@roger64: Battery reports on Kobos tend to get stuck at 96%~97% for quite a while, probably when the charging logic switches to trickle charging and/or just plain stops charging to avoid an overcharge.
Rebooting nickel or the device sometimes makes it magically jump to 100%. As does plugging/unplugging. That, or the phases of the moon and/or wind speed and direction ^^.
TL;DR: Still not convinced anything's actually going wrong here

.
(That's not to say that a clear indication of when the battery actually appears to be charging in KOReader is a bad idea, because it isn't

. Although, granted, a cable hanging from the device *is* a pretty clear indication, too ;D).