solar powered fan

I have old solar garden lights, which do not work well anyway. They were used to charge two AA batteries. I want to re-purpose the solar cells to power an old computer fan or two. The fans will go in a vent in my garage roof. I just want to have the fan turned on when the sun is shining.

Any advice to give me? Is this a good idea? What to watch out for? How to proceed. etc...

Sorry if this not the right forum for this.

While the idea is workable, I don't think it will work as well as you imagine, mainly because computer fans just don't move enough air (certainly not enough to cool a garage space, which is what I imagine you are trying to do?); larger fans (say, perhaps a 12VDC automobile radiator fan) would work better, but would of course require a larger array (mainly for the current needed to run such a fan at a useful speed). In order to know how many cells you would need, you would want to measure the current capability of a single cell, plus its voltage output, in full sunlight at noon-time.

cr0sh,

I agree that it will NOT move very much air, but this was attempt at re-using stuff that I will probably just through away.

It turns out the old computer fan is also 12 VDC, so it would take a bunch of small solar cells. Also, it is not a simple electric circuit. The fan has three wires, red, black and yellow. I would not figure out how to get it to run.

First as to the Red, Black & Yellow (sometimes white) the yellow or white is just the tachometer output from the fan. Not a concern. The red is + and the black is - as to running the fan.

The problem is that a typical computer fan in the 80mm and 120mm sizes typically draw about 160 to 200 mA give or take. Therefore you want about 12 volts at 200 mA at least to run a single fan. At two fans the current is up to 400 mA.

That becomes a good chunk of current from a few solar cells that powered or charged batteries that delivered maybe 10 mA. That being the problem. You would need a considerable number of those solar cells to make this work.

Ron

Solar garden lights were made as cheap as possible in a country that is know to make junk that does not last long.
The solar cells probably don't work properly anymore like most of mine.
Also the surface of my solar cells has been destroyed by sunlight.

20 of the solar panels in series-parallel will probably run a computer fan at noon when the sun is shining.

Audio guru you are right. That panel shuld be ded by now. Too ship to last that long