There are many DIY guides to make a solar USB charger.
This is a very short guide to make a solar USB charger with altoids case.
It took me about 20 minutes to construct everything. Very Easy to make.
Parts you need:
USB charging Circuit
Solar Panel 4V or greater
AA battery holder
AA rechargeable batteries
Altoid case (any kinds works)
Tools you need:
Glue gun or super glue
I made my own circuit. But you can buy a premade circuit from online market places, minty boost kit, and other sellers. Normally, they cost around $10-$15. Choose one that works with kindles, iPhones, iPods, GPS, etc.
You also can use a cheap USP charger. Some of them do not work with Apple products.
Do not try and make a 6V or 9V circuit.
If you are going to use two rechargeable AA batteries that put out total 2.4Vs, you need a solar panel that is at least 3-4V just to meet basic levels of charging. The higher the voltage of your solar cell the less light you need to charge up your batteries.
A bigger and better solar cell would give you more power, but it will not fit into the altoids case. so if you have a bigger case and cooler looking case, then please feel free to use bigger solar cells.
It is safe to connect 1N914 diode directly to the posivie solar tab on the solar cell. When soldering make sure the black bar on the 1N914 diode is point away from the solar cell. The black bar is the negative side and prevents power backflow. if you connect this wrong, then the power is going to flow into your circuit.
Solder the diode’s positive side to the positive solder point on the solar cell. solder a wire to the other end of the diode. solder a wire to the negative solder point on the solar cell.
I taped it up for more protection. but you do not have to.
Let’s connect the solar wires to the battery pack wires. Just connect positive to positive and negative to negative. it is easy.
if you bought a charging circuit from online marketplace, then you need to find + and – spot on the circuit. if there is a switch, then be careful when you use it.
Now, all you need to do is solder the positive bundle to the positive on the circuit, and the negative bundle to the negative on the circuit.
It is completed. you can test it now.
Before you glue your circuit to the altoids case, try to place everything in the case and see how you are going to place all the parts together. Since the case is conductor, I put some electrical tape below my circuit board. Just in case.
Cut a hole so that you can use the USB port.
Now, I used glue gun or super glue and placed the part.
Can you close the lid? if you can, then you are done.
Go charge your batteries and enjoy.
When I made this, I did not take pictures step by step but when I make it again, I will update these steps with detail pictures. I gave this one to my professor. When he saw it, he asked for it.
Don’t give it to anyone.