Hi all,
Ok I have a old personal handheld fan and a couple of solar cells from a couple of sidewalk lights.
What I would like to do is build a solar charging circut to run the fan and charge the 2 1.2 Ni-cads to charge and run the fan. I'd like to have a diode in there so the batteries dont discharge, an led to show if the battery is fully charged and a switch to turn off the fan. On top of that im trying to just use resistors diodes n such from my junk drawer. I'm gunna use the whole thing on a food dehidrator. I made a scematic for it but would love anyones input!, thanks to all...

 

Hello,

Can you post your schematic?
That way we can see if things need to be changed.

Bertus

 

..a couple of solar cells from a couple of sidewalk lights

If you really mean "a couple", as in just 2, I don't think that will be enough power to move much air. If you know what your airflow needs to be, in say cfm, you can estimate how much power is needed to accomplish that. Maybe you already know the draw on the batteries while your fan is running?

Anyway, I think you'll need more square inches of panel.

 

Those sidewalk light panels produce almost no power.

Handheld fans use a DC motor usually requiring 2 AA cells, ie 3v at maybe 200mA.

The solar panels would be lucky to make 2% of the power required to run that fan. Unless they are much bigger panels than I am imagining?

 

Maybe his dehydrator just dries one grape at a time?