My back ups APC 650 DOES NOT OPERATE ON BATTERY

the chirp means a power event has occurred and the unit needs reset to continue operation , power events can be a few things ( to large a current was applied as a load to it , the power stayed off till battery failed and it had to charge it back up when power comes back on )

hi
try replacing the battery, if it does not at all. have to buy a new UPS because the control board is damage

They replace the batteries

try turning on the power connection

the battery back-up will smooth out the voltage, You will definitely need a battery in or else it will beep nonstop and drive you batty! the APC should have surge protected outlets already built into it. And since you will be using it outside of a computer environment, im guessing on a worksite, there will be nothing extra you need to do besides plugging it in. I would suggest plugging it into a stable voltage for the first hour or so to allow it to charge the battery.

Sounds like a charging problem.

Check the batteries first

Yes you can change the battery. All you need to do is ensure that the replacement battery has the right physical size to fit in the cabinet and meets the required spec. Simply having a larger AH rating means that it will last longer under load when it is required and will take longer to charge after it has been used.

try plugging the pc directly into the wall...if it works the UPS is defective.  You can order new batteries for the UPS online.
Battery Planet.com

Check the relay Circuit. the relay switch must be faulty