Default Autoshutdown not working in both CM10.1 and CM11 emmc?

I'm guessing this is a hardware error or something similar on my side but was wondering if anyone else has experienced this?

When my battery gets low I get warnings but once I reach 1% my HD+ continues to remain powered for a time and then simply turns off without shutting down. I'm assuming because the power is completely drained. Don't want to damage my battery but I often don't notice if I'm reading.

Going to try a battery calibration, anyone know what the Nook HD+ average maximum mV is?

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