Hi-

For a couple of weeks we kept hearing a half second “beep” somewhere in the house every so often.  It was about to drive me nuts trying to zero in on it since we have so many electronic devices in the home, I’ve lost hearing in my left ear making audio depth perception difficult, and the sound was so brief.  Finally defining that it was exactly every 15 minutes, we stationed ourselves yesterday at various points when it was expected to sound, and I discovered it was coming from the Frontier/Ziply fiber optic installation behind a couch in a room we rarely frequent.

I noted red lamps on it that implied the 12v battery had failed.  I removed it and rushed it to our local ACE Hardware just before they closed hoping to find a proper replacement, but they didn’t have one.  At home I checked the battery with my Fluke voltmeter and found it had 13.4 volts and wouldn’t take a charge because it was fully charged already.  I reinstalled that battery and reset the device.  The annoying beeping is gone and the green status lamp on the ONT is the only one on.

Can you advise as to what might cause the battery sensor(s) to indicate the battery had failed when it hadn’t?  It’s been many weeks since we had a power outage that might have tweaked the electronics, and we have a whole house surge protector anyway.  The fiber optic infrastructure (Arris) was installed in 2015 by Frontier, but was transferred to Ziply in 2020.  I don’t even know what “ONT” stands for, so forgive my ignorance of exactly how the system works.

Account number (edit: private information removed)

Arris ONT model # ONT1000-PS1-2G

S/N:  (edit: private information removed)

(edit: private information removed)