[G3 Q&A, Help & Troubleshooting] svavartr:
I use and love LG G3 D855 international version

I almost went completely mental trying to discover and fix what caused my battery to drain from 100% to zero in 5-6 hours with about 1 lame hour SOT. Believe me i tried freaking everything, from obbsessing about wakelock (everytime I killed one i was rewarded with 4 or 5 new ones in return) to installing multiple battery savers every week to try if they worked, Most do not! I searched XDA Threads and reddit, i even started few threads asking for help, nothing worked. Until I changed my thinking and demands for useless (but cool) tweaks.

Here's what i did, or did not do :

I installed CloudyG3 Rom version 1.2 I got rid off all battery savers/tweakers, i did not install Xposed Frameworks (witch was the hardest one to get rid off because im heavily used to some tweaks available there) I know Xposed by itself does not drain battery, but i've learned that many of the tweaks are not coded good enaugh so they drain alot. (while others are perfect and work fine) but i don't feel like sort out the good from the bads, i now know that all of them can be lived without.

I also got rid of all battery monitoring software, many of them do take to much juice by monitoring my system.

The rom is rooted, i got "superSU", "Busybox", "titanium backup", "root explorer" and some other root apps for the basics. I leave all system or ui tweaks apps out, they're easy to live without and some drain alot of juice. I even skipped installing Greenify, wich has done amazing job on my previous devices, but somehow was not on my G3 (i know i couldn't belive it myself)

I on the other hand have Android device manager active and screen on "auto" with the slider in full. For the first week or two i had all systems on, i had wifi and data both always on and gps and location services, i want to be able to use the device to it's fullest, but that can cost juice. It was fine, i got about 2.5 - 3 hours screen on time over 15-17h period, witch did not fully satisfy my needs, though it was a step up from the 1 - 1.5h I had before.

So i figured to use tasker to automate everything i liked, but i don't find tasker user experience good enaugh, it's too much too learn and get right for a "player" like me. So after googling for few minutes i installed app called AutomateIt Pro (there is a free version but i bought it to get more triggers, like cell tower based trigger. AutomateIt Pro i use to turn on wifi and disable data when im home or at office, and when i leave those places it does the opposite (wifi off, data on) , I leave Location disabled but make it enable when i open apps that uses it like maps, (and of cource disable it again when apps closes) and if i loose the phone i can enable both gps and sounds by sending a password by sms, that way i can use Android Device manager if it's gets lost.

I have few more tweaks there but those are the ones that saves my battery, the others i use for my special needs like disable screen rotation unless apps of my choice are open. and some others probably not worth to mention. I find this app easy to use and does it's job well. There are actually many apps that can do the same, like Tasker, Trigger and some others, but this one worked for me.

The results are quite good, i get 4-5 hours screen on time over 17-20 hour period, thats more than a day so usually it's about 30% battery left when i plug it in and go to sleep. the 4-5 hours suit my usage so im really happy after trying almost every trick in the book, and even trying to discover new ones to fix my horrible previous battery life.

In ending i want to say i am no expert, I know quite little about Android insides or how it works. But i´m a heavy user with more knowledge of the basic stuff than the people around me. Feel free to try out what i did, but i can in no way guarantee they will work or if they are useless. I share all the stuff that i did, some obviously are helping while some are not and did not need to be done, but my device is now as i like it to be and i don't have the time to go into finding out witch ones are doing the trick. All the changes i did are pretty basic so you shouldn't be able to damage anything, unless you're an idiot of course :)

Sorry about my english, it's not my first language and it gets rusty when not used regularly.

I hope this way to long madness will help those in same problems that i was in....