How to solve a problem where a Kobo ereader will hang or freeze or completely drain to 0% battery life overnight
I’m posting this in the hopes of helping anyone with the same issue.
I own an older Kobo Libra H2O model and never had any problems like this, but it happened often with my new Kobo Clara Color. I would pick it up in the morning and find the battery flat. Or I’d be using it and it would lock up and require a hard reboot. It would also lose my reading position in a book when this happened.
The reason (at least for me; your mileage may vary) can be traced back to ePub files that contain errors such as improper markup or missing font specifications. This can happen if you’re loading your Kobo with ePub files other than those sold through the Kobo e-store, such as privately authored files or converted documents.
You can address these errors in the free open source book management app, Calibre. Select a book in the main list, then press “T” or choose the menu option to “Edit Book”. Then look in the toolbar for an icon that looks like a bug, which might be labeled “Run Check”. This will scan the ePub file for errors, and offer to fix them automatically. Most of the time, this will solve all problems. Occasionally, a file may have problems that can’t be fixed, in which case you may have to delete or edit some HTML elements yourself, if you know how. When you’re done, press the equivalent of ‘Cmd-S’ to save the changes, and close the window.
Finally, you’ll want to use a special Kobo-optimized form of the ePub format called KePub (or Kobo ePub) when transferring the files to your Kobo. This format is apparently fully compatible with all ePub readers, but offers enhanced performance when used with Kobos, so you may notice page turns and searches are faster.
In Calibre’s settings, go to the Plugins page and find the option to install external plugins. Search for KoboTouchExtended and install that, then configure it to automatically convert books before sending them to your device. You can refer to this Reddit thread and the links within it if you run into any trouble.
If you don’t use Calibre, there are standalone tools for converting ePub files to KePub such as this web-based one which does everything in your browser — no uploading to servers involved.
Ever since doing this a couple of weeks ago and transferring all my books over again, I haven’t run into this issue despite using it quite a bit.
Summary
Problem Cause: ePub files with errors, such as improper markup or missing font specifications, can cause freezing, battery drain, and reading position loss on Kobo Clara Color.
Solution: Use Calibre to check and fix ePub file errors, then transfer the files to Kobo using KePub format for enhanced performance.
Plugin Installation: Install the KoboTouchExtended plugin in Calibre and configure it to automatically convert books to KEPUB format before sending them to your Kobo device.