1. Jul 12, 2008

### marzelvane

Hi Eureka

I'd like to make a solar powered fan, but don't know how to convert the power from a solar panel to the fan. Perhaps I don't have to do anything, I can just hook it up?

Requirement: If the sun is out the fan should be running. At night time the fan should not run. In other words, I'd prefer to not use batteries.

Here are the current specs:

I bought a small desk fan:
http://www.acehardware.com/product/index.jsp?productId=2254749

There is a small plastic housing (about 1inch by 1inch) that has four wires attached (looks like 2 going in and 2 going out). On this housing it says:

6A 120 VAC
3A 240 VAC

I have not purchased a solar panel yet. What type of solar panel do I need to power this thing (i.e. power rating, voltage, amps, etc). It seems to me like 6A is a lot....

In my head I picture: mounting a solar panel outside, running the leads directly to the fan (but bypassing the fan's transformer) and then the fan will just run directly off the solar panel.

Thanks for any help everyone.

-m

2. Jul 12, 2008

### Staff: Mentor

Calculate the power requirement for that fan. P = V * I. What do you get? Something around 1 horsepower with those numbers ( 1hp = 750W approx. ). That's a lot of power to be getting off of a small solar panel. You will need several square meters of solar panel to power that fan -- is that really what you want?

Also, you will lose power in the conversion from the DC output of the solar cells to the 110Vrms input for the fan. A better solution would be to use a DC fan (preferably smaller), and use a DC-DC converter to convert between the solar cell output and the fan input.

Max insolation at noon is about 1kW/m^2, and simple solar cells are 10%-15% efficient, IIRC. You can do the math to figure out how many square meters of solar panel you need for powering various devices. Remember to factor in the low efficiency of solar cells, and multiply in about 85% for the DC-DC (or lower for DC-AC) conversion...

3. Jul 14, 2008

### marzelvane

Thanks for the reply! I was worried about that being the case...there is no way I want a solar panel that large lol. I'll just plug this damn thing in the wall.