[Cosmos]

Just an update about battery and Koreader: With the frontlight off, page autoturn every 20 seconds, auto column reading option (will require more processing) and an academic PDF full of pictures (Koreader will fully refresh the screen on almost every page turn given that this is what it is set to do when a page has pictures). It has managed 12 hours so far with 43% battery left.

I'll update the post once it's out of juice but I suspect it'll at least do 20 hours of reading time. This more than meets my needs.

The key is to turn autostandby on in koreader. (It's off by default as it can cause significant problems on other kobo devices). I set mine to 3 seconds. Standby has no effect on the screen or responsiveness of the page turn buttons on Sage. You don't actually know it went into standby. I imagine standby basically shuts off most of the CPU cores and immediately goes up to full cores once you press a button or trigger rotation for example (this is how I suspect it behaves and it isn't based on any sources). The power consumption without enabling this option is 1.5 to 2 times as much on the Sage based on my testing.