Innacurate battery charge information

Battery charge is completely wrong displayed.

I'm using Linux Mint 8 Helena (and loving it) in a HP Pavilion dv5040us.

Discharging: It starts with 100%, falls in seconds to 99.0% and after a 1:30h falls directly to 5% and then 0%.
Charging: It starts with 3%, after 20min 4%, and then after a long time jumps to 100%.

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"inxi -f" output:

CPU: Single core AMD Turion 64 Mobile ML-40 (UP) cache 1024 KB clocked at 2200.00 MHz
           CPU Flags fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr
           sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up pni lahf_lm

"devkit-power -d" output:

Device: /org/freedesktop/DeviceKit/Power/devices/battery_BAT1
  native-path: /sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:0c/PNP0C0A:00/power_supply/BAT1
  vendor: Hewlett-Packard
  model: Primary
  power supply: yes
  updated: Sun Jan 31 12:56:27 2010 (3 seconds ago)
  has history: yes
  has statistics: yes
  battery
    present: yes
    rechargeable: yes
    state: charging
    energy: 2.8512 Wh
    energy-empty: 0 Wh
    energy-full: 71.28 Wh
    energy-full-design: 71.28 Wh
    energy-rate: 0 W
    voltage: 10.8 V
    percentage: 4%
    capacity: 100%
    technology: lithium-ion

Device: /org/freedesktop/DeviceKit/Power/devices/line_power_ACAD
  native-path: /sys/devices/LNXSYSTM:00/device:00/PNP0A03:00/device:0c/ACPI0003:00/power_supply/ACAD
  power supply: yes
  updated: Sun Jan 31 12:20:51 2010 (2139 seconds ago)
  has history: no
  has statistics: no
  line-power
    online: yes

Daemon:
  daemon-version: 011
  can-suspend: yes
  can-hibernate yes
  on-battery: no
  on-low-battery: no
  lid-is-closed: no
  lid-is-present: yes