DIY Old Phone Chargers into 6V LED Lights

If you have an old phone charger lying around and don't know what to do with it, this article might give you some ideas.

You can actually modify a phone charger to output 6V and turn it into something useful. If that sounds interesting, keep reading. You'll need to find some LED boards—you can tweak a light setup or do some soldering to make it work.

With two 6V strings, you can cut them and connect them in parallel as 3V, and then you can finally put that old phone charger to good use.

As shown in the picture above, this is a 5V 500mA charger. It comes with an optocoupler, which makes it easier to modify.

The image below shows how it looks after modification—you can use it as a reference.

The voltage regulator and this resistor set the voltage division for the optocoupler feedback. If you want to increase the voltage by 1V, you can simply add a 1N4007 diode in series before the regulator, which will drop about 0.7V.

The voltage comes out just right.

This setup can handle a 5V fan. When it first starts, the voltage will dip to around 4.8V, which is fine if you just want to power a small LED.
Later, you can make your own matching light setup.

Done.