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..