I am a user since years in ubuntu and I have not come across this problem with ubuntu till date.

My battery drains off immediately after I unplug my AC power.

The options I tried:

1) checked the battery state with : cat /proc/acpi/battery/BAT0/state

present:                 yes
capacity state:          ok
charging state:          charged
present rate:            0 mA
remaining capacity:      392 mAh
present voltage:         12476 mV

Initially it was showing charging state: charging after 5mins it started displaying as charged. ! Based on that if I remove my AC Power it shows low battery notification.

2) When I run acpi : acpi -b

Battery 0: Unknown, 9%

The battery state shows as unknown. But initially when we plug-in to AC adapter

acpi -b
Battery 0: Charging, 9%, 13:04:00 until charged

3) When the check the same with : upower -i /org/freedesktop/UPower/devices/battery_BAT0

  native-path:          /sys/devices/LNXSYSTM:00/device:00/PNP0A08:00/device:02/PNP0C09:00/PNP0C0A:00/power_supply/BAT0
  vendor:               HP
  power supply:         yes
  updated:              Thu Nov  1 16:06:40 2012 (20 seconds ago)
  has history:          yes
  has statistics:       yes
  battery
    present:             yes
    rechargeable:        yes
    state:               charging
    energy:              4.2336 Wh
    energy-empty:        0 Wh
    energy-full:         33.1128 Wh
    energy-full-design:  33.1128 Wh
    energy-rate:         5.6052 W
    voltage:             12.474 V
    time to full:        5.2 hours
    percentage:          12.7854%
    capacity:            100%
    technology:          lithium-ion

Is the power stats output, It says 5hrs to charge completely, If I charge it even more than 5hrs and unplug the AC power, It again cribs stating LOW BATTERY !!

The same thing does not happen with Windows7.

Any suggestions/ help will be greatly appreciated.