I have a n3dsxl that I've had for at least 2 years, and it seems like the battery doesn't last as long. It seems to last about 3 hours now, not sure if some games drain the battery more than others but been playing Jewel quest and I can't see how that game would be a battery hog. Usually I'd let it run down to 50% before then recharge it, does that have something to do with it