GSAM started bugging out last night, repeatedly force closing, so I just deleted it. Phone lost 16% in the overnight, but I think I found the culprit. The standard battery tool only showed one app running in the middle of the night and that it only used .1% of the battery. This is a digital car key and digging deeper it shows it in the background pretty much all the time, which makes sense. Looks like I'll need to either disable the key or turn off BT at night to save the juice. Hopefully that does the trick. Thanks for the tips, much appreciated!I think it's more likely just the GSAM bugging, but if you turn Bluetooth on and off again, and it's still high, then it might be that's the problem.
My uneducated guess is that smart switch is fine for some and not for others, I initially used it on this, then did a fresh reset (I find it quite cathartic to start from scratch!) And it definitely felt like it was lasting longer.
I think the issue you will have is it won't show anything beyond the kernel, but worth a try. There were a few other apps like betterbatterystats which could help dig deeper but don't know if they even work anymore.
The one thing I can see is your mobile signal looks pretty bad which would cause drain seeing as you don't have WiFi calling on - Might be worth giving that a go
But yea, try it again, then in the morning get
a) some more screenshots as well as from the Samsung default battery bit in settings
B) before taking GSAM ones, turn your Bluetooth on and off
C) have a look at your data usage, see if anything has been using your WiFi/mobile data in the background