How long do these bishes last, providing that they don't have to CHARGE the battery all that much, I always make sure to start my car before I play too much music, but these things are so exspensive that I don't want it not to last for long. //content.invisioncic.com/y282845/emoticons/yumyum.gif.0556df42231b304b9c995aefd13928a8.gif