Volumio stops after 1 song


i have built a portable music box. It works with a 12V car battery. My RaspberryPi 3+ is powered via a StrompiV2 (HAT), which has a built in wide range voltage input (6V-61V).
If i run the system in my house with a 12V power adapter everything works fine. If i boot the Pi in my music box i can start a song, then i get this loading circle animation. After a few seconds the song is still running but my display shows it’s at 00:00. After the song was played completely Volumio doesn’t play the next song in the queue. :neutral_face:

Anny suggestions?
Do you need more information?

Thanks :slight_smile: