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From: Arfa Daily on 28 Jun 2010 20:23


"Jeff Liebermann" <jeffl(a)cruzio.com> wrote in message
news:j7ih26deuf9d1nup0lm7rq2s2ffc2smc5k(a)4ax.com...
> On Sun, 27 Jun 2010 09:36:01 -0700, Jeff Liebermann <jeffl(a)cruzio.com>
> wrote:
>
>>I ran a crude test last night. At midnight, my iPod Touch 2G showed
>>97% battery charge (using iSystemPro). 9 hrs later, it's at 89%.
>>Notification is set to check my stocks and eBay items every 15 minutes
>>via Wi-Fi.
>>
>>Here's another app to help run the battery down:
>><https://www.ihoundsoftware.com/ihound/template/iPhone.vm>
>>Much like LoJack for iPod Touch, iPad, etc. I just installed it.
>
> Argh. I installed iHound to send their server my location every 10
> minutes. The default was 3 minutes. I left iHound running overnight.
> The battery went from 97% to 32%. Ouch.
>
> I don't think it's Notifications that are sucking the battery power.
> Methinks the problem is leaving an application running that uses
> notifications or just CPU cycles when the iPod Touch is in standby. I
> usually display the desktop before turning off (actually standby)
> mine, so I haven't had much experience with what an application can do
> to the battery level if left running.
>
> --
> Jeff Liebermann jeffl(a)cruzio.com


No apps were running to the best of my knowledge, when the problem was
occurring. I installed an app that monitors the system processes, as well as
a lot of other things like the battery, and checked what the state of play
was before putting it to sleep. It showed the processor as being (typically)
96 - 97% idle. There was one app that *wanted* notifications access, but the
app was not running - or at least it wasn't running in the foreground.
Nothing had changed with this app or the way it was loaded, and it had not
caused a problem before. Maybe iOS 4 gives it what it wants in the
background. I guess this may be a bug, and because of that keeps the wifi
running pretty much continuously. I don't know where in the unit the wifi
module is located, but certainly, the back of the case was warm enough to
just about feel, up near the top. It never had been before, and isn't again
now.

I have actually deleted the app that wanted notifications access now, so it
might be an interesting experiment to turn notifications back on. I guess I
could also wave the unit at my spec anny, and see if there is any obvious
wifi activity from it, when it's asleep.

Arfa

From: Jeff Liebermann on 28 Jun 2010 21:06
On Tue, 29 Jun 2010 01:23:13 +0100, "Arfa Daily"
<arfa.daily(a)ntlworld.com> wrote:

>No apps were running to the best of my knowledge, when the problem was
>occurring.

So much for that theory.

>I installed an app that monitors the system processes, as well as
>a lot of other things like the battery, and checked what the state of play
>was before putting it to sleep. It showed the processor as being (typically)
>96 - 97% idle.

That's what you'll usually see. The iPod Touch does not support
(much) multitasking (thank you Apple) so the only application that's
really able to run has to be in the forground and running. An
application can be installed, but unless it has Steve Jobs personal
permission to run in the background, it's not going to burn any CPU
cycles.

>I don't know where in the unit the wifi
>module is located, but certainly, the back of the case was warm enough to
>just about feel, up near the top. It never had been before, and isn't again
>now.

Looking inside:
<http://www.ifixit.com/Teardown/iPod-Touch-2nd-Generation/586/1>
the wi-fi chip is near the top, next to the antenna:
<http://s1.guide-images.ifixit.net/igi/a11UeKjfQfuIIrHD.huge>
next to the gold test coax connector. Mouse over the Broadcom chip in
the right hand photo above the "Step 10" label.

>I have actually deleted the app that wanted notifications access now, so it
>might be an interesting experiment to turn notifications back on. I guess I
>could also wave the unit at my spec anny, and see if there is any obvious
>wifi activity from it, when it's asleep.

A passive Wi-Fi sniffer (Kismet) might show more. Spread Spectrum is
difficult to see on an SA. If Notification is on, you should see some
traffic when it wakes up. However, if you REALLY want to run the
battery down, turn off you wireless router at night. The iPod Touch
will try to find something with which to connect. Not finding any
open access points, it will go through the list of SSID's heard, thus
taking more time, and much more battery power.



--
Jeff Liebermann jeffl(a)cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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