RC1 of Collin_ph battery tweak has been released.
Due to several changes, etc.. I'm starting a new thread here: http://forum.xda-developers.com/showthread.php?t=762283
UPDATE - Beta 10 released 08/16/2010
Sorry about 2 updates really quick-- this latest release was to address 2 bugs that cropped up.
Description: Battery tweak is a collection of settings that enable the hero to optimize battery lifetime. I get 35+ hours on my hero with the tweak installed with the normal 691mhz settings. When on battery power, the cpu is gradually lowered (configurable) as the battery drains, and when put on power, the cpu is put into high performance mode. Most settings are configurable.
Beta 6 includes an optional LED fix if your charging LED is hanging, and some optional performance tweaks to the cfs scheduler. For more information see the documentation linked below.
Simply download the tweak and flash.
Reboot and under adb shell run batt-cfg
Note: Make sure you are root first by running su if you are going to run batt-cfg through terminal.
You may change the settings at any time by running batt-cfg again and settings will take effect without rebooting.
New verison as of 08/16
Documentation (Updated for Beta 10):
This tweak will conflict with setCPU and OCWidget, so please disable them.
Can I say it again. Don't use set CPU, or OCWidget. You don't need them with this tweak. If you want to customize your CPU, simply run the customize utility in batt-cfg -- you can set your min/max clock speeds there. Thanks!
Customizable Battery Tweak with 2 presets
LED Fix for charging LEDs that are stuck on
Experimental CFS (completely fair scheduler) performance tweaks
Audio quality fix for froyo (disables stagefright)
Disk tweaks (mounts all mount points noatime,nodiratime)
Probably more I'm missing.
If you want to try this tweak in another rom, your rom will need a /system/etc/init.local.rc file-- that's where the service is started.
Additionally, it won't do much good unless it's on a clockable kernel.
There are other prerequisites such as sh existing in /system/bin but generally speaking if it starts up, it should work. If your rom has no /system/etc/init.local.rc, you can add the file and "import" it (I believe), within the init.rc of the boot image, but it'll require a little work.