Augusto Yipmantin wrote:

>Dear Olin,
>
>Excuse me please for use [OT] instead [EE].
>And thank you for your question.
>This solar panel is a little bit expensive, yes! You are right, but it
>is what I receive to do the job.
>Maybe a $1.50 inductor will be part of the solution for my project, but
>in my country is not possible to get the adequate inductors as new
>parts. The only one way that I have to start this project will be
>testing many 2nd. hand or used pieces until I find the adequate unit. 
>And as I am a beginner in this field, may you tell me how can I ask the
>group to avoid being silly?
>
>Augusto
>
>  
>
You can wind your own inductor and measure the inductance with a 
function generator and oscilloscope (if you don't have an L meter)
You can usually get a suitable filtering core from a computer power 
supply. The yellow ones are for filtering.

Your voltage requirements indicate that you could almost use the 
transformer from a PC power supply. If you lower the switching frequency 
a few kHz you could achieve an input voltage in your range and get the 
voltage out that you need. This is quite a hack to get working though.

One comment. You measure current in 'A' = Amps, not 'Ah' = Amp*hours
HTH
--
Martin K
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