Well , i had this problem since i bought my NDSL . it seems as if the battery runs out too quickly , my friend says he can run 10 hours on highest setting wich sounds pretty strange to me , as i run only 3 and half hours with earphones and a lot less without them . i took his battey and using a timer i cheked both mine and his battery's just to found out the problem is'nt the battery. they both run 3.5 hours . (with earphones , highest setting , using a R4 ) is the R4 more power consuming or is something wrong with my DS ? should i send it to repirs ? thanks !