If you want to make a DIY Apple Watch charger, you can with a little bit of work. Why there's no real way to make a DIY charger cable for your Apple Watch, you can make a charging box out of the charger you already have and a small box. You can use the box that the watch came in or another smaller box. You'll need to take a drill or knife to make a hole that will fit the Apple Watch and a line on the back to place the cable in, so it's not moving around.  You'll be able to feed the magnetic charging cable through the hole and then place the watch on the charger and plug it in. This way, you don't need to spend money on a charging box for your watch.