XS1500 will not return to line power

[Anonymous user]

I have a 1500 with the second battery pack and running Powerchute 3.0.2.  All new batteries within the last 5 months and average drain is 250 watts.  It has been working fine until recently.  This doesn't happen every time but twice now I have had a momentary power glitch and the UPS went on battery but would not go back on line.  Thinking the power might be dirty I checked with my O'scope.  It was a clean 119V at 60 Hz.  The 1500 is set for medium sensitivity and 100 to 135V.  It will only switch back to line power if I unplug it and wait a few seconds before plugging it back in.  Then everything is fine.

Just ran the self test and it would not return to line power either.  Had to unplug and restart it.

[BillP · Accepted solution]

Hello,

This definitely does not sound right. It sounds like a hysteresis problem with voltage levels but by your measurements on the oscilloscope, it does not sound like it could really be the issue.

Beyond that, I am not sure what it could be. The first thing I know I'd try is to reset the unit but I don't think it will help. Worth a try though.

To do this, you'd turn off and remove the attached equipment and the USB cable. Turn off the UPS itself and unplug it from the wall. Then go ahead and remove the UPS battery and hold down the off button for about 20 seconds. Reconnect the battery and connect the UPS back to AC power and then you can turn it on and reconnect your USB cable and attach your load. Observe the behavior.

If no change, I'd have to say there is a problem with the UPS and if its under warranty, it should be replaced or if not, look into a replacement. apc.com/recycle lists some options there for Trading in or recycling.