I ended up switching to a 20k mah battery pack. That thing lasts forever. In fact I have played for a few hours and it's still almost fully charged.
One problem I noticed after the original post: When you are gaming if you try to do a save state or load state.. opening the menu can sometimes cause a brownout loop where it keeps flashing the screen. When that happens if you can click on the save or load state between flashes then it will go back to the game and resume as normal.