31 March 2006

My solar panel cellphone/pda charger

For a long time I was fascinated by the solar panels, and how they can, and most likely will, change the world.
When I'll have a house, I plan to get some big ass solar panels, and power the whole house with them. Unfortunately, for the time being I have to resort to smaller scale experiments, such as having 2 solar powered radios (moded them myself), a small solar panel RC car, and charging the batteries for my souround sound system with, surprise surprise, solar panels.

A while ago I got some 75 mA @6V solar panels, and last week I had some spare time so I glued them together with a plastic ruler (for support), then using some adhesive copper band I've connected their output together. There are 7 of them conencted together, so under optimal conditions I can get about 500 mA @5V (close circuit). This happens to be exactly the output of an USB port, when set to provide electricity to a device.

My new PocketPC Cellphone has an option to be charged from an USB port, so I've decided to make use of this feature.
I had a hybrid USB cable from an UPS, which at one end it had an USB connector, and at the other end it had a network kind of connector (UTP).
Since I had no use for that cable, I cut off the UTP end, and using some alligator clips (this is a prototype, I didn't want to solder it yet) I connected the USB cable to the solar panels.

The output was about 400 mA (didn't have the optimal illumination), but it was enough to charge my device if it was turned off. While it was on, the CPU+screen + WiFi was draining most of the power, so there was not enough to charge it.


Blogger VampiresWill said...

hope you dont run outta sunlight...otherwise you might have some trouble with power losses...good luck with that

1/4/06 12:24  
Blogger Radu said...

That's why the final design will have some rechargable NiMH batteries, to store some energy for the times there is no sunlight.

1/4/06 15:56  
Anonymous Anonymous said...

Using parrallel capacitors would help to fix this problem if you left it out in the sun all day

1/11/07 23:38  

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