UPS ES 750 occasional beep

[DrDawn]

I have a UPS ES 750 (model BE750G) that beeps occasionally. I hear a 1-2s beep, then nothing for an hour or two. Then it may beep again. Power light stays green as far as I can tell. (I'm not fast enough to run to it to see if the light changes while it beeps for the 1-2 seconds.)

Connected to the unit:

   in Battery Backup: large screen smart TV, Xbox Series X, Amazon fire stick

   in Surge protection: sound bar, Amazon echo dot, small alarm clock

No computer connected to it.

It's not doing any of the troubleshooting patterns in the manual so I don't think it's the battery.

Maybe an intermittent power draw change? Appreciate any thoughts or suggestions.

[Satgate]

I am also getting the same occasional beep with a solid Green LED. The PowerChute USB port is connected to a Synology NAS.  NAS is saying 100% power with Estimated Battery life of 1476 seconds.