ALL car adapters will not charge anymore because Apple does not support Firewire charging anymore. They will have to update to USB charging... as far as playing music, it works fine.
**If** the head unit uses a proprietary connection on their end of the iPod cable, it probably won't charge. But, many units today come with a USB connection instead, and there's every reason to expect that they will charge just fine.
Do you know why this is?
Apple's gotta draw the line someplace. It takes two sets of charging circuits (or one charge circuit, and one step-down circuit) to provide for both FireWire (12 volt) and USB (5 volt) charging. It's not necessarily about the money, but about the available space on the circuit board(s) inside the iPhone.

