I needed more than 500mA charging current in the car for the Note and its big screen (with GPS going also). I knew that I needed to short the D+ and D- pins of the USB charger or cord to let me pull more than 500mA off a 1A+ car charger. I chose to modify the chargers so I could use any standard cable for charging. I did this to two chargers.
1. Belkin Dual USB Car Charger http://www.amazon.com/Belkin-Dual-US.../dp/B001ILBNGA
2. Griffin PowerJolt Dual Micro Universal Charger http://www.walmart.com/ip/Griffin-Po...142050&veh=cse
I modified the Belkin first. I used an Ohm meter to confirm I was shorting D+ and D- on the “fast charge” port. Once I put it back together, I confirmed I had 5V across the outer pins and the inner pins were tied together. When I plugged my Note into it using a standard cable, I got a MTP message and the USB symbol appeared in the top left corner. It thought I was connecting to a computer. Removing the cable sent the Note into a media scan.
So I took it apart and double checked. I noticed that the shorted data pins on the high current USB port were about 2.5V and the low current USB port data pins were about 2.0V. I also noticed that the 5V pins for both ports were connected together on the PCB (meaning they are fed off the same 5V regulator). I then shorted the data pins together on the low current port and it worked with that port! The Current Widget showed about 1A and no MTP message. This pointed to the data pins needing a specific voltage (or range of voltage) to make the note charge at 1A (2.5V on the data pins didn't work, but 2V did).
Next I moved onto the Griffin PowerJolt dual charger. This is my favorite car charger as it is very low profile. I did the mod to one of the ports and got the same MTP message (along with only 500mA charging). I noticed the data pins were at 2.5V and that two resistors making up a voltage divider for the data pins were right there. I changed the divider ratio (adding a 50K Ohm resistor in parallel with the resistor that went to ground). I re-measured and saw 1.94V on the data pins (very close to the 2V on the working Belkin port). I plugged her in and sure enough it worked (AC charging and about 1A).
Depending on your charger, it seems as though simply shorting D+ to D- may not be enough to get full current. The data pins have to have the correct voltage on them. Around 2V works although it may be a wide range of voltages (maybe 0V up to 2V?).
Later I went back and modified the high current Belkin port so its data pins were about 2V. That port then worked well too.