Add Powered USB Ports to Your Car





Introduction: Add Powered USB Ports to Your Car


This will show you how to add powered USB ports to your car (yaris in this case) and wire one of them to power a phone from the dash to use it as a GPS in your windshield.

I am doing this in a yaris, but it applies to any car.

I will show you how to

1- Add a usb power supply that will be coming out from the dash to power my phone that I use as a GPS when it is attached to the windshield.

2- Add usb ports that can be use to charge directly any usb powered device from the two little unused rectangles under the parking break handle near the current 12v supply

For the circuit part of this (getting the power to the ports), please see my other ible here:

Step 1: Material

Step 2: Wiring the Car

I recommend an ethernet cable for this. The reasons are

  1. it has extra protection
  2. it is rigid enough to snake around tight spots, but soft enough to do very tight bends

Cut off the tip to make it easier to run, but cover the tip with hot glue so that it can't get hooked as you run it.

I did remove quite a bit of panelling, and it still took a bit of patience, and a good flashlight. I drew a red line on the pictures to shows approximately where I wired it. Long nose or needle-nose pliers can be useful for reaching.

Also, please make sure your car is off when you do this.

Step 3: Finding Where You Will Put Your Ports

I had spare "blank" caps in my care as I had a base model, so I chose to use these. I could have drilled directly, but decided to actually cast my own as you can see. You don't need to do this, but just showing that there are a lot of options. You can see my mold in blue.
Once that is done, you can secure your USB ports in place. If you are using header USB ports with long wires, you might even want to just have the wire come out as is, and keep it flexible.

Step 4: Connect Your USB Ports

You now have to connect your USB ports to your 5v power supply, whatever one that may be.

Step 5: Add Your Dash-USB Cable

Pick 2 wires from the inside the ethernet cable we ran earlier (once it has been cut at both ends with about 1-2 feet of slack). Remembrer what colour your pick, and add solder a USB port to the wire on the top end. On the bottom end, connect the pair of wires to your power supply.

To finish it all up, I tucked the usb port well into the dash and pulled the steering wheel up to clamp the port in place.




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    16 Discussions

    to author... does the 7805 give off any heat? If it does is it a small enough amount that I wouldn't need to include a heatsink?

    4 replies

    the one I used has alot of heat, the integrated heatsink is enough for it to work, but adding an extra one would not be a bad idea, it has been reported to help out, and just about any computer heatsink with a screw-hole will work. If you got for a slightly more expensive transistor (like 1-3$ more) you can get a much more efficient one that will give off almost no heat.

    The best heat sink in your car is all over, and that is the massive quantity of steel (steel doesn't have as high a heat transfer coefficient as the usual aluminum heat sink, but it has a very high specific heat, making it an excellent heat sink for tiny heat loads like these) in the center console, dash, and unibody.

    First, check (as in, with a multimeter) to make sure that whatever heat sink you have on your regulator doesn't have a voltage potential to your car's chassis (bare steel which you'll screw into). This should be tested when the regulator is in operation. In my experience, heat sinks are usually either attached to the package ground or they're insulated electrically from the board.

    Once you know it isn't going to cause an electrical short, simply attach the existing regulator heat sink to the car's chassis with something that conducts heat!

    Certainly, these TSR-12450 are much more efficent. However, like other highly efficient ones, they have a lower maximum amperage, so you should use a 1amp fast blowing fuse (this means 2 ports in use MAX and even that depends on your device). They are also much harder to find, I could only find them here for 10 euros each. A heatsink on L7805's is definitely a great very viable and safe option, but if you can get your hands on something like the ones I pointed to, then all the better for you! :) good luck!

    So, I'm planning to use the DROK 20A 100W High Current DC Buck Converter and I see that it's output is just under 5 volts and 20 amps. How do I lower the amperage, without dropping the voltage, so I do not fry my rechargable devices?

    1 reply

    The 20A is essentially the max the buck converter will output without frying when actively cooled (I would say that if it'ts not ventilated, run it at 30% of max if you can, no more than 50%). Whatever you plug into it will draw a certain amount of current, and that will be controlled by your devices. What you may want to do is put a fuse or breaker that caps the draw at whatever you feel comfortable. When calculating, I would say that phones usually have a max draw of 1.5-2A, and tablets can go 2-2.5. If you are making sure you plug no more than 10A draw in total, then those ballpark figures are more than enough. If you are going in higher amperage in total, make sure that the wire is thicker, especially if it starts getting longer than a few inches.

    Last think, make sure it's a switching converter, not like the one I used (which is fine for the lower amount of energy used at 5-15w)

    All wel and good but wat i want 2 kno is how 2 hotwire a car anybody kno? ( 4 scintific purposes of corse)

    3 replies

    All you do is heat a piece of wire over the cooker and touch the ignition with it, the trick is to run to the car before the wire cools down.

    For scientific purposes, telling you that essentially hot-wiring is crossing the wire from the battery's positive terminal to the ignition. But to REALLY hot-wire a car, you'd need a way to start all other essential systems, so fuel pump, oil pump, ECU in a modern car, etc. etc. and there is also the matter regarding the alarm system also that regarding actually getting INTO the car, good luck and take care in your "scintific" endeavors.

    i am currently working on an in-car tablet/gaming set up. I will be using this to play, charge, and connect external drives to my Nexus7 tablet. Thank you for the intstructable.

    just a thought on running wires, if you tape a piece of stiff wire to the end of your cable you can use that to push it through the fire wall of the car or into places that you cant reach. that way you don't need to run stiff cable.

    1 reply

    kind of like threading a needle; my next project does require that I go through the fire wall, but this one did not. The ethernet cable was nice because it is stiff enough to stay in place but soft enough that i could wiggle it around until it finally decided to pass where I wanted it to :p

    are you wiring this into your 12v line in parallel so you can still use your cigarette lighter for other devices? And how are you connecting this into your 12v line, are you splicing it in? Thanks!

    1 reply

    Yes it is in parallel with the 12v so the cigarette lighter still works. I made a macguiver plug to make a T splice where the cable clips into the 12v cigarette socket, but you can do it directly in the wire if you want. I did not include that because it was actually REALLY half-a**ed on my part.