Q: Can I put the Apple Universal Dock in my car, and then run a cigarette lighter-to-Dock Connector to the back of the dock to charge my iPod? Then I could use the line-out for my stereo. I have been told it won’t power it, but isn’t the Universal Dock simply a dock pass-through?
A: The short answer is that this should work just fine.
Generally, connecting just about any charging accessory to the iPod via the Universal Dock will pass power through to the iPod with no issues, in the same way that the iPod charges when connected to your computer via the Universal Dock.
The only caution is to be careful about lower-end accessories and older iPod accessories.
Many of the cheaper accessories don’t provide enough power, or don’t provide it using the proper pins, and this can cause incompatibilities when passing through the Universal Dock. These problems are relatively rare, but with the wide variety of lower-end iPod charging accessories available, it’s difficult to say with any certainty that every possible accessory will work without issue.