I have never known anyone to run them in a car or truck. You would probably want to plug them in to charge when they are not in use, which would become a huge pain in the [censored] for me.
These are the wireless bluetooth speakers I use. Unlike most of the others you can run two of these at the same time, for stereo.
Good luck.


Curt Warren
Salt Lake City
1948 1.5ton Loadmaster
http://photobucket.com/48loadmaster