My kids have FreeTime on their Fire HD 8's. They also have SD card storage. While at home on wifi, I download our movies, games, books... if I leave the Kindle on and charged, they can use all those things in the car and while traveling. If the battery dies or it gets turned off, nothing that has been downloaded can be played again until it connects back to wifwifi. This has been really frustrating as we travel frequently and bought these for this purpose what am I doing wrong?