[gearjunkeez]

Most car chargers provide a trickle charge... meaning, it will sloooowly charge your battery, but will prevent any drainage from standard usage. They will typically add charge if left plugged in for an extended period of time, so If you are just doing quick drives, you won;t notice any charge at all...

With that being said, there was a charger sold on ebay for the 6700 and also for treo 650. It plugged into the cigarette lighter and just had a usb port on it. You would then plug in your usb sync/charge cable and it would provide the same charge as being plugged in to your computer. I heard they were kinda dangerous and would void your warranty etc... but I never had a problem - I still have mine and use it all the time.

Do a search for "Rapid" car chargers as well - might help you out.