Ok, first let me setup the current situation. I have a DSTWO with a 16 GB microSD card, all in a DSi XL that also has a 2GB SD card (if that is of any difference). I am also a huge fan of the original Digimon series. Original meaning adventure 01 and 02..... everything after that does not interest me at all.... So in my small apartment it is pretty dark usually, which i don't mind so much. Anyway So I have my DS on the lowest screen brightness (which is plenty bright in this room) and I have been watching Digimon episodes one after another from adventure 01. All of this is from Moonshell. Each episode is about 20 mins long, and so far I am at episode 31. All off the battery. So that means from a full charge my DSi XL has been going for 31x20mins= 620mins....which is 10 and 1/3 hours I'm impressed. And if you are wondering; yes I have been watching my DS for 10 hours straight.....so what?