I have had to replace the battery 3 times in just under a year.
The last battery is about a month old. I am buying the excat same battery that is in the unit so i don;t think it is the battery. My guess is that the BBU is faulty.
All I want is for the beeping to stop. I know that the unit is supposed to be for back up voice only but I have no phone in my house. This box is like the rest of my equipment. JUNK!!!! I have had Fios for just over a year and have had 3 DVR's, 2 cable boxes and two routers all die. Never had these issues with Comcast
I used to get the battery beep every once in a while. The battery did not need replacing. I just disconnected it for a few seconds and then reconnected it. See the "Battery Backup beeping and in the Red" thread currently in this forum.
A technician visited a few months ago for an unrelated issue and my battery was replaced with a newer version. There hasn't been any beeping since then.
So again, it may not be that the battery needs replacment every time you get the beeping.