I've had my 3DS since release date, so natural the battery is nearing the end of its life, and in need of replacing. I began noticing the battery was losing its charge, even when the 3DS was switch off. For example, I would turn it off at night with 50% battery, and wake up to find it was dead. I brought myself a new battery, but this behavior is continuing. The battery can't be at fault, because if I leave the 3DS on, it was will last about 6/7 hours of gameplay. Its just when the 3DS is switched off, I still lose power. It drains the battery to the point where it loses the time and date settings and the battery is dry. Has anyone else had this problem? or know what the cause maybe? My 3DS is out of warranty now, so I'd rather avoid sending it to Nintendo for repair. Only other thing maybe worth noting is I have used a DSTwo on my 3DS at times, and I know that drains more power. But I havn't used my DSTwo in the last month, and this still happens!