I've made a custom USB cable to be able to charge my PS4 controller through the EXT port in front. This is very useful as many controllers tend to get their normal charging port in the back broken after long use.

Supplies

There are not many supplies needed as this hack is quite simple. You will need:

2 USB cables (you need only the USB part that goes into your charger on both cables)
Cutter
Pliers
Small flat screwdriver (I used a swiss knife)
Soldering Iron
Some thermoretractable tube

Step 1: Cables & Pins

Cut the ends of each cable. We only need the USB that goes into your charger. One of the cables will go into the charger and I will leave the socket as it is. The second socket will need some adjustment. As seen in the image I found the pinout for the EXT port and on the lower part the exterior pins are the charging pins. 5V pin (pin 12 - lower left) and GND pin (pin 6 lower right). I removed the exterior metal shell of the USB using the swiss knife to free it a bit and then with the pliers (see the video for more detailed process).

Step 2: Custom Socket

After removing the shell, I revealed the 4 USB pins. We will only keep 2 of them (pins one and three will be removed). To remove the pins I used the swiss knife.

I gave the shape of the socket by carving into the plastic with a cutter and a file (can be done without a file though) until it fitted the EXT port on my DS4 controller.

Step 3: Wiring

USB cables have standard color wires: Black - GND / Green - Data + / White - Data - / Red - 5V+.

We will keep the RED and BLACK from the USB cable and the GREEN and RED from the custom cable (EXT).

We will connect the GREEN (EXT) with RED (USB) and the RED (EXT) with BLACK (USB).

Solder the wires together (don't forget the thermic tubes for insolation), isolate them and you are done.

Step 4: Plugging in to Remote

If all is well you can now charge your controller through the EXT PORT.

DISCLAIMER: Be careful how you insert the plug into the EXT port! It should go with the pins facing the ground so it connects with the bottom pins from the controller. Inserting the PLUG incorrectly might damage your controller.

Enjoy!!!