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Picture of Solar Battery Charger Cheap
This is quick and easy to make. I have a portable USB charger that is run by batteries. Sometimes I charge my phone while I'm at school because battery is low. The batteries last for about 15 hours of charging. The big idea is that I wanted to not use so many batteries and then throwing them away. Then i started using rechargeable ones and made the solar battery charger.

Step 1: Purchase Materials

Picture of Purchase Materials
Materials: 6v solar panel (RadioShack) 2 Blocking diodes (Amazon) AA battery holder (Amazon) 2 AA rechargeable batteries (Amazon Tools: Electrical tape (Home Depot) Soldering iron (Amazon) Solder (Local Hardware Store, Amazon)
 
joshr1232 years ago
I stabbed the top with a pocket knife and fed the cord through, makes it look better
Most small solar cells have a built in diode, and with care that is all that would be required.

However, it would be wise to include some kind of charge protection to avoid ruining the batteries by over charging,
JCG5 (author) 2 years ago
What's the main concept of the "joule thief"?
it takes the last joules of power out of a battery that most devices can not do you can run an led on a joule thief for weeks when the battery wont work in any other device
and when that one is run down you use two and so on till they is nothing left at all in the batterys
Phil B2 years ago
Apparently, solar chargers are more complicated than I imagined if they are to be effective. I saw your Instructable and went looking for some schematics. Three solar cell plans can be found here. Some good explanations of problems involved in a working solar cell schematic can be found there, too. (I have no relation to Talking Electronics, but I am interested in an inexpensive way to keep my iPhone working, especially on a long flight.)
thats just an over complercated idea all that is really needed is a solar panel a diode and a battery now if you dont wont a charge controller you wont a solar panels that charges at below the the 0.1c rating so say you have a 1.2v 2500mah battery the max output of your panel you would wont is 2v at 125 to 250ma for trickle charging
you only need 1 diode otherwise your wasting power well the solar panel wont start charging till it is 1.4 volt over the bettery foltage to get past the forwed voltage drop of the diodes