Smart-UPS 700 continuous beep and no lights

[Anonymous user]

There was a small power blip at the premises and afterwards everything came back up except the UPS! It no shows no lights and has a continuous beep.

I've tried a different power cable, and tried plugging it in when nothing is attached but still the same.

Is the battery dead or has the UPS failed completely?

[Erasmus_apc · Accepted solution]

Is this a continuous set of beeps or one constant tone? Also, how old is the unit (serial #) and have you ever replaced the battery? If there are any accessory cards installed in the unit or communication cables, unplug them and try again. It sounds like the UPS is the problem but it would be nice to have all the information.

[Anonymous user]

It's a bog standard SU700 with no additional extras or cards. About 4yrs old (I think) serial # JS0327015270

The beep is one long continuous beep/tone and not a series of beeps.

It still happens when the only thing plugged in is the power lead.

I too think it's the UPS itself that has failed, which is kinda ironic as that's supposed to protect everything else when the power flips; but then perhaps you could say it has done that, just as a one time event, LoL

[Polychrome]

   The good new is the UPS is fine, the bad news is the batteries may need replacing. This happens when the battery voltage is in some unstated low state of charge range that is actually a surface charge with no real power available. it convinces the unit it has enough charge to do something on battery power that removes the surface charge causing the voltage to drop and hang the UPS in an alarm mode.
   Push the power-off button and let the batteries charge a bit before powering on, or remove and recharge the batteries outside the UPS. I can’t recall if I’ve ever had to remove the ac power and battery to quiet one stuck in this state, or that’s what I did because I intended to charge the batteries outside the UPS. I’ve had 7 SU700’s since 1999 and everything has happened at least twice.
   This seems to happen after a power failure when the batteries are close to end of life or failed or the battery quick connects have become loose or corroded, often both. The quick connect shell can be released and pushed up the cable to examine the contact.. Look into the connecting end to see the locking tab to be disengaged. I usually break the handle of a wooden stick swab to make a non-conductive non-marring tool but a small jewelers screwdriver or even a straightened jumbo paper clip will do the job. If corroded replace the contact. If malformed it takes only a modest effort to adjust, but replace is still preferred. 
The UPS has always returned to normal operation with contacts in good condition and good batteries charged to anything between 12.6v and 14.4v each, but I don’t know the precise voltage range where this happens.