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help making solar charger please read?

i want to do many things in life, one of them being able to harness the sun..., anyways, hi all, im interested in making an iphone charger such as this one https://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/ now i dont really want to spend much money on this (he says i need about 70 bucks) i have about for good panels that say i should get 2v at 20amps but i get more than 2v, i have 2 diodes i got from radioshack so i think im covered there, any ideas or thoughts on how to do this would be great, also i want to learn the formula for calculating what ratio of amps and volts i need to charge a battery thanks all

nfarrow7 years ago
appolo7 years ago
The output voltage of a solar cell will always be higher without a load connected. If I understand you have four cells at 2 volts each. Look at your solar cell as a DC battery, it has a positive connection and a negative connection. The cells can be connected in several ways to either increase voltage (series connection) or connected together to increase the available current (parallel connection) Lets say you require 4 volts... you can connect 2 cells in series, + on one cell connects to minus or negative of the other (similar to two batteries in a torch one on top of the other) Now you can do the same with your other two cells to make 4 volts. By combining these two stacks together in parallel (connecting both + ends together and both - ends together, you still have 4 volts but now you have doubled the output current! I hope this helps. There are a number of internet sites you can visit for more info on solar panels and chargers etc. Regards You can connect the cells in a combination of series / parallel to achieve the correct input voltage for your charger.
tylak (author)  appolo7 years ago
yes i already knew that, *edit: i have 4 panels not for* what i need is the formula, and also cheap cheap parts that i can use for it, thanks anyways appolo