Freezing and Charging [ Edited ]

[Timenorian]

I plugged my Nook Simple Touch into my computer to put some books onto it.  The green light stayed on and stayed green.  The system page on the Nook said "not charging".  The battery was at 96%.  Is that normal for the Nook to not try to charge even though the battery is below 100%?

Then I ejected it and unplugged it and turned it off.  Then a moment later I thought of something else I wanted to change so I plugged it back in.  The screen started to change to the boot screen but then froze partway through with a large black bar down the left side of the screen.  It just froze that way.  I held down the power button and it turned on succesfully.

Then I ejected it, turned it off, and unplugged it again.  Just out of curiosity, after waiting about 20 seconds, I plugged it back in again.  It did turn on this time, however the boot screen was filled with a very dark fuzzy background across the entire screen.  When it got to the boot screen where the animated circles start cycling, the fuzziness cleared.

So my question is... huh?  Is this a deffective unit?

[gstone]

It's not uncommon for the battery to charge up to +90% and not 100%. Give it some time to calibrate the battery meter.

Turn your nook on before plugging it into your computer. It sounds like your USB port isn't providing suffient power to boot the device.

[Timenorian]

Thanks for replying.

The first time I charged my Nook -- by way of my computer -- it did charge up to 100%.  That wasn't my question.  At the time of my post, the charge had dropped to 96% through use.  However, when I plugged my Nook in again, it wasn't charging.  So, my question was, is there a certain threshold where it will only charge if it's below that threshold, and above that threshold it won't charge?  Or was this an anomoly with my unit?

My USB ports actually do provide good voltage.  All times I had plugged my Nook in before -- including the previously mentioned charging of my Nook -- the Nook had powered on normally from being plugged in.  It was just those two times I mentioned in my first post that it acted differently, where the first time it froze, and the second time it booted up completely but had a fuzzy background during the initial stage of the boot process.

[MacFlash · Accepted solution]

Many lithium ion battery programs don't charge until they drop below 95 or 90 %. This actually is advanageous in terms of battery life. I see the exact same behavior on my HP laptop as well as my Nook ST.

[Timenorian]

Awesome, thanks for letting me know.

I've also noticed that the in-book battery meter, and the home screen battery meter report two different things, but I've heard elsewhere I'm not the only one experiencing that.

[The_Nookster]

@MacFlash..

I didn't realize that about the 90 - 95% and recharging, so my question is.. "what's the best way to get maximum battery usage/life?  Should I keep it recharged all the time, or should I let the battery "run down" untill I get the warning battery low.. and THEN recharge it?"

The_Nookster 

[MacFlash]

In general lithium-ion batteries do not like deep discharges. From the battery university web site on lithium-ion batteries:

Depth of discharge	Discharge cycles	Table 2: Cycle life and depth of discharge A partial discharge reduces stress and prolongs battery life. Elevated temperature and high currents also affect cycle life.
100% DoD 50% DoD 25% DoD 10% DoD	500 1500 2500 4700

For more info go here:

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

That being said, I suspect most users will have a new fancier reader before the battery dies in their NST.

[Sun_Cat]

Interesting. That table makes it look as if there's a sweet spot at approximately 50% depth of discharge. (It could be deeper, but there are no data between 50% and 100%, so it's impossible to tell.)  I'll plan to recharge when my meter reads between 40% and 50% remaining.