Rechargeable Flashlight for your Car

Step 2 Making the LED array

The first step is to figure out how to arrange the LEDs. Since my power source is a Li-Poly battery which gives out 3.7V I could not arrange the LEDs in series. So I used parallel. To correctly use LEDs you must use a resistor on the negative leg of the LED (this is the short leg or the side of the LED with a cut to it). In parallel you should also use a resistor per LED and in my case that means 3 resistors. To make it easy to solder the resistor and LED together I hooked them together as seen in the first picture. I then soldered, and snipped away the excess material. Once I had done this for all 3 of my LEDS I soldered them together. I started with the positive legs and soldered together as seen in picture 2 below. I did a similar thing with the negative legs (now with resistors) as seen in picture 3 below. Picture 4 below shows a switch wired to the positive legs, and finally all attached to a power connector for the board.