Battery drain issue iPhone 4S - iOS 9.3.5

Hello people,

since iOS 9 I have been getting huge battery drain on my iPhone 4s.

The main issue is that the usage times are close to standby times - usage is about 2/3 of the standby !

The Apps installed on my phone are:

WhatsApp, Telegram, BatteryLife, Instagram .

In that fashion, my phone goes from full to 0 in about 10 hours, no matter if apps are used or not.

Any solutions?

I reset my phone, calibrated battery, did a hard-reset and enabled the following in settings:

Settings:

1) Carrier -> Automatic: OFF

2) Notifications -> Calender,WhatsApp to OFF

3) General -> Background App Refresh to OFF for all apps

4) General -> Assists -> Reduce Motion

5) General -> Assists -> Increase Contrast -> Decrease Whitepoint to ON

6) Display brightness to 1/3, Autobrightness to OFF

7) Background -> ...-> Static

8) Privacy -> Location Services -> OFF

9) Privacy -> Diagnosis -> Don't send data

10) iCloud -> Calender, Reminders, Safari, Keys,Backup to OFF

11) iTunes & AppStore -> Automatic Updates to OFF

12) Mail,Contacts,Calender -> Push to OFF , manual FETCH instead

13) Battery -> % to OFF

14) General -> locktime -> 30 secs.

As said, if the phone is "sleeping" , the usage time is 2/3 of the standby time.

-mike