I think I have nailed it. I can now get my phone to do 27 hours of standby time at will. That's after having light battery drain, followed by a huge one, back to light and so on... So I've been where you are.
And here is the thing... Task manager and application manager are trash. They will not show you all running apps which in my opinion is highly misleading. Such tool should be limited to "clearing ram/closing all apps" if it cannot show what apps are actually running.
So my findings are:
#1 battery drain combo: Rogers Visual Voicemail via LTE (they are essentially mutually inclusive and deadly to your battery).
How have I discovered that? Well, upon being in both the 12-hrs/charge and 27-hrs/charge situations, I have hit the bottom with 12 hours per charge again and could not improve it. I tried closing all apps, enabling wifi (to stop LTE from kicking in) and still got 7% of drain per hour in standby (which is pathetic and drains the battery in 12 hours). One thing that caught my attention when I returned home was that despite Wifi being enabled and connected, the LTE sign was on... Then I looked in the notifications area and saw a message that sat there for the last two hours - Visual Voicemail is syncing messages. So VV was enabling LTE thus killing my battery since cell messages cannot be downloaded via wifi (i had no new messages anyway so the app was malfunctioning to begin with). I tried closing VV to no avail, it's not showing up anywhere! So I entered VV settings and deactivated the service... Sure enough the LTE sign went off and my battery charge from 100% after exactly 60 minutes = 0% (zero percent!). OK, we know it is an approximation but you get the point. The next day, the phone easily lasted 24 hours again! (with about 2-4 minutes of screen time per hour).
My second biggest drain came from Talkatone which showed some suspicious processor activity (4%). I believe talkatone is able to drain my battery at a rate of about 2% / per hou (first few hours), so that's already much worse than 0 ( LOL ).
Anyhow, I only need talkatone when I make phone calls so keeping it off is OK. Wifi should stay on (as LTE in my observations uses a lot more juice), kill & deactivate your visual voicemail and close all other apps. Charge the phone until full and leave overnight. You should see ~15-18% battery drain after 7 hour or so (assuming you are in wifi zone) and if wifi is available where you are during the day, you should be able to see 24-hr standby time with minimal use. By the way, that 24 hours is achieved with sync on, email, chrome and you name it apps running in the background.
And here is the thing... Task manager and application manager are trash. They will not show you all running apps which in my opinion is highly misleading. Such tool should be limited to "clearing ram/closing all apps" if it cannot show what apps are actually running.
So my findings are:
#1 battery drain combo: Rogers Visual Voicemail via LTE (they are essentially mutually inclusive and deadly to your battery).
How have I discovered that? Well, upon being in both the 12-hrs/charge and 27-hrs/charge situations, I have hit the bottom with 12 hours per charge again and could not improve it. I tried closing all apps, enabling wifi (to stop LTE from kicking in) and still got 7% of drain per hour in standby (which is pathetic and drains the battery in 12 hours). One thing that caught my attention when I returned home was that despite Wifi being enabled and connected, the LTE sign was on... Then I looked in the notifications area and saw a message that sat there for the last two hours - Visual Voicemail is syncing messages. So VV was enabling LTE thus killing my battery since cell messages cannot be downloaded via wifi (i had no new messages anyway so the app was malfunctioning to begin with). I tried closing VV to no avail, it's not showing up anywhere! So I entered VV settings and deactivated the service... Sure enough the LTE sign went off and my battery charge from 100% after exactly 60 minutes = 0% (zero percent!). OK, we know it is an approximation but you get the point. The next day, the phone easily lasted 24 hours again! (with about 2-4 minutes of screen time per hour).
My second biggest drain came from Talkatone which showed some suspicious processor activity (4%). I believe talkatone is able to drain my battery at a rate of about 2% / per hou (first few hours), so that's already much worse than 0 ( LOL ).
Anyhow, I only need talkatone when I make phone calls so keeping it off is OK. Wifi should stay on (as LTE in my observations uses a lot more juice), kill & deactivate your visual voicemail and close all other apps. Charge the phone until full and leave overnight. You should see ~15-18% battery drain after 7 hour or so (assuming you are in wifi zone) and if wifi is available where you are during the day, you should be able to see 24-hr standby time with minimal use. By the way, that 24 hours is achieved with sync on, email, chrome and you name it apps running in the background.
