Q: possible multi step solution for poor battery performance

device: iphone 4s, 32 gb - initially restored from an iphone 4 backup.

problem: battery almost empty (20-25%) in the afternoon when device is being used (normally).

with the preceeding iphone 4 running ios 4.x.x the battery life was much better, around 35-40 % in the evening (same setup, same usage of device)

setting: setting up the device as a completely new phone is not an option for me: i have 174 apps installed, and i really use many of them, and many of them contain individual data which is not that easy to be backed up seperately for a manual individual restore.

also, i need to have push for e-mail, wifi and bluetooth turned on constantly, as i'm connecting at home and at work with wifi and in the car with bluetooth. also i am not willing to drop 3g, as i regularely use mobile internet, and i want speed. and i refuse to turn location services completely off, as i decided for the phone also because of the comfort of location services.

yes, i do close most of apps from the multitasing bar regularely.

i applied a few tricks on the device, and today my batterie's performance has indeed increased.
i can not nail it down to a single change of options, so i guess it's probably the sum of actions that did the trick.

• step 1, preparation
  in preparation, i startet to restore the device. for that, i turned off passcodes for the sim card and for the device - made a backup with itunes (device connected via usb) and then restored it. after restoring it, i immediately synchronised it in order to have all apps back in place. then re-applied passcodes and back upped the device again for security reasons.

• step 2, checking settings
  checked location services: like before, only services for network carrier and compass are active.
  checked push services. like before, push services are active only for apps where i really, really want (and need) push notifications.
  checked screen brightness, like before it was set to 55/60 %.

• step 3, applying changes to icloud settings
  deleted icloud-accounts (backed up ical and adressbook-data in advance on my mac). being a long time customer i had 2 accounts - one from my itunes store account, one from the former mobileme account. as accounts cannot be merged i have to live with this disadvantage.
  i decided to use one of these accounts for mail, calender, tasks, find phone and stuff and configured the other one online to forward mails only.
  then i re-applied the icloud acount i really want to use, activating (like in the former setup) everything except reminders, notes and photostream.
  deactivated icloud backup (like in the former setup).

• step 4, checking mail accounts
  checked mail accounts.
  like before, using just my icloud account with push-services plus another mail account configured not to use push but fetch mails every 30 minutes.

• step 5, applying changes to siri
  deactivated siri (sigh!)

• step 6, applying changes to backup settings/itunes
  deactivated backup via wifi for the iphone in itunes on my mac.

• step 7, reset/reboot
  closed all apps and did a soft reset of the phone by pressing power button and homebutton simultaneously until the device rebooted.

• step 8, voodoo (probably ridiculous)
  being honest, personally i feel this last step is voodoo, so maybe you can skip it. i used the device until the battery has around 15% of energy. referring to a tip in one of the threads i installed "battery doctor pro" from game lingo. closed all other running apps from the multitasking bar, and activated the maintain function (before that i changed the trickle charge time in the app's settings to 120 minutes). then started charging the device.
  disconnected it after around 6 hours.

results:

3 hrs standby (flight mode on): still 100% energy.

20 minutes for checking e-mails, surfing the web, downloading apps with wifi: 97% (before: around 92%)

20 minutes later, device was stand by, it had 95 %.

30 minutes ride by car, using the device without charging for audio playback via bluetooth, screen turned on all the time plus using active gps-location-service for one app running in the background – this left me 85% of energy when arriving. before performing the above steps the device had around 75% of energy left.

so - at least an improvement with maybe acceptable compromises.

nevertheless on the long run i feel that buying a full featured device which is only usable by not using it is simply not acceptable.

Hopefully, this helps.