I have an HD+, I usually charge it every night, and can easily get 5 or so hours of reading time on it at the brightest setting, without any issues.
Today, I started out with a full charge, and never turned the wireless on. I read about 30 to 45 minutes on it, on the way to work. On my lunch break, 3 or so hours later, I noticed the battery meter looked about half full, so I looked at the status, and it said it was down to 51%. I turned off the screen, and went back to work. I got off 5 hours later, and was taking the bus home, and noticed the battery meter definitely looked higher than halfway, so I looked at the status again, and the battery was up to 65%. 20 or so minutes of reading later, the meter had dropped below the halfway point, so I looked at the status and it was down to 35%. I decided I'd stop reading for a while, turned off the screen and put it in my bag, but then I got bored and 20 minutes later pulled it out. Immediately after turning the screen on, it flashed a warning saying the battery was at 11%. But I didn't get any more warnings or told it was going to imminently turn off, so when I got off the bus 10 minutes later, I checked the status again, and it was up to 28%. I stopped for dinner, spent about 30 minutes in a fast food place, it flashed at me at one point telling me the battery was at 15%, before I left it said it was 18%. I read on it the entire 15 minute walk home as well, and after plugging it in here at the house it said it was 27%. It's generally in the 25 to 40% range when I get home and plug it in, so 27% was at the low end of normal.
It had this wandering battery reporting issue once, months ago, but I never had problems with it again until today. I don't want the battery to be bad, because my closest B&N (until 2 weeks in mid-July) is a 2.5 hour bus ride away, which means 5 hours just to exchange the thing.
So my question is, what's the best way to reset the battery reporting? Should I let it drain all the way, and then charge it to full again? Is it better to just keep using it like I normally do, and hope that normalizes the battery usage? Any other suggestions at all?