Why does my iPone suddenly have horrible battery life?

September 24, 2012 8:07 AM

What could cause the sharp drop in battery life for my iPhone 4S? Even if fully charged, it will deplete within 5-6 hours of idle time.

I noticed this problem about ten days ago when my iPhone did not wake me up. The experiment repeated the next evening, with a fully charged battery, resulted in a drained phone the following morning.

I have made no changes to the phone that correlate with the suddent drop in battery life. I have been running iOS 5.1.1 since last May (jailbroken). I've restarted, resprung, and made every effort to ensure that no battery-draining apps are running in the background. No success. Extensive Googling has yielded no solution.

I suspect that this is probably an issue with the battery itself that will require replacement of the phone. However, I am interested to learn if there are any last-ditch efforts I can take before I need to talk with the geniuses.

Thank you very much.

posted by Tanizaki to technology (13 answers total)

Have you enabled the "Ask To Join Networks" setting under WiFi settings? I had dramatically better battery life once I disabled that feature.
posted by Rock Steady at 8:13 AM on September 24, 2012

Yeah, this is almost certainly a change in either network settings or network environment that the Phone is running down the battery using a radio at max power.

Try throwing it in airplane mode and see if the battery does its dropping, if you have time to experiment.
posted by Sunburnt at 8:15 AM on September 24, 2012

Note that if it is your battery, you don't need to replace the entire phone. I replaced my wife's 4s battery this weekend and it was quite easy. Turn off, remove sim card. Remove 4 screws. Pry/lift up old battery. Insert new. Close up.

There are many videos on youtube you can follow step by step.
posted by Quack at 8:25 AM on September 24, 2012

I have noticed a sharp drop since I downloaded iOS 6. I downloaded the app Carat to try to figure out exactly what is causing it. So, try downloading that app. It takes about a week for the data to be analyzed.
posted by hazyspring at 8:33 AM on September 24, 2012

Try turning off applications running in the background.

A little known (at least it seemed that way to me) function of the home button is that if you push twice a tray will pop up on the bottom of the screen with four apps. Swipe and you'll see all the programs that are running or at least loaded. Long hold one of the icons, they begin to "vibrate" and you (confusingly) get the delete button in the upper left of the icon. Click on it and the icon disappears. This doesn't delete it, just stops it from running in background. Some programs do more - drawing battery, slowing internet connection - while running in background than others. Some load with startup, some just stay there once you've opened them. Worth trying.
posted by RandlePatrickMcMurphy at 8:50 AM on September 24, 2012 [2 favorites]

I was having the same problem a little while ago. I did what RandlePatrickMcMurphy described above first, then restored my iphone through itunes. One of them worked and it's back to normal.
posted by shimmer at 9:27 AM on September 24, 2012

Free apps kill smartphone battery life

Those free apps like Angry Birds, Instagram and Tiny Wings may be loads of fun, but they suck the battery life out of your smartphone by tracking your geographical location, sending information about you to advertisers and downloading ads.

posted by jamjam at 10:09 AM on September 24, 2012

In my experience, iOS 6 caused an improvement with battery life, and it supposedly fixes some battery-life related bugs from iOS 5. It may or may not solve your problem.

What I have done in the past to track down battery issues is to run Apple's Instruments app, which is part of XCode, and connect it to the iPhone and see if anything is using excessive CPU. This is how I tracked down a batter issue that turned out to be T-Mobile's Bobsled app going bonkers. You might need a paid Apple developer account to use it with an iPhone, though, I'm not sure.
posted by fitzage at 10:17 AM on September 24, 2012 [1 favorite]

Do you have the Facebook app, and did you just load one of the updates? If so, you have to go back and turn off push notifications again--every app update restores push notifications to a default of all on, and will destroy your battery life.

Signed,
Learned The Hard Way When I Upgraded One Night And My Phone Was Dead In The Morning So My Alarm Didn't Go Off And I Awoke, Still In Bed And Unclothed, To The Sound Of My Parents Ringing The Doorbell At Noon.
posted by jesourie at 11:10 AM on September 24, 2012 [3 favorites]

Seconding Instruments. When I ran it I was surprised to find the Location Services daemon (locationd) eating a bunch of CPU, even on a fresh restart. If you go to Location Services in the Settings app and scroll down to System Services, you can turn off a bunch you don't need, and that fixed it.
posted by iotic at 12:41 PM on September 24, 2012

Something similar happened to me a few months ago on a 4s; I was going crazy trying to think of the most recent updates I had made and experimenting with airplane mode (yes, it saved battery life). Eventually I mentioned to someone (who happened to work for Verizon) that my phone had been acting up and where I usually only had to charge it once a day but that it felt like it was spending more time on the charger than in my hand. I might be botching the explanation, but basically, he told me that because we weren't in a big city my phone was having to work harder to find the 3G signal than it would if I were at home (big city). Of course when I returned to the city, my phone was back to "normal."
posted by MuckWeh at 12:38 PM on September 25, 2012

To piggyback: I almost posted this exact question. None of these solutions have worked for me so far (yet). Weird that so many iPhone 4S users would have the same issue around the same time. One friend got a replacement phone. I've noticed that this correlates with a bug I have where sometimes the battery percentage does not display in the status bar. Any other suggestions?
posted by mattbucher at 12:23 PM on October 10, 2012

To update, I had tried most of these suggestions before posting the question.

I am really not thrilled about the idea of a replacement phone because I will lose the jailbreak, but the current situation is not sustainable. I think I have done everything that I can as an end-user, but would welcome any other suggestions.
posted by Tanizaki at 7:06 AM on October 11, 2012