[HTC Droid DNA] BigRed35m:
Here is my tutorial on how to make a USB charger that you can hard wire into the fuse box, or any power supply within your vehicle. No need to take up a perfectly good Aux Power plug, and something that can be hidden away under the dash or other methods of disguise.

If you don’t know how to solder (or electrical tape together if you have the intestinal fortitude to do it), then don’t bother trying this the way I did.

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This fabrication is simple to make, and cheap. Even if you don’t have the parts laying around like I did, the 5v regulator (If you buy one at RadioShack), is less than $5, the Fuse tap was $6 at Orileys Auto parts, and the USB Cable is $6 Anywhere online. Shop around; it’s not hard to find cheap stuff for this.

Supplies Picture

Specialized Supplies

5v Regulator

Fuse Tap

USB Cable

General Supplies:

All the equipment needed for soldering (solder gun, flux, solder)

Wire strippers

24 Gauge Wire

Multimeter

Shrink wrap

Step-By-Step

Step 1: Cut off the end of the fuse tap, strip the wire.

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Step 1a: Get approximately 1ft of wire, strip both ends and solder one end to the stripped wire on the fuse tap.

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Step 1b: Shrink wrap the exposed wire.

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Step 2: Take the other end of the wire attached to the fuse tap, and solder it to the Vin (Voltage Input) post on the 5v Regulator.

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Step 2a: Get approximately (2x) 1ft of wire, strip all the ends, twist the two wires together on one end, and solder to the GND (Ground) post of the Regulator.

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Step 2b: Get approximately 1ft of wire, strip both ends, solder one end to the Vout (Voltage Output)of the regulator.

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Step 2c: Slide shrink wrap around each of the posts (and wires attached to the post) and shrink it so the wires don’t short out.

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Step 3: Get your USB cord, cut off the Standard USB end. Strip away the protective coating and expose the four internal wires.

Step 3a: Strip all four wires, combine the green and white wires soldering them together and shrink tube them together.

Step 3b: Take the red wire, and solder it to the wire that is attached to the Vout post of the regulator. (Put shrink tube on it, but don’t shrink yet)

Step 3c: Take the black wire, and solder it to one of the wires that is attached to the GND Post of the regulator. (Put shrink tube on it, but don’t shrink yet)

Step 4: Take your fabrication out to your vehicle, locate something such as the fuse for the radio and pull it out, put the fuse into the fuse tap (match the second fuse with the same one the radio uses). Take the un-used ground wire, and attach it to a screw that is attached to bare metal (not paint, not plastic, but bare metal).

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Step 5: Take your multimeter, attach it to the exposed red and black wires of the USB cord and ensure you are getting 5v of Power and not 12 or anything else.

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Step 5a: If you do get 5v, shrink the tubing, hide your wiring, plug in your phone, and that’s all she wrote.

Finalized Picture

Shows AC Charge

Diagram of Wiring

It isn’t a requirement to tap into the fuse box, you can tap into any power line that supplies at least 5v of power (pretty much everything has 12v), and connect it directly to the Voltage Input of the Regulator, and it will work just the same. I just didn’t feel like possibly voiding a warranty on my car or anything like that.