So I recently bought a new radio head to substitute my older one, everything went smooth and I could install it without problems. The new one has 2 USB ports, which I am going to pass-through to my cigarettes-lighter-dashboard to have a couple of "OEM-looking" USB ports.
I would like to have the possibility of plugging 2 music sources and/or charge them if they are mobile phones.

Now, since the radio head supports DAB+, I'd have to buy an adapter that would make use of one of those 2 USB, which means that in order to have 2 USB ports in my dashboard, I'd have to split one of the two USB provided by the radio head.

The power output could be not enough to power 2 phones at this point. I would still have the cigarettes-lighter power outlet, but I would like to avoid swapping plugs to an cig.lighter-to-USB adapter only to charge a phone.

Is there any way I can get 3 USB from the 2 provided by the radio head, without losing any power?

  • The power on both ports will be less then without splicing it. If this is or is not enough to power your phone(s) im not sure. If i were you i would pull another wire for the second USB port. – Granny Nov 13 '17 at 8:20
  • If the two usb from the radio cannot power what you need, then provide the power to those ports from a different source and just allow the data to be connected to the radio's 2 ports. From memory, the outer two connectors of the 4 are power, the inner 2 are data, but CHECK... – Solar Mike Nov 13 '17 at 8:55
  • @Granny I'm pretty sure that there won't be enough power, especially if on one phone I'd be using WiFi and bluetooth for example. Consider that I would want to use one of the radio's USB to plug a DAB+ module... – Noldor130884 Nov 13 '17 at 9:35
  • @SolarMike Do you know any device that powers up/amplifies a USB splicer, that can be connected to the cigarette lighter power socket? – Noldor130884 Nov 13 '17 at 9:37
  • e-bay does 4 way / 7 way usb expanders etc for computers which may or may not connect to mains power... I found one that is powered from the mains so will charge stuff without the computer connected : made by Kensington.. have a search - you may find one you can re-power from 12v... – Solar Mike Nov 13 '17 at 9:47

Anything that you do to split or boost the power on a USB line will most likely cause a phone to stop considering it a data channel. When it comes to the computer connectivity lines on USB, devices are much pickier than they are with the power lines. Also, you cannot have 2 different peripherals using the same data lines without using a hub (or similar circuit), and hubs (in many cases) aren't compatible with the source device (in this case your head unit) and/or the peripheral.

I would say that the best way to do this is one of these 2 options:

  1. Use the 2 USB lines provided by the head unit to connect as data channels, then add a 3rd that handles power only which is powered from your 12 VDC power (cigarette circuit is a good option).
  2. Install a 3-port face, and bury a hub like this in the dash. then connect 1 of the USB's from the head to your USB plate, and run the other to the hub. Then run 2 from the hub to the remaining plate slots.

Like I said above though, depending on the source and peripherals, a hub may not be accepted as a valid data line. Therefore your only true data line would be the one that goes straight from the head to the plate. Just like plugging your phone into a wall charger, it doesn't ask (with iphones) if you want to trust the device, because it doesn't consider it a data device.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.