But there's no point of comparison, right? There's never been multitasking on the iPhone. So, we have no idea whether it saves batt life.
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Battery Problems with 3.0? Try the "Battery Logging" Setting to gather Logs
- Thread starter skoops
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But there's no point of comparison, right? There's never been multitasking on the iPhone. So, we have no idea whether it saves batt life.
Not even close. Having multiple apps running in the background will not only destroy battery, but suck up the CPU for active apps.
PNS is the ideal solution for those who want background services. You should be able to have basically unlimited number of background services with only one connection. Obviously the more notifications you pass, the greater the battery drain, but it seems reasonable that if an app is not passing a notification, there is no additional penalty.
The biggest thing with push notifications is if you have sound and alert on. I would imagine having to generate a sound and turn the screen on takes more power than just changing the badge.
As Apple relayed at WWDC (or the March dev conf) - they did the testing themselves and found that apps running in the background caused even more than a 21% batter hit. I do not remember the exact number, but it was high. If the 21% hot for Notifications (e.g. Push) turns out to be true - that may be too high of a price to pay for me. Maybe when Facebook adds Notifications - maybe I will turn it back on.
Well here is a snippet of time:
The rest is in the zip file below.
Code:
Thu Jun 25 09:55:49 2009 (sleep)
Thu Jun 25 09:56:00 2009 (wake): Battery level = 82 [3990] (low = no, critical = no, charging = no) Call active: no
Current drain: -217 mA
Fully charged: no
Wake Reason: menu
No Power Assertions
Usage: 01:58:52 Standby: 04:04:35
Frontmost Application Identifier: SpringBoard
Next Scheduled Power Event:
PersConn-apsd-com.apple.apsd-push.apple.com
Scheduled Wake or Power On
2009-06-25 10:00:55 -0400
WiFi: Disassociated
Bluetooth: OFF Nike: OFF BTAirplaneMode: OFF Discoverable: OFF Connected: NO
Thu 06/25 09:55:49 (CommCenter:27): There are 3 assertions for PDP context 0:
Thu 06/25 09:55:49 (CommCenter:27): PersConn-aosnotifyd-com.apple.AOSNotification
Thu 06/25 09:55:49 (CommCenter:27): PersConn-MobileMail-FDFA78BD-6B8E-4CD6-AF7B-4AB1DD5C8A1E
Thu 06/25 09:55:49 (CommCenter:27): PersConn-apsd-com.apple.apsd-push.apple.com
Thu 06/25 09:55:49 (CommCenter:27): Telling PDP context 1 to go inactive.
Thu 06/25 09:55:49 (CommCenter:27): Telling PDP context 2 to go inactive.
Thu 06/25 09:55:49 (CommCenter:27): Telling PDP context 3 to go inactive.
Thu 06/25 09:55:50 (CommCenter:27): Deactivated PDP context 1 that supports connection types 0x2
Thu 06/25 09:55:50 (configd:20): network configuration changed.
Thu 06/25 09:55:53 (CommCenter:27): Telling CSI to go low power.
Thu 06/25 09:55:53 (CommCenter:27): CSI can enter low power, so now telling to do so.
