Ups not charging!!

Discussion in 'General Electronics Chat' started by hmxa, Jul 17, 2012.

  1. hmxa

    Thread Starter New Member

    Jul 17, 2012
    Aoa guys...hope you are all problem here is that my ups is not charging the battery at what do i do to fix the problem?
  2. sbixby

    Active Member

    May 8, 2010
    In my 15 years of experience with UPSes, it's almost always an old battery. I've come to expect roughly 3-4 years out of a SLA battery in the UPS units before it's time to replace the battery.

    I couldn't begin to tell you whether your charge circuitry is not doing the job, however, but if your UPS is more than 3-4 years on the same battery, that might be the first thing I'd do - replace it.
  3. PackratKing

    Well-Known Member

    Jul 13, 2008
    aside from a " float charger " to keep it ready for duty, unless a UPS has a long duty cycle off the battery, , why would the battery go bad........even in 4 years......... I'm here for the education as well, please humor me.. :D
  4. sbixby

    Active Member

    May 8, 2010
    I can't say I know, myself, only that I've observed. I notice that a SLA in UPS duty seems to have a limited lifespan, perhaps since it's kept floating most of the time.

    My personal/primary evidence is that after a few years, a power outage at the house will only last for a few seconds before the PC goes "blip!" and my last few (dozen, hundreds?) lines of code go to the bit bucket in the sky. So after a few stages of the grief process....

    A new battery seems to take care of this situation every time, so that's my first inclination for diagnosis. I have no actual familiarity with the charging circuitry or SLA lifespan, although I know there's plenty of info out on the 'net about it.

    I have... (in retrospect....geez...) five UPSes now, some date back to pre-2000, and all are still working with semi-regular infusions of fresh batteries. I have an '98-ish APC Back-UPS 600 sitting on my desk awaiting a new battery pack right now. This unit, however, has a pair of 6v/12ah tied together, and the cost of replacing them has me thinking it's time to retire the UPS. The lamps in the switch flickers all the time too, somewhat annoying. Maybe I'll take it apart and see what makes it tick.
    PackratKing likes this.
  5. PackratKing

    Well-Known Member

    Jul 13, 2008
    OK.......The SLA part makes sense, not being "servicable" and ergo prone to drying out over time...when maintained on a float charge .
    I have seen a few larger UPS units that are powered by "wet" automotive batteries, so did not consider the other there's my something new for the day :D
  6. DMahalko

    Senior Member

    Oct 5, 2008
    The general situation is that the UPS battery capacity keeps on declining but the UPS doesn't tell you that you are losing capacity.

    The 10-second self-test that APC and some other UPS can do, does not tell you anything about the charge capacity of the battery. It does tell you that the inverter is working, and the cut-over relays are working, but that is all.

    There is apparently no way to determine cell capacity without doing a "rundown test" with a heavy load (over 50% of UPS rating) to see just exactly how long the batteries can keep going.

    Rundown testing wears out the batteries, so it's a destructive test, and it leaves you with depleted batteries so if you have an outage immediately after the test, the loads may be dropped due to no capacity remaining.

    When was the last time you ever heard of any home-user doing a UPS battery rundown test?
  7. JMW


    Nov 21, 2011
    It all depends on how important is your need. If you are a patient and receiving brain or open heart surgery, I would guess you would want the batteries replaced as per manufacturers specs. If you are trying to prevent the "blue screen of death" maybe go a bit longer. On the ship, with the heat, use, dirty voltage, etc, I found 30 mos to be about tops before you had a problem. I have two 3300 watt units, I test them each summer with an old percolator, if it makes 10 cups, I'm good to go.