[Droid Turbo 2 Q&A, Help & Troubleshooting] JWeller:
So. My phone has this problem, and its pretty weird (IMO). It is possible that it is a hardware problem.

I going to work and I dropped my phone. Didn't think much of it. The phone worked fine for several hours. It started around 40% and only declined somewhat, until about 2-3 hours later where it dropped rapidly to 6%. It was in my pocket when it dropped. I figured at the time that I had just forgotten to turn the screen off, so it drained much more battery. I then plugged it in, and it charged for a little while on a non-turbo charged cord, getting to 21% (which is what it said when it was off). After I turned it on however, it was only at 12%. I didn't bother with it at the moment, but after about 5 minutes it dropped to zero in about 5-10 seconds from when it started dropping. This was concerning, but I had to go back to work so I plugged it back in. When I came back and rebooted it showed 11%, and it stayed at 11% for several hours while I was using it, even though I wasn't charging it. Then randomly it dropped super quickly and died. I turbo charged it overnight. In the morning I booted it up and it immediately shut down claiming there was 0% battery life. It will not boot up without being plugged in. This goes on.

Usually, I charge it for a while and it will give a higher number than it will say when it boots up. It sticks at that boot up number for longer than it should, then dies rapidly. Occasionally it will boot up to be 0% and immediately die. I have tried turning in on and off again (without it dying) and it wont turn back on claiming too low of power regardless of how charged it said it was before. I have tried various charging cables and wall outlets. I have tried several battery repair apps, which did nothing. I was going to try and do a root version, since I figured that would be better but cannot root it. (Using adb to sideload comes up with an error (signature verification failed), trying to flash twrp fails (pre-flash validation failed) and normal root methods fail.) Oh yeah, and I've also factory reset it a few times.

So it seems to me that it's a software problem, namely the battery driver, since it appears to be charging and holding a charge for the most part, but then shutting down randomly due to the driver saying it is at 0% battery life. Alternatively, it could be a problem with the battery or charging port, although nothing seems to be wrong with the charging port visually.

Also potentially of note is that my normal turbo charger, when plugged in, puts a lightning bolt icon in the battery symbol, but on battery usage it says not charging. This could also be the chargers fault, since it had begun to fail previously (only working at certain angles) but it worked earlier the same day and now doesn't.

I didn't install any new updates to the OS or installed any new apps before this occurred either.

Any idea whats going on and how to fix it?

EDIT: I've been trying to look up and see if there was a driver or something for the battery that I could reinstall but I couldn't find anything. So, I ordered a replacement battery of Amazon. Now the question becomes will that fix my problem if I replace the battery?