Iphone 3GS with iOS4 – Important info

I learned something really important about the new iSO4 upgrade on an iPhone 3GS.  My phone began running totally out of battery in 6 hours or so.  I reset it and recharged it and it did it again.  When I looked at the Usage – Settings – General – Usage I was seeing in the Time since last full charge area — Usage 5 hours – Standby 5 hours.  The phone was in 100% use until it killed the battery.

Here is what 3GS users need to know.  The iOS4 software does not work like we are all used to.  With the older 3 series OS when you push the home key it closes the App and goes back to the Apps screen.  What is different with iOS4 is this – when you use the Home key the screen looks the same – you go back to the Apps page(s) however what is really going is is the program is not stopped it is still running – you can see what is running by clicking the Home button twice – the App “lifts” up and you will see a window with Apps that you can scroll.  You click on the App in this window and it opens – Apple calls this multitasking – it is really task switching and is fine for most Apps.

So what was killing my battery on my 3GS phone???  Apparently some programs do not go to a suspended mode but rather keep running – programs that use the GPS are the ones to watch out for.  The new OS will tell you what is using GPS or location finding with a little purple check mark on the upper left beside the battery indicator.  That little purple check mark is important!!!  When you want to quit a program that has this purple check mark you will need to double click on the Home button and touch and hold the application icon until it “shakes” and then click on the minus sign.  This will stop the program.  It appears some programs will keep the GPS turned on when and continue to upgrade your location if you just press the Home button.  With the GPS turned on you battery will discharge very quickly – you phone will totally die in a few hours rather than run all day.  Turning the phone off and then back on will not change the status of these programs.

I am not certain which programs were killing my batteries but some that turn on the GPS are Maps, Trapster, Where, Around Me, pUniverse,  and others.

What I have learned is Apps that have the blue check mark up by the battery indicator need to be shut off from the Task Switching window – once turned off the will go away from the Task Switching window. 

So if all of a sudden your battery life is cut drastically down go to the multitasking window and see what is running.  Kill by holding down the icon until it “shakes” and then tap on the minus sign.

When you do this you battery life will go back to normal.