How to Monitor Your Laptop's Remaining Battery Time and Usage

Another dockable application that keeps track of your laptop's battery usage. Most common feature in windows world is keeping track of laptop's battery usage. This is also supported in Fedora Linux and comes with more feature. WmACPI also supports how long your laptop is running on battery mode, including the remaining batter charges shown time and percentage.

WMACPI

One interesting feature of this software is the "timer" mode, where you can keep track of how long the laptop has been "on battery". This is opposite of the information usually provided by the BIOS, which is "time remaining", and in many cases wrong. This option can be toggled at run-time. Other features such as system messages scroll on the bottom of the window, AC plug flashes when battery is charging, and green LED inside the big button flashes red if battery level goes to critical low level.

If you wish to install this dockable laptop's battery monitoring software and as long as your laptop supports ACPI, read on.

WMACPI - Dockable ACPI/APM Informative Software

WMCPI - Fedora Installation

Installation via yum downloads around 28K of rpm package filesize.

# yum -y wmacpi

Here's a text shot for wmacpi

+-------------+
|battery graph| <- visual percentage battery remaining
|[:][=] [100%]| <- [:] - on AC (blink when charging) [=] - on battery
|[00:00]  [bX]| <- [00:00] time remaining   [bX] battery being monitored.
|status   area| <- messages scroll here
+-------------+

The displayed time is averaged over 50 samples, each taken every three seconds (by default). This greatly improves the accuracy of the numbers - on my laptop, the time remaining seems to be overstated by a
good hour or so if you only sample once compared to fifty times.

Some ACPI implementations are stupid enough to block interrupts while reading status information from the battery over a slow bus - this means that on such b0rken laptops, running an ACPI battery monitor
could affect interactivity. To provide a workaround for this, current versions of wmacpi supports setting the sample rate from the command line.

The --sample-rate option specifies the number of times the battery is sampled every minute - the default is 20, and the maximum value is 600. Since -s 600 translates to sampling every 0.1 seconds, you really don't want to do that unless you're just having fun . . .

Since WmACPI runs on linux, it can also be issued from command line to check your laptop's battery status.

More change log info is available here.