If you’re noticing that your Kindle’s battery life isn’t what it’s supposed to be, or are looking for information on how to solve the "Books not yet indexed" problem, this post may help you.
I bought my Kindle Paperwhite while on vacation in Japan, where they are significantly cheaper thanks to a campaign against the entrenched Kobo readers in that market, but noticed it wasn’t living up to stated battery life claims. My previous Kindles didn’t either, but the problem was less noticeable because I used them more at the time, and thus charged them more frequently.
I recently left the Paperwhite alone during a busy stretch of two weeks and was shocked that the battery had gone nearly flat.
After poking around online, I discovered that the Calibre software I use (a popular open-source ebook manager) causes a feature of the Kindle to misbehave.
When idle, the Kindle tries to index your ebooks so you can perform word searches quickly, but if the file is corrupted or in some way fails to conform to the Kindle’s expectations, it gets stuck indefinitely trying to repeat the operation. That drains the battery, and those books never finish indexing, which must affect searching and navigation.
You can test if this issue is affecting you by performing a search for some nonsensical string such as "jejficueh" which you know won’t appear in any books. If you see a section titled "Books not yet indexed" appearing on the blank search results screen, then you have a bunch of books that never finished indexing.
For books downloaded through Amazon’s Kindle store, the solution is to delete the ebook file and download it again (at no charge).
But because we don’t have a Kindle online store here, mine is manually loaded with mobi files, PDFs, and the like. Deleting and re-copying the affected files wasn’t helping.
After reading forum posts by similarly troubled users, and some proposed solutions, I found out that Calibre does something strange to ebook files when you use the "Send To Device" button to install books on a Kindle connected to your PC/Mac. This is what you’re SUPPOSED to do, by the way. The solution is to click "Save To Disk", which outputs a clean file to some location on your computer such as your Desktop (again, Send To Device shouldn’t be doing anything different, but it does), and then manually copy the book onto the Kindle using your regular file manager e.g. the Mac Finder or Windows Explorer.
It’s probably a bug. I’ll be writing to the Calibre guys, but just wanted to put this out here in case it helps anyone.