I removed the battery on mine, kept the battery chip and fed 5V into the battery terminals, from Kindle's USB connector, through a diode. Without a battery it needs something that can deliver at least 1.5A, for short bursts. An older powered usb hub seems to work fine, hub is connected to my raspberry pi, and I use ssh through usb networking, no wifi, no battery, worked fine for months now.

Awesome tips. I'll try increasing the refresh interval to 2 minutes and turning off the wifi in between refreshes to see if helps with battery life.

Side note this also finally explains to me why battery life on the Kindle is SO good in airplane mode.