How I can fix my 3ds system power unit

¿I have a problem with my 3ds that if I don't use it for exactly for 1 day or to say 24hrs it those not work or turn on or charge even tho if is already fully charge and after this i have to wait 2 dy to a week before i can put it to charge again , but this problem got worse and now it been a week or so and now is not reacting to my method also i change the battery and i have the 3ds for 2 yrs only and took very good care of it please those anybody now?