Free battery software for linux

Battery OSD is a program that displays battery information and other types of system information on screen with the OSD library.

battery_monitor is a small battery monitoring program for Linux, that you can run in the background from your desktop session or launch from the boot scripts. battery_monitor is designed with simple goals in mind and provides acoustic and/or visual alerts when your battery level is low or when it is fully charged, so you can take apropiate actions.
Compilation and installation
To compile and install battery_monitor you need several components installed on your computer:
C compiler (probably GCC) and the standard C libraries and headers.
POSIX threads libraries and headers (pthread.h).
X11 libraries and headers.
xine libraries and headers.
make tool.
To compile the program, once you have installed everything needed, run make from the source code directory. To install it, run make install after compilation. This last step may require superuser privileges depending on the selected installation directory. The following parameters may be useful while compiling and installing:
CC: It lets you specify the C compiler name instead of gcc.
CFLAGS: You can use it to change the optimization level and/or specify additional header directories by using extra -I arguments.
LDFLAGS: In case the compiler cant find some of the required libraries, use this parameter to pass additional -L arguments in the link step.
PREFIX: The default prefix is /usr/local. If you change this parameter you should change it in both the compilation and the installation step. Its only used in the installation step for now, but this may change.
DESTDIR: Useful for package maintainers, this lets you specify a fake root directory in the installation step.
Compilation and installation parameters are appended to the make command in variable assignment form. For example: make install PREFIX=/usr DESTDIR=/tmp/fake_rootdir.
Enhancements:
- Several bugs have been corrected.
- They surfaced with recent releases of the Xorg X server, and made the program behave incorrectly when displaying signs.
- The underlying sign code has been rewritten, and the program is now lighter on resources as a collateral effect. In addition, CMake support has been added to the build system.

wmbatteries is a dockapp based on wmacpiload.

It monitors up to 2 battery capacities, remaining time, current power consumption and cpu temperature.

requires recent acpi kernel

baterry monitor is a Slovakian ACPI based baterry monitor version with autoconfiguration and support for more then one battery.

Subtle application is a another tiling window manager with a slightly different approach to place the windows, in contrast to other tiling window managers like Wmii or Ion. The placement in subtle is done by tiling windows which arrange every child-window either in a horizontal or a vertical manner. Client or even tiling windows can be moved/dragged into a tile and will be arranged according to the tile type. Every window can be swapped too and shaded inside of it’s parent tile. (view)

This behaviour is mostly inspired by Wily, an emulation of ACME – the well-known Plan9 “editor”.

Configuration and theming is done with the help of Lua. Furthermore there is an extendable “statusbar” attached to the main tile. Sublets, small Lua scripts, provide features like a customizable clock or even a small progressbar for the battery capacity of a notebook.

The initial code was based on Aewm, but is meanwhile completely re-written.
Simplicty and flexibility are the goals of this project – besides not to be bloated of course. Controlling can be done either with the mouse or the keyboard – just as the user prefers.

This is small ncurses based bar designed to match the coolness of evilWM. evilbar sports a right-aligned clock, APM status and XMMS control
evilbar has successfully been built and tested on the following systems:
- FreeBSD 4.3, 4.6, 4.7, 5.0, -CURRENT
- Debian 3.0 (kernel 2.4.18-bf2.4)
- RedHat 7.3 (kernel 2.4.18-3)
Installation:
Basic:
This will get you the vanilla evilbar with XMMS control and the clock.
./configure
make
make install
Advanced:
./configure has a few special evilbar options:
--enable-apm Enables the APM module that shows battery-status
--disable-xmms Disable XMMS control

KThinkBat is a laptop battery monitor for the KDE-Kicker. KThinkBat is inspired by the "Battery Maximizer" includes with IBM ThinkPads (now Levono).
Yes, I know, there is allready a standard battery monitor KDE-Application, but it is simply too small to realize the real battery charge at first blush.
Installation:
The simplest way to compile this package is:
1. `cd to the directory containing the packages source code and type `./configure to configure the package for your system. If youre using `csh on an old version of System V, you might need to type `sh ./configure instead to prevent `csh from trying to execute `configure itself.
Running `configure takes a while. While running, it prints some messages telling which features it is checking for.
2. Type `make to compile the package.
3. Type `make install to install the programs and any data files and documentation.
4. You can remove the program binaries and object files from the source code directory by typing `make clean.
Enhancements:
- Added Czech translation send by Martin Samek
- Refactored complete internal battery handling
- Introduced new abstract base class for Bat Info
- Added new Bat Info Sum class
- Fixed bug with wrong calculation remaining time when using two batteries
- Translation updates: Bulgarian (by Aleksandar Tsankov), German, Slovak (by Jozef Riha), Spanish (Luis Sobalvarro)
- Show current power consuption as current charge rate if charging
- More intelligent remaining time calculation in battery summary mode (if only one battery present, use the more accurate value from this battery instead of generic recalculation)
- Added COPYING.LIB (LGPL) and COPYING.DOC (GNU FDL) as some files are released under these licenses (thanks to Harald Sitter from Kubuntu team)