PV Gap

Vickie Said:

how do you make a solar powered fan?

We Answered:

You first need some basic specification information:

1. What size of fan (power) do you want? 50W would be quite big!

2. Do you want to run the fan when there is no sunlight - e.g during the evening?

3. How much time do you want to run the fan in the day and how many hours of sunshine do you expect

If yes to 2, then buy a solar cell, battery, two switches and fan. The cell should be for a slightly higher voltage than the battery (supplier will advise you on battery charging) and battery and fan should be of the same nominal voltage. A car battery (12v) would probably be best (cheapest) if not the smallest. Use your answer to 3 to decide on cell and battery sizes (watts and amp-hours respectively). The amp battery drain for 50 W will be 4A so a 40 amp-hour battery will give you 10h running time without charging

!f no to 2 then you can miss out the battery. The cell and fan should then be of the same nominal (full load) voltage.

Don Said:

Are there such things as solar powered desk top fans, if so has anyone used one and are they any good?

We Answered:

I've seen a Solar Powered Perspex Desk Fan sold as a self assembly kit for children interested in science and gadgets but good enough for adults to have on their desks :) It's priced at around £30.

Jason Said:

completely solar powered attic fans?

We Answered:

The easiest to install would be a gable end vent. Remove the existing end vent, install the new one, perhaps trim it out to look good.

Keep the solor panel vertical, this will keep snow and road grime off it. Don't worry about aiming it. Most panels need sunlight, not direct sunlight.

I wouldn't use the thermostat feature. There is just as great a need to vent the attic during the cold season as there is during the warm season.

The gable mount fans have long wires that allow you to place the fan in the gable and then mount the panel where it will get plenty of sun or stay out of sight.

Jordan Said:

Any luck with solar powered attic fans?

We Answered:

I had one installed and it works well. When it gets above a certain temp it kicks on and with that and the programmable thermastat my AC bill was less this year.