Thu 06/25 09:55:53 (CommCenter:27): Will sleep. Heard from CSI in 0.00474101 seconds
Thu 06/25 09:55:54 (kernel:0): AirPort: Disabled AppleBCMWLAN (link 1, sys 1, user 1)
Thu 06/25 09:56:00 (kernel:0): AppleBCMWLAN::setPOWER() [kernel_task]: Setting power state to 0
Thu 06/25 09:56:00 (kernel:0): AppleBCMWLAN::powerOff Ready to power off
Thu 06/25 09:56:00 (kernel:0): AppleSynopsysOTGCore::notify : currentMode and calling driver mode doesn't match
Thu 06/25 09:56:00 (kernel:0): AppleBCMWLAN::setPowerStateGated() : Powering Off and sleeping
Thu 06/25 09:56:00 (kernel:0): AppleBCMWLAN::powerOff Ready to power off
Thu 06/25 09:56:00 (kernel:0): AppleMultitouchN1SPI: disabled power
Thu 06/25 09:55:54 (kernel:0): System Sleep
Thu 06/25 09:56:00 (kernel:0): pmu wake events: menu
Thu 06/25 09:56:00 (kernel:0): System Wake
Thu 06/25 09:56:00 (kernel:0): AppleBCMWLAN::setPowerStateGated() : Powering On
Thu 06/25 09:56:00 (kernel:0): AirPort: Enabled AppleBCMWLAN (link 1, sys 0, user 1)
Thu 06/25 09:56:00 (kernel:0): AppleBCMWLAN::setPOWER() [kernel_task]: Setting power state to 1
Thu 06/25 09:56:00 (CommCenter:27): Telling CSI to exit low power.
Thu 06/25 09:56:00 (kernel:0): AppleMultitouchN1SPI: enabled power, scheduled bootloading
Thu 06/25 09:56:00 (kernel:0): AppleD1755PMUPowerSource: AppleUSBCableDetect 0
Thu 06/25 09:56:00 (kernel:0): AppleD1755PMUPowerSource: AppleUSBCableDetect 0I just downloaded the battery log info from Diamond and scrolled to the bottom...looks like there is no battery drain (-5ma) when the battery is on the charger. I am getting a 76ma drain while it's at 100% and on the charger. Am I correct to think this is a problem?
Actually a positive drain number indicates charging. The negative number shows an actual drain. So in my case the phone was 100% charged and it started to do the float charging (where the unit discharges to a certain point then recharges).
Thanks Diamond. How as your battery life been in the past few weeks since we've spoken? Has going through the charge cycle a few more times increased the life? What's your usage now? My average is about 6 hours on 3G with Push email/notifications on, and location services on.
It run concurrent to my usage pattern. On days where I use a lot (internet movies and tv shows) my battery life is short. I will say I haven't had it die on me yet. I think I get about the same amount of usage, with same settings as you.
can this be modified for iOS4?
The iphone configuration utility refuses to install this on my iPod Touch 2G running iOS4. Do you have a version for iOS4? or can you suggest what needs to be changed in the XML?
FWIW, the battery drain may(?) be due to persistent wifi. There are entries in the log file like this:
Sun Aug 22 13:46:06 unknown kernel[0] <Debug>: AppleBCMWLAN:
owerOff(): We are associated and Wake on WLAN is enabled, wifi is staying up!
Any ideas how to disable persistence? (other than airplane mode)
The iphone configuration utility refuses to install this on my iPod Touch 2G running iOS4. Do you have a version for iOS4? or can you suggest what needs to be changed in the XML?
FWIW, the battery drain may(?) be due to persistent wifi. There are entries in the log file like this:
Sun Aug 22 13:46:06 unknown kernel[0] <Debug>: AppleBCMWLAN:
owerOff(): We are associated and Wake on WLAN is enabled, wifi is staying up!Any ideas how to disable persistence? (other than airplane mode)
The iphone configuration utility refuses to install this on my iPod Touch 2G running iOS4. Do you have a version for iOS4? or can you suggest what needs to be changed in the XML?
FWIW, the battery drain may(?) be due to persistent wifi. There are entries in the log file like this:
Sun Aug 22 13:46:06 unknown kernel[0] <Debug>: AppleBCMWLAN:
Any ideas how to disable persistence? (other than airplane mode)
Turn WiFi off when you aren't going to use it for long periods of time.
I was under the impression that Persistent WiFi was only active when plugged into a power source. Is that not the case?
nope. FWIW, you can get an idea what's happening by bringing up the free app called BatteryGraph and then putting the Touch to sleep. If you leave it that way overnight and then wake it up in the morning, the graph shows a steady decline from 100% to 75%.