I love travelling. Most of the people love travelling like me. People love to travel but they also love their smartphones. When I travel, I love to read blogs, connecting over social network and sometimes, watch directions to my destination.

If you are like me, and I bet you are, if you love to explore new places in your car, you definitely need GPS so you don't get lost. But what if your smartphone's battery is dead and your car charger is broken? You are stranded at a place that you visited first time. You have no idea where to go and what to do or whom to ask?

We will help you make a Solar powered Smartphone Charger which can bring your dead smartphone battery back to life and also, you.

Gathering the materials :

Solar Panel (6V 20mA)
Solder (3")
Double Sided Tape (3")
Heat Shrink Tubing
Heat Gun
Zener diodes
Flux
Solder Iron
Wire Stripper
old cell phone charger



How to Do-It-Yourself :
  • Cut one end off of a USB extension cable.
  • Cut away the cable's outer insulation and isolate the power lines. These are the red wire (+5v), and black wire (Ground). Strip the ends.
  • The solar panel already has corresponding red (+) and black (-) wires.
  • Cut a 2-3" piece of 1/4" heatshrink tubing and slide it over the cut end of the USB cable.
  • Cut a similar piece of 1/8" tubing and slide it over either the red or the black wire coming from the solar cell. This tubing will insulate the wiring connections from each other.
  • Pick a rectifier diode from the pack; any one of them will do. Solder the diode between the red wires from the solar cell and the USB cable, with its cathode leg (that's the negative side, marked with the stripe) facing the USB side.
  • Solder the two black wires directly together.
  • Solder the smaller, red and black Zener diode across the two wire connections, with its black stripe facing the red wire side.
  • Slide the heat shrink tubing over the joints and shrink with a heat gun or lighter. (Hold the lighter flame over the tubing, rather than under, and move the tubing around to shrink all spots.) Always put the tubing on first, before you solder!
  • The rectifier diode eliminates incorrect polarity and prevents power from being drained from USB devices. The Zener diode protects them by preventing power surges over 5V (actually 5.1V).
  • To test your charger's output, place the solar panel in the sun and plug the cut-off end of the USB cable plug back into the other end. Use a multimeter to probe the voltage between the red and black wires.
  • Depending on how sunny a day it is, your multimeter should show something between 4V and 5V. The Zener should prevent anything from going too far above 5V.


Circuit Diagram for Charger :