Battery goes down within 15 minutes

last night when i on my UPS. that was noy operating.. not switched on.. checked and found that cabel on battery terminal is break.. n battery is full dead.. reconnect the cabel... but now problem us that my Ups off when battery(660w) is full.. but when light gone.. afyer 10 mint my ups havin beep n turn off.. on this battery i have use only 1 energy saver..

For how long have you been using this battery?

I guess problem related to battery only. you might need to change the battery soon. According to me problem indicates that battery is not discharging properly. Can you please tell me the battery capacity.