[DNSB]

Hmmm... The battery in the Sage is rated for about ~20 hours reading(*). For me, that is a few days. I've attached a clip from an email that Kobo sends me each month about my reading life. It used to be lower but now that I have more spare time, I am reading more. That email shows what I read from sourced from Kobo since they stopped counting sideloaded books back in late 2020/early 2021. If I go through calibre and use the reading times/pages recorded for finished books, it adds more hours and more pages to my reading stats.

Yes, Kobo made a definite mistake going with the Allwinner B300 quad core CPU since Allwinner's chipset has a well earned reputation for lousy power management. That was the main reason the Elipsa which shared that CPU was rapidly replaced by the Elipsa 2E which moved to a Mediatek MT8113 dual core CPU. Oddly with half the cores and a 20% higher clock speed (2.0GHz compared to the B300's 1.8GHz), it is quite a bit faster at most tasks while sucking down less power. With hindsight being it's usual 20/20, even if they kept with the B300, they likely would have added a larger battery such as the Libra Colour's 2050mAh instead of recycling the Forma's 1200mAh battery.

Take a look at the KOReader development when they had extreme fun (for certain values of fun likely approved by the Marquis de Sade) implementing very aggressive power management for the Sage.

* So 30 minutes per day gives 40 days. Reading with WiFi off, backlight off, no use of stylus, etc. Given that page flips are the main time an eInk ereader is drawing power, faster readers will be penalized as they use more page flips per hour.