps. My
    guess(tm) is that the cap is leaking.
    Can you read Russian?
    http://www.eserviceinfo.com/
    Try "APC" in the seach box. Hmmm... only the Backup 250, 400, and
    600. I don't know how close these are to BackUPS 1400 but they might
    offer some clues. I suggest you grab all of the APC schematics and
    dig through them for clues.
     
  8. Nelson

    Nelson Guest

    Yeah, I found those a while back but they don't look much like mine
    (which is kind of old). It's been sitting in the closet... maybe I'll
    haul it out and try again. Thanks for the suggestions.
     
  9. Russell

    Russell Guest

    Thank you gentlemen for you help. I have down loaded the schematic you
    mentioned and I will study them.
    The battery is being charged when the mains is connected but there is no
    load on the battery when you remove the mains. Thank you gentlemen for you
    help. I have down loaded the schematic you
    mentioned and I will study them. The battery is being charged when the mains
    is connected but there is no load on the battery when you remove the mains.
    The battery stays at about 26 + volt and no output.

    Regards

    Russell

     
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