Note: I have tested this only on an iPod Nano, but I would imagine that It would work for any iPod that charges via USB, or any device that charges over USB that uses a 5v source for charge.

The basic idea here is to charge my Nano via USB while in the car. The total project cost for me was Free-99. I had all the spare wiring and cables because I never throw anything electronic away. I did however build another one for a shade under $8 bucks. I mean thats not terrible for a car charger for your iPod and other USB chargeable devices. Plus its fun to DIY.

Typically, your USB port provides 5v of power through a single wire in a 4 pin USB cable. The normal operating voltage for most USB devices is between 4.75 V and 5.25 V. Ok great we understand that, but now how to get 5v from the 12 volt source (your car)? I stumbled upon this idea by accident, literally, I tripped over my wall charger for my Nextel-Motorola i870 and noticed that the adapter has an output of 5v to charge the phone. So, I went outside to my car to check the output voltage of my car charger, it was unmarked, so off to the Wal-Mart that is across the street I went to pick up a multi-tester. Upon testing the voltage output of my car charger I was astonished to see that sure enough the output was 5.15v well within the range to charge the iPod.

Read that last part again, I verified the voltage on a voltmeter. I also tested several other car adapters I had laying around, and the output voltages varied greatly, from 3v to 14v. So unless you are positive of the output voltage dont just splice away expect to get the right voltage to your iPod. (on a side note I also constructed a Firewire wire alternative from the aforementioned 14v car charger, and a tutorial for this one is coming soon). After verifying that the voltage was within normal USB operating range I used a USB extension cable to get a female USB plug. The next steps follow logically, splice USB female end to car adapter wires, seal, test voltage, go plug in. Direction and some pics follow.

Step 3: Step 1

Step 1: Verify that your chosen car adapter has an output voltage of 4.75v to 5.25v while plugged in. (USE Voltage Meter)

Step 4: Step 2

Step 2: Unplug and cut the piece that plugs into your phone off. Strip the wires to expose the red and black wires.

Step 5: Step 3

Step 3: Cut Female end of USB plug off of the USB extension cable, leaving about 8 inches or so to make room for error, and ease physical stress on your solder joints.

Step 6: Step 4

Step 4: Strip the USB cable so that all shielding is removed exposing only the 4 USB wires. We are only concerned with red and black so cut the green and white wires as close to the bottom of the area that you stripped, as possible

Step 7: Step 5

Prep wires with heat shrink tubing (I forgot the first time, only to remember after soldering everything together, and I had no E-Tape)

Step 8: Step 6

Solder red to red and black to black. Cover the joints so they dont short out, then heat shrink the whole thing to keep the joint protected.

Step 9: Step 7

Plug into cigarette lighter and verify voltage again. The pin-outs are located here ( just in case you are unsure. If everything checks out, plug your iPod in and charge away

Step 10: Follow Up

If you are comfortable with this type of set up, but would like to use a Firewire cable instead, use an adapter that has an output voltage of 12v to 30v. I have several adapters that output 14v constant, these are ideal to splice with a Firewire female wire. Coincidently, this cable ( would also allow you to mount the connector in the car (in dash, flush mount, console, or otherwise) and you can also hardwire if you wish.