So this started with me last night.
Got stuck at 1% and tried to kill the battery with hi-res games and it wouldn't die after 10 min.
Took my otter box off and put it under a blanket and went to bed and it charged to 60%.
Called T-Mobile and they said it was actually a Samsung software problem, and we're basically SOL until Samsung actually fixes it. Said if it completely dies they will replace it but it's probably just gonna happen again. He recommended factory reset as it has helped for others.
Phone gets down to 4% on the charger for about 15 min. I take it off charger, take the SD and Sim card out and let it sit for 20 min.
Turned it on and im at 27% now…
I have come to 2 conclusions: Samsung is robbing us and seem to not have any plans to fix it, and that the phone is actually charging while the battery logo is flashing, the phone just doesn't recognize it until you restart it. I'm about to see after another 15 min and update.
Edit: charged for 15 more min. Restarted. Stayed at 27% for about a minute, and since typing this edit, I have dropped to 10%