I was wondering if anyone has tried one of these in an attempt to charge the 3GS off of a 700bt. I would assume you could plug the charge USB lead to a 12v to 5v adapter, and put the other one inline between the head unit cable and the ipod cable.

http://www.shopaddonics.com/itemdesc.asp?ic=AA2USBPC

The ipod cable won't work with the extension in place.

As far as I know the F series supports 3GS charging. Where did you purchase and what cable are using?

I've been using the Pioneer CD-IU230V cable, and recently switched to an Apple Composite AV cable. Neither charge reliably. The phone will report that it's charging about once in every ten connects. All the other times, the iPhone reports that it isn't charging, but the battery level indicator doesn't get lower, and it doesn't rise either.

If you connect and disconnect you iPhone a lot it can where out the dock connector. This may be your problem.

well, I have to report that using the cable I linked above, along with the Apple AV cable and the extra power end plugged into a 12v to 5v cigarette adapter, it does reliably charge my 3GS and does not interfere with the 700bt seeing or controlling the iPhone, and presumably any other iPod that would get plugged into it.

I also tested it with my Pioneer cable, and it charges and operates just fine too.

Now to tuck all that extra wiring back into the dash.