hi!
I want to make a mobile charger using solar energy.
please tell me how to implement it. The size should not exceed
(15cmX6cm).It should be portable also.I am a new comer. My knowledge
is very limited about it.[/i][/b]

 

someone is having a somewhat similar problem in the projects section, 'need assistance' is the title of the thread.
have you tried googling things up? i guess you'll need solar panels, rechargeable batteries, an AC to DC converter, a reasonable step down circuit.

__________________
Everybody can but not everybody will.

 

you are going to have trouble finding solar cells in that dimention to provide the voltage required to charge a cell phone battery , 3.6V ??
aside from that, when you find some that exceed your cell voltage
just hook them up to your cell phone battery , in the proper charge charge mode ( + to + and minus to minus ) and you are good to go..

 

You mention solar panels, rechargeable batteries AND an AC to DC converter in the same context.
Why an AC to DC converter? There is no AC involved in that process.
Or did you mean a DC to DC converter, :wink: to step up the voltage? If so, it only complicates the project and introduces more losses. Remember, the original question was about a VERY small solar panel with a rather limited output.
The most efficient way would be to find out what voltage is expected at the charge input socket of the mobile phone and then find a solar panel with a matching or slightly higher voltage.

Klaus

 

have a look at this http://www.maxim-ic.com/appnotes.cfm/appnote_number/484 page, im not sure if the circuit would work to charge litium batteries (maybe someone else could shed some light?) but its certainly an efficient charger