Does my Kindle 3 even need to sleep?

[akz28]

Greetings all.

I thought I read on one of the threads that one of the reasons why the battery life is so good on the Kindle, is because once the screen is displayed, the device does not need any power to maintain it. Power is only needed when a change is made (changing a page, going to a menu, etc. )

If that is the case, do I even need to put my Kindle to sleep when I am done reading for the night?
If wireless is off, will it draw power if I just leave it on the same page until the next time I go to use it

[Basilius]

Greetings all.

I thought I read on one of the threads that one of the reasons why the battery life is so good on the Kindle, is because once the screen is displayed, the device does not need any power to maintain it. Power is only needed when a change is made (changing a page, going to a menu, etc. )

If that is the case, do I even need to put my Kindle to sleep when I am done reading for the night?
If wireless is off, will it draw power if I just leave it on the same page until the next time I go to use it

It will go to sleep itself after 10 (? 15?) minutes or so.

The primary reason it does this is to minimize the (granted, small) power draw required for the buttons to be responsive. When it sleeps, it doesn't have to monitor the buttons.

And the battery will last for a long time with the Kindle in that state.

[leungss]

it needs very little power to display the text doesn't mean it draws no power.  And it will go to sleep after 10 mins whether you like it or not.  There is no option to turn off the sleep mode as far as I know.

[history_lover]

it needs very little power to display the text doesn't mean it draws no power.

Doesn't that mean it still uses the same power to display the screensaver? I assumed the "saverscreen"/sleep mode is actually just a keylock.

And it will go to sleep after 10 mins whether you like it or not.  There is no option to turn off the sleep mode as far as I know.

There is a way but it involves messing with a code or something - it's more like a hack.

[Kindleing]

Doesn't that mean it still uses the same power to display the screensaver? I assumed the "saverscreen"/sleep mode is actually just a keylock.

I don't think so.  Sleep mode shuts down wifi on my K3 even if it is on at the time it goes to sleep.  I suspect it also shuts down most processor functions including watching the keyboard for key presses.  Sliding the on switch wakes up the processor to pay attention to key presses again.  Apparently a timer continues working because it is supposed to download subscriptions even while asleep, but I don't have any so I haven't verified that.

However, I have let my K3 go to sleep with wifi on and connected, and then sent a book to it.  The book isn't delivered until the K3 wakes up again.  When it wakes up it syncs and downloads anything waiting.

Wally

[history_lover]

I suspect it also shuts down most processor functions including watching the keyboard for key presses.

Which is why I called it a keylock. I don't doubt it may save a little power here and there in sleep mode but it's not saving power on the display because it still has to display the "screensaver".

I don't know what to make of the wifi issue though - there was a discussion about this not long ago. I pointed out the same thing you did, that when I send a book or sample to Kindle while in sleep mode, it doesn't download it until I wake it up but others insisted they get subscriptions while in sleep mode and suggested that I wasn't giving it enough time to download.

[Ann in Arlington]

Subscriptions definitely come down while the Kindle is asleep if the wireless is turned on.

Now. . .it may work differently with the K3 which uses WiFi as the first default.  BUT, on my DX. . . I turn it on in the morning and turn on the wireless. . . .then I play for a while on KindleBoards. . .like now.  I put it back to sleep while I'm on the computer and when I wake it up a half hour later my daily issues will be there . . . even before the wireless icon indicator has come up to speed and reported the connection.

I think I have had books come too, when I still had my K1.  The wireless with that relatively drew a lot of power so, though I'd buy books nearly daily, I'd only turn on the wireless once a week or so when I plugged it in overnight.  When I did that, the new content was definitely on the Kindle when I woke it up the next morning.

With the K3. . .if I'm sitting here and buy a book I turn on wireless. . .which is WiFi and talks to my home network. . .and the book is there nearly instantly.

I have also noticed, though, that, if I leave the wireless on and let the K3 fall asleep. . . . books I then buy will be there on the device when I wake it from sleep.  It sure seems like they downloaded while it was sleeping, though I suppose it's possible it's so fast that it did it immediately I took it out of sleep.  But, again, I feel like they're there before the indicator is fully awake and reporting the connection status. . .but I admit I've not paid close attention.

