Kindle’s screen (e-ink) only consumes power when it paints the screen. When it is showing something it takes 0 power. That is the reason for kindle’s 3 week battery life.
Hacking kindle to only have one screensaver works like a charm for kindle’s batter life.. lot better than disabling screensaver as it prevents screensaver code from trying to paint a different screensaver every 10 mins.
Disabling the screensaver using method i previously described in http://invokeit.wordpress.com/2011/11/21/disable-kindle-3-screensaver/ works as described.
The negative side of this (disabling the screensaver approach) is that 3G (if you have 3G kindle) and or Wifi (if you configured it) will always be on and that drains the battery like crazy.
Having done kindle screensaver hack previously i thought i’ll try this
1) Jailbreak kindle (reboot)
2) Install screensaver hack. (reboot)
3) Remove all screensavers
4) copy your favourite screensaver image
And there you have it. The screen switch off works like before but since there is only one screen saver, it doesn’t keep changing. The 3G / wifi are off when screensaver comes on and everyones happy
To learn how to install screen saver hack
Update: After over a month of setting screensaver hack, with a very light use, i am please to say that the battery has only drained about 50%.
Update 2: Another 2 weeks and no drop in battery level. This is wicked.
Update 3: total duration betweeen charger 2+ months.