[TechniSol]

I'm assuming *CRINGE* that you didn't upgrade the firmware or perform any other jiggery-pokery prior to the problem surfacing? Absolutely no patches, customizations, Satanic, Wiccan, Druidic, Labour Party, Democratic Party, Republican Party, Freemasons, Shriners, or even ecumenical rituals, etc... ;-)

One other thought if it continues to happen might be to wipe the ereader, remove all books and test for a day or so after fully charging, or perhaps charging/discharging for a cycle or two, then add a book you know you read before having the issue and see what happens... I'd do this with Wifi/Sync off and see how it behaves. It never hurts to strip something down to the bones if there are simply too many variables to account for and you can manage to do so without great heartache. It often gets rid of a lot of possibilities unlikely to be causing the problem, but likely to be wasting a lot of effort to eliminate them. If you can build it back up step by step while testing you may just find the culprit.

Best of luck, and I hope you enjoyed the humor. We can often do with a bit when frustrated while troubleshooting something...

Personally, my money is on the somewhat trippy fuel gauge on the eReaders which occasionally requires a swift kick by running it empty and then full so it can reclaim a zero(not sure it really gets one as it's likely hardcoded to shut down at a minimum voltage, but it may shut down due to a minimum voltage defined by hardware in the battery pack signaling the battery's eminent demise with an interrupt line while noting the minimum recorded voltage measured by an A/D converter) and top off point as my guess is that it may simply note top end voltage and extrapolates or interpolates, if you prefer, to scale that range to 100% with a predefined minimum voltage that serves to cause low power screen shutdown. I have no evidence of either way that I can think of, but both represent the two likeliest design possibilities. I'm leaning toward a preset low end voltage in software since I think there are only two battery lines and it seems unlikely they'd try to encode an AC waveform over the battery voltage to communicate anything, but stranger things have happened. Trump got elected... ;-)