Battery drain in standby

Thanks Lawrence Finch, that was the solution for me, i was very desperate for this problem. and now i don´t have any battery issue, everyting is normal again, thanks...

Often applications fail proper installation and a process can hang, causuing repetitive instruction calls (even in standby). With such a process continuously running on your iPhone, the battery drain can be significant - up to 25% or more in an hour. Here are a few solutions that have worked for me (it's happened to me on three separate handsets of the iPhone):

1) Do a hard reset - Hold the home and sleep buttons down together for approximately 10 seconds until the phone turns off. Wait a few second, then repeat to turn it back on. THIS WILL NOT ERASE any of your data or lose any of your setting, rather just a flash memory reset.

2) If that does not solve the problem, follow the procedure suggested by Lawrence Finch:

1. Under Settings, go to Mail/Contacts/Calendar - tap the name of the Exchange account. You will see 3 switches. Turn them off (repeat for each account), then back out of Settings. Do not turn off PUSH; only turn off the 3 switches. You may receive warning messages - go ahead and accept these - this data will be restored from your accounts once the switches are turned back on.

2. Open the apps one at a time, first Mail, then Contacts, then Calendar so these apps apply the changes.

3. Hold the home button for a few seconds and close all multitasking apps,

4. Turn off your phone, wait a few seconds, then turn it back on,

5. Go back into Settings and turn the 3 switches back on.

Usually the hard reset will solve the problem on its own, but the mail reset may be necessary in cases where the mail application is causing the process error.

Good luck! 🙂

This seems to be a software problem crossing many fronts.

Some users claim that shutting off Location Services based Time Zone support fixes the problem. No luck for me.

Others seem to be of the opinion that it only impacts iPhone 4S users. Also incorrect.

I do agree that it seems definitively linked to iOS v5.0.1 on many devices and it apparently manifests itself in several different ways.

I replied to your post as I am in the same situation. I am synched to an Exchange server for mail. I can have all services (mail, contacts, tasks, calendar, etc) enabled as long as I don't enable PUSH for the mail retrieval option. If I enable PUSH I must disable the calendar synching or the battery will drain itself in a matter of a few hours. This is repeatable and incontrovertable. No problems with any other Exchange based PUSH services...only calendar.

I have wiped and restored iOS. I have removed accounts and recreated with multiple power cycles in the process. I have disabled Location Services. I have removed all Cloud services. I have followed the instruction set above in this thread to a tee. No luck.

In my opinion nothing short of the next release of iOS 5 will fix this and only then if Apple pays attention to the fact that this problem exists on several fronts and all of them need to be addressed and soon.

To take this out a step further I've refollowed the instruction set above and this time only reinitiated calendar services under the Exchange account. Battery is draining at a constant rate of about 20% per hour.

The problem is obviously ActiveSync and Calendar related and there doesn't seem to be a solution.