This is the Car Plug Splitter from CDRKing. The usb charger on the right was bought separately.
Right away there are problems. The stock lighter that comes with my car only fits in one of the holes, is loose, and it doesnt work. Its brand new, still in warranty, but I could not resist the urge to hack it.
Here's what it looks like inside.
Right away I see a safety problem. There is a hole in the front and I see a piece of stiff wire covered by shrink tubing. However the tip is exposed and is very near a metal part where it could short.
Upon opening the tube I see a resistor.
So it looks like there used to be a LED light in the hole. Well, I cant leave this fixed so I bent the end of the resistor and covered it with shrink tubing.
Here you see why the cigarette lighter doesnt work. There is a several mm gap (red arrow) so it doesnt make contact.
The solution is simple. I need to make electrical contact with the central post of the lighter
I solder on a spiral of stiff copper wire. To make the solder stick, I had to abrade the metal (probably iron) with sandpaper.
To make the lighter less loose, I merely smeared some solder on the inside
UPDATE: unfortunately the lighter still isnt working. I think the wire moved a little to the side and doesnt make contact with the central post. more testing needed. To be continued