If you are using the ACPI backend for the Battery Charge Monitor, it is important to check that ACPI is giving you the right information. If it isn't, then you will need to look into upgrading your DSDT or something else related to ACPI.
[rupert@laptop ~]$ cat /proc/acpi/battery/BAT1/info
present:                 yes
design capacity:         41040 mWh
last full capacity:      37044 mWh
battery technology:      rechargeable
design voltage:          10800 mV
design capacity warning: 745 mWh
design capacity low:     0 mWh
capacity granularity 1:  10 mWh
capacity granularity 2:  10 mWh
model number:            G71C00056110
serial number:           0000000008
battery type:            Li-ION
OEM info:
[rupert@laptop ~]$ cat /proc/acpi/battery/BAT1/state
present:                 yes
capacity state:          ok
charging state:          discharging
present rate:            11232 mW
remaining capacity:      27140 mWh
present voltage:         11400 mV
[rupert@laptop ~]$You can quickly calculate the percentage remaining using remaining capacity divided by last full capacity, you can calculate the time remaining by taking remaining capacity divided by present rate.
