Here is the power supply you need.
Small in size and can be used without the Carnetix powers supply and they output up to 3 amps.
I will be installing two of these in a small project box for a total of up to 6 amps output.
Then use two of these.
To hook them up take it to your local Radio Shack and buy the correct plug to fit in the power input hole. from that make you self a power wire.
Now you are all set and have 8 powered USB, that will power just about anything you could put on it.
Why not implement an LM (eg LM7805) based Voltage regulator to create a regulated 5v DC out (handfull of components) and use a regular 'Ritmo' style 7 port hub that takes an external 5v plugpack? Really not that tricky...
Its been a while but an LM7805 can pump out 3A quite comfortably. The fact that we have a flat full DC wave to begin with makes life even easier...
Check this out... I doubt this would cost more than $2 to make.
Fighting for peace is like screwing for virginity...
Consider 1A loading per port, each 7805 will dissipate around 7 Watts at 12V I/P. Multiply that by the number of ports and you easily have a furnace inside your car...lol. They need loads of heat sinking as well...In short, that is too much power wasted for nothing. IMO, you should be looking at nothing less than a switching regulator. Linear regulators like 7805 are so last century.
Another point to note is that most well engineered USB hubs control the 5V VBUS line on each port individually.They call it PPPC (Per Port Power Control) and has obvious advantages. So it is not just as simple as jacking up the amperage on each output.
Sure, they're inefficient, but they're cheap, easy to install, and they'll work. Just heat sink them. You're unlikely to be loading 1 amp per port, so that's a worst case situation.
A switching regulator is more elegant, of course, and if you just have to have one, mp3car sells a point of load regulator for about $35 from Opus or a similar one that you can add on to a Carnetix P1900 or 2140.
Another point to mention is switching OFF of the hub.
It needs to switch off with the PC and not with the car, otherwise the PC throws up USB errors as it is still running and the hub gets switched off by the car.
Not a problem at switch on as the PC starts later than the car and the hub has to wait for the PC.
MINI COOPER S PRO
HiJackX1 UAMCB w/ The Tobiathin Core Android/Win 7 hybrid system!
4x 10inch Tablet
1x Win 7 / Rear Entertainment PC
ft/ Web Server Streaming
And for that price i could do better with what i suggested in my earlier post.