iPod / iPhone Dock with Full Time Power

Prindle19 · 07-20-2008, 02:08 PM

Hi,

I'd like to add my iPhone 3G into my carputer, and have a few questions on the best way forward.

Here are my interests for this project:

1. Need to have USB 2.0 connection to carputer

2. Needs to charge iPhone while car / carputer is powered off.

(I frequently have to leave my phone in the car - want it to stay powered during the day to charge.)

This was possible with my Windows Mobile phone - it had a dock that had 2 USB mini connections - one for data and one for dedicated power.

So here's my question.

How do I do that for the iPhone.

Should I (Can I) simply hack a cable that will connect the data side of the USB to the carputer, while drawing power from a full-time 12v source in the car?

I believe that the iPod / iPhone can take 12v power from the Firewire connection.

I don't know however if you can mix and match connections (i.e. Data from USB 2.0, power from Firewire)

If I am required to only use one connection mode, USB 2.0, can I simply step down the 12v from the always-on 12v rail from the car to 5v, and essentially supply a constant 5V connection to the dock while only providing a data connection while the carputer is turned on?

Thanks!

adventurer2370 · 09-20-2008, 03:07 PM

I think you will find the iPhone 3G dropped the firewire (12v) charging option (many unhappy people with docks that don't charge anymore)
You could make a custom cable that provides 5V from a constant source and the data pairs split to another USB for connection to the carputer.
Modifying an existing cable shouldn't be too bad or buy the dock connector and make your own.