[Q] Car Dock USB connection... 12v, 5v or both?

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I am working on a plan to mount a vehicle dock in a more permanent and professional looking way compared to windshield suction cup with dangling wires.

In my previous thread I figured out how the mounting will be accomplished, now to sort out the wiring... Handling the audio connection is simple. The USB...not so much. I don't want to use a cigarette lighter to USB adapter if I can avoid it. I would far prefer to hardwire but I don't want to go hacking up the cable for no good reason. I know the USB standard calls for both 12v and 5v, if the dock is set to use 12v only, then it is simple, since my car has plenty of 12v power to spare

If it is 5v or both, then I am stuck needing a transformer, and in that case disassembling a cigarette lighter adapter and using the "guts" as my transformer will be my backup plan.

My dock won't be here till Thursday and I have no idea what pins on the micro USB to even try to test and see what voltage is fed to the dock.


Does anyone know the answer or have the ability to check?

Where did you see that USB can be 12V? USB is 5V. Are you thinking of SATA/PATA or ATX (which all have 5V and 12V) or Firewire (which doesn't have a fixed supply voltage)?

You'll need a transformer.

Laurent

You are right, I was thinking of the ATX power supply.


Ok, well at least I know what I am up against. Thanks

you'll need a transformer (require +5v), i did the same for my dock / car (hardwired power /audio cables). i ended up taking apart a cigarette car charger and connected it to a +12v and ground and everything works fine. i have the wire coming up from near the back of my dash area so no cable clutter up front at all.

Originally Posted by joeryu

you'll need a transformer (require +5v), i did the same for my dock / car (hardwired power /audio cables). i ended up taking apart a cigarette car charger and connected it to a +12v and ground and everything works fine. i have the wire coming up from near the back of my dash area so no cable clutter up front at all.

I did something similar, but I remounted a hidden cigarette lighter socket to a constant 12V source and grounded it twice for stability, so my phone and MP3 player can charge while I shut the car off and go inside a store for a second (don't leave it connected overnight though!). I ran the wires behind the dash, but I use one of my air vents that rotates all the way around as an able-to-be-completely-destroyed mounting location, then just cut a piece of wood to re-mount a new cell phone holder, etc.

For the Atrix dock, I pulled off all the suction cup mounting materials so it was just the threaded socket on the dock. I used a large enough drill bit to cut into the wood in the right spot for the threads to fit, and threaded them onto the wood to test. Removed it, sanded the wood down smooth on all edges, and applied texturized black spray paint to the wood to make it look like plastic instead of tacky looking wood. Mounted the car dock to it again after drying, and now the dock rotates with the unuseable air vent from portrait to landscape!

Hey, I've got a 2004 Acura RSX, it isn't a BMW.... works just great!

Originally Posted by GarciaM25

I did something similar, but I remounted a hidden cigarette lighter socket to a constant 12V source and grounded it twice for stability, so my phone and MP3 player can charge while I shut the car off and go inside a store for a second (don't leave it connected overnight though!). I ran the wires behind the dash, but I use one of my air vents that rotates all the way around as an able-to-be-completely-destroyed mounting location, then just cut a piece of wood to re-mount a new cell phone holder, etc.

For the Atrix dock, I pulled off all the suction cup mounting materials so it was just the threaded socket on the dock. I used a large enough drill bit to cut into the wood in the right spot for the threads to fit, and threaded them onto the wood to test. Removed it, sanded the wood down smooth on all edges, and applied texturized black spray paint to the wood to make it look like plastic instead of tacky looking wood. Mounted the car dock to it again after drying, and now the dock rotates with the unuseable air vent from portrait to landscape!

Hey, I've got a 2004 Acura RSX, it isn't a BMW.... works just great!

Nice! Have any pictures? I have a 2003 Mazda 6 and I have a EQ mounted in my top dash pocket so I was able to pull my +12v from there and grounded to my chassis. One question, do you get noise when you have your phone docked and charging while having the auxiliary/headphone port connected to your system? Im getting some slight interference that I can't seem to get rid off...

Originally Posted by joeryu

Nice! Have any pictures? I have a 2003 Mazda 6 and I have a EQ mounted in my top dash pocket so I was able to pull my +12v from there and grounded to my chassis. One question, do you get noise when you have your phone docked and charging while having the auxiliary/headphone port connected to your system? Im getting some slight interference that I can't seem to get rid off...

I'll take some, one day...! I don't use the headphone port really, I have an aux input on my aftermarket headunit that I connect my ZuneHD to, so no use for internet radio or downloading music to my phone, EVER.... with my aux input, I always manage to get engine noise, no matter how I position the wires and how strong I ground the charging devices behind the dash.... Looks clean as hell though, just sucks about the slight engine noise! Sorry I can't help

My Mazda RX-8 is getting feedback as well. I need to try another MP3 device to see if it when connected to the power and aux it gets the same feedback.

If it does (different devices) then it's an issue with the grounding on the lighter or a diode on the alternator.

I am considering getting a car dock but have a question; do you have to plug in and remove the 3.5mm audio cable every time or does sound go through the mini usb with a permanent 3.5mm going out the back of the dock? can't find enough info. the motorola site explains nothing; click here.

Originally Posted by psymont

I am considering getting a car dock but have a question; do you have to plug in and remove the 3.5mm audio cable every time or does sound go through the mini usb with a permanent 3.5mm going out the back of the dock? can't find enough info. the motorola site explains nothing; click here.

It goes through the MicroUSB - you have to use the supplied USB cable because at the end of it, on the USB-A side, there is a split attachment for the 3.5mm jack that you can hide behind the dash easily and connect to the back (or front, if applicable) of the radio