what you guys don't realise is that stamina battery report is evaluated and changes as you use the phone, what it's telling you is that if you continue to use the phone like you're doing since last full rechatge then your battery will last xxx amount of time - it's quite cleaver actually
An example - if you are using your phone for a day for say just making calls and texting etc then the time reportd say 48hours will reflect that usage profile/pattern until it changes, so if during that day you decided to use a game that was very demanding on the battery or even watch a video - the extimated battery time will change dramtically in response to your usage pattern, and for information - I have a game that is so demanding on the phone that it will run the battery down even with the mains charger plugged in - so for some applications like demanding games even the charger cannot keep up with the power demand required by the GPU and CPU - that is how it is
I'm not saying stamina mode doesn't have issues but you need to consider what I've written above - also stopping the app and clearing the cache will reset the usage profile so you're fixing nothing just reseting the stats
