Having an older car (12yrs), I have no USB sockets to charge/power the multiplicity of tech that I and the family carry on trips It seemed to me that the cheapest way to get a strip of 4 or so sockets in a convenient package was to look at USB hubs. I got one from ebay for £1.88 and looking inside the input power leads were directly connected to the 0v and 5v pins of all sockets which seemed ideal. The data leads all went through a chip under a blob of "sealing wax" but i did not care about that. However there was a problem, an Iphone would not take charge from simply the 0v and 5v pins. Digging onto other chargers I discovered that the two data lines were joined together (but to nothing else). A quick cut through the pcb tracks from the chip and a blob of solder on the back of each output socket has converter the hub to 4 way power distributor that works with all my devices. Fits quite nicely in the car too.
Disclaimer: This might be common knowledge but not to me nor did I find it through google searches hence posting it here hoping it might help someone else. Bob