# Does the Kindle use ANY battery power while in sleep mode (wireless off)?



## newb (Jul 12, 2010)

Someone in another thread made a post that piqued my interest. This person stated that the Kindle "uses very little battery life while asleep," and that it used even less if the wireless is off.

That got me wondering about my recent problem with my Kindle's battery, where it dropped from half strength to empty in five minutes. I hadn't really touched my Kindle for several days before this happened. I was under the assumption that the Kindle used _zero_ battery power while in sleep mode (with wireless off, of course), but if it does use a tiny amount then that would explain what happened to my Kindle.

So, what's the consensus here? Don't use your Kindle for a week, and you can expect your battery to be drained? Or was my case just an isolated incident?


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## Mike D. aka jmiked (Oct 28, 2008)

The Kindle uses minimal power when in sleep mode. It does have to keep the clock running, monitor the power/sleep switch for status, indexing books, and probably a few other things. I don't believe that you can actually turn the Kindle completely off.

The battery should last for weeks in sleep mode however (with wireless turned off), unless it's indexing a lot of books.

Mike


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## BTackitt (Dec 15, 2008)

Oh sure you can turn it completely off. and even completely off, it will still use a small amount of battery life for the clock. and even when batteries aren't hooked up to anything, they do lose power over time.. albeit a LONG time, but..


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## NogDog (May 1, 2009)

^ What they said.

If you know ahead of time you will not be using your Kindle for a couple of weeks, it might be worthwhile to turn it off. If, on the other hand, a couple of days of sleeping drains the battery, it may be an indexing problem, as it seems to get into a continual processing loop if it encounters problems indexing a book. You can test for this by doing a search on a nonsense word/phrase from your home screen, telling it to search for it in all of your content. If it lists any book(s) in the results as not being searchable, you may want to delete that book and re-download it to see if you get a good version that does not cause indexing problems. (Note that when you first download it, it will still need some time before it is indexed and therefore searchable, but it should not take hours to do so.)


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## Mike D. aka jmiked (Oct 28, 2008)

If it's still using power, then it's not completely off. My definition of "off" is using no power.   

Mike


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## NogDog (May 1, 2009)

PS: There's no law that says you cannot leave your Kindle connected to the charger when you're going to leave it in sleep mode for an extended period of time (other than it probably is going to add a few cents to your electric bill you could avoid by only charging it until the battery is full).


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## pidgeon92 (Oct 27, 2008)

Even in an off position, the battery will degrade _slowly_.


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## Sandpiper (Oct 28, 2008)

pidgeon92 said:


> Even in an off position, the battery will degrade _slowly_.


Any battery does.

I got my K1 on Halloween '08. I've never turned it off.

K3 will be here TOMORROW.


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## amafan (Aug 11, 2010)

All devices use a small amount of power in sleep mode.  Others in this thread have stated articulately why this is so.  The battery will also slowly discharge over time due to internal loss even if they aren't connected to anything, although the Lithium plasma batteries used in modern devices typically have fully charged shelf life measured in years.  Why is this of such concern?  If your battery is discharging quickly, then its probably EOL and needs replacement.  lithium batteries typically have a lifetime measured in full charging cycles.  300-500 full cycles is the typically lifetime before it reaches half of its original charge retention capability.


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## newb (Jul 12, 2010)

Thanks for the info, all.



amafan said:


> Why is this of such concern? If your battery is discharging quickly, then its probably EOL and needs replacement.


I'm concerned because I'm not sure what to think. My Kindle has only done this once. There were no recent books that would have caused indexing problems. I'd just stopped using my Kindle for five or six days when the battery was at half power, and when I woke it up again the indicator still displayed half power. Still, it died minutes later.

After recharging it and using it for a couple of days, the battery seems fine. Not even a dent in the indicator. I'd be less concerned if the battery didn't hold a charge - at least then I'd know what to think. It would be a simple matter of calling customer service and getting a replacement. But it's working fine, and after what happened, that's weird. It shouldn't be fine, because if it was fine, the battery wouldn't have died like that. Now I'm going to always be worried about this happening again.

I at least have the comfort of knowing that my Kindle is still under warranty until July of 2011.


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## BTackitt (Dec 15, 2008)

If that's the case, I would just chalk it up to the indicator was probably just not quite in sync yet, and once it sync'd the Kindle battery was almost dead anyway. Now that you have charged and used it again, the indicator is once again insync.


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## newb (Jul 12, 2010)

BTackitt said:


> If that's the case, I would just chalk it up to the indicator was probably just not quite in sync yet, and once it sync'd the Kindle battery was almost dead anyway. Now that you have charged and used it again, the indicator is once again insync.


Thank you, that makes me feel a little better about it.


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## NiLuJe (Jun 23, 2010)

Also, AFAICT, the indexing cache is periodically checked/refreshed/pruned/whatever, so that may cause a CPU usage spike without any new books, which in turn would drain the battery a bit.


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