Instructables

Solar Battery Charger Cheap

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.
 
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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)

Step 2: Wiring

Picture of Wiring
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Take the positive wire from the solar panel and one end of the wire of the blocking diode and twist them together. Take the positive wire from the battery holder and twist it to the other end of the blocking diode. Do the same steps with the negative wires.

Step 3: Solder

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Solder the twisted wires and then put electric tape over the solder.

Step 4: Finishing Touches

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Make sure the rechargeable batteries are low on power so you can charge them. If you want you can put the charger in an altoids tin or a Tupperware. I'm not sure how much time it will take for you to charge the batteries. It will depend on how many mah your solar panel and batteries are. Enjoy
joshr1231 year 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) 1 year 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 B1 year 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
JCG5 (author) 1 year ago
(removed by author or community request)
MikB JCG51 year ago
Look at the diagram again, it's 8 cells at 0.5v EACH giving a rail voltage of about 3.2v (marked 3V2) ... and then a DC-DC converter to boost that further.
mikb they is 12 cells for a total voltage of 6v on the solar panel
and they is no dc boot converter just 4 aa to produce a voltage of 4.8 volt
unless you have linked to the wrong reply
@das: I was replying to the author (JCG5), which is why I linked to their posting, not yours.

http://www.talkingelectronics.com/projects/SolarCharger/SolarCharger.html

Try looking at the projects on the link that JCG5 was replying to (Phil B's link).

They are not a "0,5v cell which is very slow", and they are charging 12v batteries from that. It *is* a DC boost converter, as you can't charge a 12v battery from 3.2v. It's a modified "Joule Thief" design.
yeah i spent alot of time playing with joule thiefs i now use camera flash circuits i got so fed up of winding diferent transformers and toriods
they work on the same idea as a joule thief
i have looked into alot of this stuff befor and they are not always clear
i belive they have the 0.5 200ma panels in series for 4 volt
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
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