If the plug pin is always positive, all you need is resistors. Diodes will result in a forward drop of half a volt, which may severely screw up the charging efficiency.
I can't find the youtube instructional video I looked at before authoring my Post #24 in this thread, but in addition to its "producer" (surely, also its "director" and on-air "talent") using a breadboard for the junction, it did mention that the data wires on the load side need to be shorted, so that the phone will sense that it is connected to a dedicated charger and attempt to draw more current.
I remember when dedicated, switching power supplies first became readily available in the early 1980s, and we had a bunch of 3 amp ones but our bootleg Zaxxon circuit boards drew closer to 5 amps, we tried just tying the two 5 volt outputs together, but the problem was, the output voltage sensing could detect in inaccuracy if even a few hundredths of a volt, and so the one that saw its voltage as being too high would attempt to lower its output voltage, which made the other try to increase iits voltage, and in no time, one of them would heat up like a toaster before tripping its overcurrent circuit if it had one, or blowing its fuse.
I bought a few of the ultra-cheap 110 volt AV plug-to-cigarette-lighter socket on eBay for a dollar or so each, but was disappointed to see that they only source .500 amps and then shut down. I would expect the circuitry in a similar, Hong Kong "free shipping-if-you-don't care-when-you-get-it" 110v to USB adapters use the same regulator, but from what I have read, any old USB port is capable of outputting 1 amp, so the simple, single jack.plug with the shorted data pins ON THE LOAD END does enable the load device to draw close to one amp, thereby cutting its charge time in half.
FWIW, I didn't find any premium charging cables touting higher gauge wire, whereas premium, long HDMI cables to use larger wire for its current sourcing circuit.
Edited by AntAltMike, 19 February 2014 - 07:33 AM.