Anyway. . . .I think the wireless is still active while the Kindle sleeps. . . .but I don't think it's, necessarily, constantly pinging the servers, to see if something needs to come. . .probably pre-set intervals or something -- probably not more often than every few hours and maybe only once a day.  And the WiFi may work differently than 3G.

I also suspect that there's a script it runs when you wake it up:  I'm awake!  Wireless is on! I should check for new content.  Which may be why, in some cases, it seems everything downloads when you wake it up.

As to the display. . .no matter what's on the screen, essentially NO power is used to display it.  So it doesn't really matter if it's a page of text or an image, or blank.  While reading, power is used when you 'turn' the page.  Sleep mode does lock the keys. . .which, as basilius suggests, will save power as it doesn't need to monitor whether something is being pressed.

[Elk]

Electronic ink only consumes power when changing its display.  Thus, an e-reader can continue to display the same text/picture without using any energy.

Just like an open physical book.

[icanhaskindle]

Sleep mode isn't so much about saving power as it is about locking the keys so you don't accidentally turn the page and lose your place as you put your Kindle away.

[Kindleing]

I think I can now confirm that my K3-wifi-only does not download books while sleeping, even though wifi was on when it went to sleep.  I ordered a free book earlier today and set it to download to my K3, but I hadn't turned it on since placing the order.  After reading the latest posts in this thread I went to the "Manage your Kindle" page and the book still showed as "Pending".  I turned on the K3 and watched as it woke up.  After a couple of seconds it flashed a message that something downloaded, and the main page refreshed and the new title was listed.  I immediately refreshed the Amazon "Manage your Kindle" page and the book showed as "Delivered".  I think the immediate change from "Pending" to "Delivered" confirms the book didn't download until the K3 woke up.  I have no idea how other models behave.

We know there is an internal timer that keeps the clock accurate, so it probably knows when to wake the Kindle and download subscriptions.  I don't have any, so I can't verify that.  The one thing that puzzled me earlier is the 3.0.1 update seemed to have download while sleeping.  Maybe Amazon can send a wake-up call to the Kindle if they want to push a download.  That would also track with Kindle customer service asking people to leave their K3's wireless on during some of the earlier troubleshooting that was going on.

I have left wifi on since receiving my Kindle a month ago because I wanted to make sure everything is ok.

Wally

[Elk]

My K3 will download documents sent to free.kindle.com while asleep. 

I have Calibre send it various news feeds on a regular basis.  The new periodicals will be on my K3 when I wake it up.

[Tatiana]

When I spoke with the Kindle Specialist Technician yesterday re: battery drain, he told me that I should just let my Kindle sleep and not turn it off when I am finished reading.  There really isn't any reason to turn it off when not reading.

[Tip10]

I believe that the wireless on a K3 either must stay active or must have some periodic wake up/poll function while asleep. 

Reason I say this is because our K3's WILL update firmware overnight while asleep -- for this to happen wireless must be active -- either via periodic poll or be held active while asleep. 
I believe (and at this point its only my opinion) that its done by periodic poll. 
It could also, conceivably, be done by doing housekeeping activity before allowing the WIFI to sleep (i.e. once device goes to sleep do a housekeeping poll asking if updates are such are available and downloading them and then allowing the device to go "deeply" asleep and shutdown wireless).

At this point I believe the following to be true:

For 3g devices if whispernet is on periodicals and such will be delivered regardless of whether the device is connected to your wifi network (provided, of course, there is 3g coverage).
For WIFI only devices if whispernet is on AND the device is connected to the WIFI network when it goes to sleep periodicals and such will get delivered to the device while it is asleep.

The only exception to this might be with networks that are configured with an inactivity timeout. (I know where to set mine, can't remember what its set at but do know that my K3 stays connected when asleep).
If the inactivity timeout is inside of the periodic poll of the network performed by your Kindle than the network will disconnect the Kindle and it would have to reconnect upon waking up. (i.e. if your network timeout is set to 45 minutes and the Kindle polls once an hour your network will disconnect the Kindle and periodicals, updates, etc will not come down after that until it reconnects to the network upon wake up (which it does automatically if whispernet is on).

The above is all predicated on the following statement from the K3 Users Guide:
Tip: Your Kindle will also go to sleep by itself after ten minutes if you are not using it. If your Kindle had wireless on prior to going to sleep, it will continue to receive your regularly scheduled subscriptions while in sleep.