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APC Smart UPS 600 Problem

Discussion in 'Electronic Repair' started by Isi, Oct 2, 2004.

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  1. Isi

    Isi Guest

    The APC Smart UPS 600VA (AP600) had dead batteries, and I replaced them with
    new ones. After replacing the batteries, I tested the unit with a 100W load
    (light bulb), and it switches to battery mode properly with cut AC. Once the
    load is increased to 300W (halogen bulb again) it reports low battery, even
    when the AC power is present. The unit properly switches to battery power on
    AC loss, but low battery is still on. Once the load is decreased, the low
    battery goes off instantly and it works normally. I checked the battery
    voltage and I found 26V (2X13V) with 300W load (or no load) and AC power,
    and 23.5V (2X11.75V) when operated on battery with cut AC and 300W load,
    which seems OK. Is a recalibration required after replacing the batteries?
    Thanks in advance.

    Istvan
    icsaki at hotmail dot com
     
  2. Johnboy

    Johnboy Guest

    I would check the batteries real carefully. I have found even new SLA
    batteries are bad from the get go. I would guess old stock. They must
    hold about 12.9 to 13.0 under rated amp load. If they drop to your
    measured 11.75, the battery has bad cells. Fully charged brand new
    ones are 13.0 after a 24 hour rest and will not drop volts under the
    rated load.
     
  3. Jerry G.

    Jerry G. Guest

    You must leave the batteries charging for a minimum of 12 hours when new. If
    they are still indicating weak, they may be have been in stock too long.

    You must be very sure of the source from where you buy your batteries.

    --

    Jerry G.
    ==========================


    The APC Smart UPS 600VA (AP600) had dead batteries, and I replaced them with
    new ones. After replacing the batteries, I tested the unit with a 100W load
    (light bulb), and it switches to battery mode properly with cut AC. Once the
    load is increased to 300W (halogen bulb again) it reports low battery, even
    when the AC power is present. The unit properly switches to battery power on
    AC loss, but low battery is still on. Once the load is decreased, the low
    battery goes off instantly and it works normally. I checked the battery
    voltage and I found 26V (2X13V) with 300W load (or no load) and AC power,
    and 23.5V (2X11.75V) when operated on battery with cut AC and 300W load,
    which seems OK. Is a recalibration required after replacing the batteries?
    Thanks in advance.

    Istvan
    icsaki at hotmail dot com
     
  4. Isi

    Isi Guest

    Thanks for the reply.
    What I was trying to say is that is turns on low battery when I plug in the
    300W bulb. The unit is still on AC power, the battery is at 13V(no load).
    Low battery???? If I cut now the AC, the load will be transferred to battery
    (~15A) and the battery holds at 11.75V. And yes, the batteries are fully
    charged (operating for more than a week), and I have load-tested them to
    check the capacity - they are good.

    I really appreciate any suggestions.
    Istvan
     
  5. Isi

    Isi Guest

    I measured the voltages again and I have to make a small correction:
    The batteries have 13.4V out of the circuit (no load) and 13.8V in the unit,
    when operated from AC power.
    When the 300W load is connected, the battery has still 13.8V (AC power) and
    the low battery LED comes on.
    Thanks.
     
  6. Bwibble

    Bwibble Guest

    To calibrate :-

    Using software on PC if you have it put a 33% load on the ups,
    or as close as you can get.

    Turn everything off then disconnect the serial comms lead to the pc
    and also disconnect the mains into the UPS.

    Turn on the ups with the load and run the batteries down until the
    UPS switches off.

    Re-connect the ups mains and charge the batteries then remove
    mains and discharge again, and again recharge, that should recalibrate
    the new batteries.
     
  7. Gerard Bok

    Gerard Bok Guest

    Are you sure that the meaning of the indication is 'weak battery'
    exclusively ?
    I could imagine a more general 'attention required' indicator,
    which would be triggered by both 'weak battery' and 'execessive
    load connected' situations.
    Your opservations seem to support this.

    (If it is a really smart UPS, it could sense that it probably
    would not be able to start your 300 Watt halogen load :)
     
  8. Isi

    Isi Guest

    Thanks for the reply.
    I think the procedure you described below will rather "re-form" the
    batteries after storage. The battery capacity may be updated by this (to
    reflect proper "time remaining" based on load). The low battery threshhold
    voltage will not be affected (at least I don't see how). The problem is that
    this treshhold voltage is changing based on load, and it shouldn't...
     
  9. Isi

    Isi Guest

    Does anybody have a schematic for this unit by any chance?
    The model number is "Smart-UPS 600" or "AP600".
    Thanks in advance.
     
  10. Nelson

    Nelson Guest

    I have a Smart-UPS 1600 and I suspect the controler is the same. I was
    unable to find any schematics for it... APS wants you to ship it to one
    of their repair shops. That would cost more than a new unit, which I
    guess is the plan :)

    In my case the problem is that it reverts to battery a couple of
    seconds after turning on even though it is plugged in to the AC and the
    AC is within spec. A pity... you know it has to be something simple.
    I started to make a schematic myself but there are too many
    proprietary/unknown chips to figure it out (for me at least)

    Let me know if you find one.
     
  11. When you first turn the UPS on it runs a self test during which it
    briefly runs on battery. (You can't turn it on at all if AC is not
    present). The self-test is normal. Or do you mean that it goes to
    battery after you turn it on and never reverts backs to normal AC operation?
     
  12. Nelson

    Nelson Guest

    It runs the self test, and either reverts to battery immediately or
    after a few minutes. Somehow it is thinking the AC has failed when it
    hasn't.

    Nelson
     
  13. Isi

    Isi Guest

  14. Nelson

    Nelson Guest

    Wow! Thanks! I'll admit it has been 5-6 years since I looked and gave
    up. Maybe I can fix the thing yet.

    Thanks again.
     
  15. Isi

    Isi Guest

    Just for the record: doing a "Run Time Calibration" from the PowerChute
    software fixed the problem. Simple and effective solution. Apparently the
    UPS stored some data about the old batteries, and a 300W load could have
    been hold for less than 2 minutes with the old batteries. The 2 minute
    barrier before shutdown is the low-battery threshhold, so it turned on the
    low-battery signal for the 300W load.
    Doing the run time calibration with the new batteries cleared the old
    battery data, so everything is back to normal.

    Thanks for all who helped.
     
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