I have also experienced the sudden battery drain on my KA1 after installing 4.4.9349. It's completely dead overnight. I noticed that the light wouldn't shut off in sleep mode, so I manually reduced it to 0%. When I picked it up in the morning the battery was dead, so I plugged it in, and then it showed the light was back to 5%, not 0%. Conclusion: another buggy update that will resolve itself with the next update. More at this thread:
https://www.mobileread.com/forums/sh...d.php?t=286953