[Nut-upsuser] Smart-UPS staying in OB after power return

[Kris Jordan]

John Morris wrote, On 9/21/2013 6:19 PM:
> Hi Kris,
>
> On 09/21/2013 05:11 PM, Kris Jordan wrote:
>> John Morris wrote, On 9/21/2013 11:28 AM:
>>> The most distressing problem is the UPS stays OB after removing and
>>> reapplying utility power.  When power is removed, the UPS goes OB and
>>> upsmon detects the power failure no problem, reporting
>>> 's0-ups0 at localhost is on battery'.  But when power is restored, there is
>>> no clicking of contactors, no switch back to OL, and no detection by
>>> upsmon that power is restored.  The UPS can be manually put back OL with
>>> 'upscmd load.on'.  I would expect the UPS go back OL automatically,
>>> though; am I wrong about this?  (APC forums folk are thus-far silent on
>>> this question.)
>> Pull the batteries and unplug the UPS and press the buttons to fully
>> discharge the UPS. Disconnect the serial/computer interface connection.
>> Re-connect the batteries, plug into utility. Do not re-connect the
>> computer interface. Now that we have rebooted the UPS, see that it works
>> like it should.
> I've done this a few times already after reading a 'braindeading'
> procedure.  With cable installed or not, removing utility power switches
> to battery; restoring power remains on battery.
>
> Is that how it should work, or not?

Definitely not.

> Since we got the UPS, it has only been under testing without any load 
> (I just plugged a 200W lamp in for fun). These issues have been 
> persistent since the first time the new batteries were installed and 
> the unit was powered up two days ago. My question remains: The on-line 
> LED should not flash incessantly, and removing and restoring mains 
> power should cause the UPS to switch to OB and then back to OL without 
> intervention, correct?

Yes.

I've not seen this behavior myself even with bad batteries and a wrong 
battery constant. Might want to check the batteries with multimeter to 
be sure. Disconnect and allow them to sit for a day, then check the 
voltage of each one. They should all be fairly balanced, and I would 
expect something just above 13V.

The UPS itself is going to be pretty aged by now if it has been in use 
most of that time.