There's no 12v version that I know of. To be honest, I don't know if 300W would run it but it might. We have a little pocket inverter (400W) that runs an Apple Express when we're out. We use that to Air Play to from phone, pad, whatever. That allows us to use Rhapsody, Spotify, iRadio or our own stuff. We also ditched the car stereo since broadcast stuff (except NPR) is so abysmal. Truthfully, we rarely play tunes when under way.