My wife and I are having the same issue and we're still on Lollipop. Something is absolutely killing our batteries.

 

After the update, I've noticed a more significant battery drain, as well. Nothing life threatening, but I did go through about 40% in maybe 4 hours. Half that time, I was streaming audio, though, so take it FWIW.

 

After an OTA, you usually have to give it a few days or more to "settle in". For me, battery life is the same if not better, especially when I don't use the phone. I also use a combination of Greenify and SnapDragon BatteryGuru which help as well to control "stray" apps. I'm going to give it a few days to settle down and then I'm going to disable both and then see how Doze works, but so far, it appears to work great. Under stock, unrooted using Greenify and SnapDragon BatteryGuru, my battery would drain about 3% to 5% overnight. Last night, after upgrading to MM, my phone dropped only 1% in battery and the only change was upgrading to MM. I didn't do a factory data reset at all and performance has been just as good as it was before. Only change was it appears battery life on stand-by has improved to what I was getting on custom, debloated ROMs. I like that.

I doubt it killed your battery. If that is an old one, it could be going bad based on what you stated after you switched. But also, like I said, you have to give the system time to calibrate the battery and such.

As for the not automatically connecting, that's a security feature. A lot of what Marshmallow brings to the table is more security fixes. I believe the same goes for the external SD cards. I can no longer get to it using a generic /storage/external_SD mount point. It apparently now mounts it based on whatever serial number it gets when you format it. Since the external SD card is not very secure (any app could read data there), this makes it a bit more difficult to directly get access to it I believe. One option we don't have with the G3 is the ability to reformat the SD card to behave as internal memory. This basically makes the card unreadable except within the phone. Now that's an issue if your phone dies. Then you have no way to read the card and would have to reformat it, so there's good and bad with it. The good being that it protects whatever you have on the card so that only the phone can read it. The bad, as I stated, is if your phone dies, you have no way to get the data off the card at that point. This might show up in a later OTA if we get any more OTAs for this phone. Doubt I would use it though since I only use my external SD card for storing documents, pictures and music. And my documents are nothing with PI in them. Mainly PDFs of books that I like to take along to read if needs be.

MM probably won't be for everyone, but also, the Material design is not just driven by Android. it's driven by trying to make applications that will appear the same, regardless of how you access them, especially when it comes to HTML5 applications. It's not everyone's cup of tea, but it is what it is.

You can downgrade, but it requires knowledge of using TOT or KDZ files and could result in you bricking your phone if you don't know what to do. But, there are tutorials out there on how to do it on other forums. Do a Google search on "Flash Back to Stock - KDZ Method" and you'll get a link to the forum I'm talking about.

 

Since people have been complaining about lollipop battery drain for months, youd think marshmallow would be some what improved, but not worse!

 

(12/10/2016)

Update to my original post:

So my ultimate conclusion in fixing a battery drain (again, this is for people who have made their phones as efficient as possible in all other regards, without proof that it may be a hardware issue, i.e., battery itself is bad, but still have problems) is that you need to clean out old junk. After a factory reset, and having installed and uninstalled a number of apps, along with os updates, i began to get the drain again, after my factory reset, which worked for a couple of weeks. What fixed it, i'm almost certain for sure now, is clearing out the APP cache (from the settings menu, under storage - not system, dalvik cache via recovery). Doing a factory reset in essence clears out the cache in the process, so "seems" to be the answer- but contrary to my earlier statement (see below), you may NOT need a factory reset and only clearing the cache might work. You can also clean out the system cache via recovery just in case.

I'm not a programmer not do i understand how Android works, but it appears that whenever you install or uninstall apps, it must leave some junk files that have conflict somehow and it can drain the battery. I suppose not all apps are made/coded the same and it's reasonable to believe that they can have negative effects on your phone, as it must change some configurations that are left behind and not restored to normal when the app is uninstalled. This also may be true whenever an app that you still use has updates and such - so not limited to uninstalled apps only.

Anyways, it's been two weeks since i started to clear out app caches and the battery drain seems to be gone for good. Whenever i "feel" like my battery is losing more % (it may just be in my head, and it's not significant by any measurable amount) i just go to settings and clear out the app cache. Hope this helps.

-----

(Nov 15, 2016)

So if you are/were like me and have tried pretty much everything, looked everywhere (if you're looking at an old thread like this, you're probably desperate to find a solution), and have all the tweaks on your phone to save battery, and the advice people give about disabling wifi and bluetooth, and other obvious tips that annoy the heck out of you, and you've looked at the health of your battery (seems fine) and other hardware related issues, but your battery still drains here's the real truth.

YOU NEED TO DO A FACTORY RESET OR DATA WIPE.

I've been personally guilty of not facing the same inevitable fact in the past, but whenever you have an OS update or when things just don't seem to work all of sudden as it did before, there's a conflict with some of the old "stuff" in your phone and you need to clean that out. It's not the update or the new OS that's the problem - it's the conflict with the old junk in your phone that's causing the issue. My phone used to drain overnight (where when i wake up the phone is dead), but now it is at 85% when i go to sleep, 85% when i wake up 7-8 hours later. And that's with wifi off during sleep, data/bluetooth off. You won't get the same result unless you have the same [root] tweaks that i've made in other areas, but regardless, it's not gonna go dead overnight.

I know - it seems scary and it may take some work to get it back to where you had it, but think about all the time you spent trying everything else. Just bite the bullet and get it done - i promise it will solve your battery issues.

You don't need to wipe "system" or your internal/sd cards (don't wipe these, in fact) - just wipe "data", "cache" and "dalvik". It will throw you in to the original Google/Android phone setup steps, but just go through them. Have google backup or use apps like Titanium to back up every little thing on your phone (like msgs) beforehand. If you have a launcher, you can make back up of that too. Well, this part you probably can figure out.

 

Dont own this phone anymore.... but I did 2 factory resets and nothing worked. Well it did stop my phone from being a pocket seat heater, but nothing as far as battery life.

Moved on to an S7 Edge and never looked back....

 

Well, if your phone got hot, that may have damaged the battery and the phone as well. In my case, the battery was just fine (no bulging or heat) and even though i've tried all sorts of possible solutions (everything from uninstalling apps to killing background processes, to battery calibrations, etc), it would start to drain hard around 1 AM and it would be dead or on power save by morning.

I just wanted to post here because it seems like many folks post that they've tried everything and a data wipe is the last resort, but may in fact save a lot of grief and time if they tried the wipe first. I HAD to do it because my phone got stuck on boot (due to Super SU update which messed up) and i had to reinstall the OS and thought i might as well try the wipe/factory reset as well. Turned out that it fixed my battery woes, even if i lost some data (which i didn't have a chance to back up, since the phone froze).

Now if i can just fix the damn echo on the speakerphone...

 

Echo is a pain yeah.

I know in my case, the problem was with the phone somewhere. I even replaced the battery, and it still drained super fast. this was post factory reset.

 

download Kernel Adiutor and battery calibration run kernel adiutor first and set your cpu to conservative or power save and do the same for the gpu (set both to apply on boot) then open and run the calibrator (the calibrator will also tell you the health of your battery and how much charge is going in from the charger)

 

Nice - will give this a try. Always wanted something like this, but never could find the app by name/reference.

 

Follow this tutorial to fix android OS and android System drain ! Also get an extra 1-2 hours of screen on time using this method:

 

2 of thos

two of those apps won't work on Nougat because the lack of Xposed support

 

As soon as xposed support is present for android N, I will be sure to update this method. Stay tuned!

 

Just a follow up... before trying any tweaks and resets, you should check if your battery is healthy. If your battery is approaching 2 years, regardless of amount of use and cycles, it may just go bad and start discharging faster all of a sudden, without cause or reason.

I had previously posted methods of optimizing apps and doing data wipes, and these have indeed helped me to fix battery issues (and had worked well), but in the end, as my phone and battery had approached two + years, and the battery's capacity has decreased, and as well, began to discharge much faster (the rate of discharge) - with the combination of the two, less capacity and faster discharge means low battery life. At this point, it matters very little what tweaks you do in other areas of conserving battery for your phone.

Here's an app that i found that gauges the capacity and discharge rate well:

AccuBattery
https://play.google.com/store/apps/details?id=com.digibites.accubattery&hl=en

Using this i found out that my capacity had decreased over time to where it is now only 1600mAh of 3000mAh original capacity of the LG G3 battery. It also showed that even in deep sleep, the discharge rate was at 140mAh; this even with wifi off during sleep and using Greenify app to hibernate apps. That basically means the phone will drain 70% of charge overnight when not in use - pretty BAD.

Now, if you use this app and find that your battery capacity is near full, then you know that your drain problem is something other than the battery itself. This app will also show you apps that are using your juice. Hope this helps.