battery in my NST drains suddenly, need advice

[Guest derei]

I have a nasty problem since a while with my Nook Simple Touch. I haven't used it for a while (~4 months) then when I started to use it, it seemed ok. I charged it and used as normal. But, after ~ a week, I the battery was discharged even if a day before seemed more than 50%. I recharged it and all seemed fine. Until today. Now I remember clearly that I opened it last night, just to check battery and seemed to be more than 75%.

Today is dead.

I let Cool Reader opened, assuming that Android will close the app if in standby for too long, or I don't know...power management stuff. Could be Cool Reader that drains battery so fast or Android issue? Maybe hardware malfunction?

 

Any similar experiences?

Thanks.