Solar Cellphone Charger - Need some help

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saumaun

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Hey, its the noob again =]

Well, I have a few garden light solar panels here. Each one has it's own NiCad battery (1.2V, 600MAh)

My cellphone charges @ 5V.

From what I understand, I would need at least 5 solar panels to get 5V+ to charge the phone.
BUT this puts me at 6V. So, I'd need a linear regulator. I've already assembled the panels and tested to voltage, and all is well. But I need to know where I put the regulator!

There is the +5V Fixed-Voltage Regulator 7805 at radioshack, but I guess they need a minimum input voltage of 7.5V to put out 5V. Is that correct?

And assuming I can get 7.4V, I still need to know if this will work with the regulator...

Sorry if I left out any essential info. I appreciate your help!
 
Thanks transistance.

Now, I see there are 3 prongs to the regulator. The positive goes to the input, the negative goes to the common, but what does the output connect to? There's only one output.... where's the ground? The answer is probably right under my nose and I'm too stupid to see it =]

Thanks!
 
Thanks very much for the diagram!

Do you think if I take my project and this diagram to an electronics supply store that they would be able to tell me what parts I need?
 
saumaun said:
Thanks very much for the diagram!

Do you think if I take my project and this diagram to an electronics supply store that they would be able to tell me what parts I need?
Click to expand...

dought it most of the people at radioshack or other stores are normally really dumb about schematics and real electronics. it is really to do this just read more about regulators and stuff of that matter and you will be great
 
the parts are only

solar cells
LM 7805
some wire
perf board (optional)
the caps are optional but are good to have(you dont have to have the exact values)
 
davidbball13 said:
i made a picture to help you out
Click to expand...

Thank you very much for the picture! Now I get it. So I connect the ground wire from both the solar panels AND the phone to the common pin?


This is excellent. Once I get this all done, I'll post some pictures and maybe a video of it in action.

Again, thanks so much for your help!
 

Your missing one important specification and that is what the max current draw that the cell phone requires for charging the battery. Only then can you properly size the solar array you will need, at least 7.5 vdc (12vdc is more realistic as you rarely get full voltage out of cells unless under full bright sunlight) and a rated current capacity required by the cell phone charger circuit.

Lefty
 
I would suggest a low-drop regulator. It will give you more charging when the sunlight isn't so bright.

You probably don't need to worry too much if the current from the solar panel is lower than what the cellphone would normally charge at. The charging will be slower but the charging circuit will still cut off when the battery is still fully charged.
 


Ah, yes. I forgot to mention the output is 5.0V --.. 550mA.

The capacity of the batteries is 600mAh. Below the capacity, it says:
"Standard Charge: 60mA for 14 Hours."

@whiz115 - that is almost the same! The panel is identicle, but the circuitry is a bit different. Mine has the LED practically flush with the circuit board, and I also have a on the board. Each solar has it's own board.
 
saumaun said:
@whiz115 - that is almost the same! The panel is identicle,
Click to expand...

i knew it...
also the battery must be green and says "NI-MH 1,2V AA 600mAh"
small world huh? where are you from?!
 
Last edited:
whiz115 said:
i knew it...
also the battery must be green and says "NI-MH 1,2V AA 600mAh"
small world huh? where are you from?!
Click to expand...

My battery is yellow and black, and its a Ni-Cd AA600

I'm from Rockford, Illinois USA

This is one of my first successful DIY projects =]
 
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