Solar cell phone charger

osnarf

I'm planning on making a simple solar powered cell phone charger for a demonstration speech in my gen-ed speech class because it seemed like it would be fun at least. The best solar panel I could find for cheap has an output of 6v and 50 mA. My cell phone charger has an output of 5.0v and 700 mA.

Now my question is do I need to use a resistor to lower the voltage of the solar panel, and if I do I assume the output current will be even lower, and will it even cause the cell phone to say it is charging? I imagine it would take forever but as long as it says its charging thats good enough. I could probably afford another one and hook them up in parallel if you think that would help.

Also, out of curiosity, if you used 4 AA batteries in serial to get 6v, would you need to use a resistor to get it to 5v and, if you did, what would be the output current afterwards?

Thank you for your help!

mgb_phys

Using a resistor is tricky because it depends on the resistence of the phone charger circuit
You are probably OK feeding it 6V - but a fixed 5v output regualtor is very easy to use.

Blenton

Im sure you can find a better solar cell in an electronics store with at least 500 mA.

Topher925

50mA is really low. If you decide to use the one you're already looking at then just put a diode in series with it to drop the voltage down to about 5.6ish volts and it should work fine.

wyko97

sir can i see your circuit design...so that i have a reference about solar panel design cicuit for my thesis.

Evo

This is a 2 year old thread.

Here are tons of cheap solar cell phone chargers.

http://www.google.com/search?sourcei...+phone+charger