This guest post is by Michael C and entry in our non-fiction writing contest .
Recently someone wrote about the O2 Cool battery operated fan. I liked the size of the fan (10 inch) and the battery operation. I was impressed enough with the review (on MD’s web site) that I went through the (MD’s) bookmark and looked at a couple of versions at Amazon. I noticed (and remembered from the review) that fan came with an AC adapter which convinced me to buy one. The AC adapter was not as useful to the reviewer as the D batteries and the adapter did not interest me much either. The jack on the side of the fan was another matter – it meant that I could power this fan with “external” power sources.
The power input for this fan is 12 volts, I can connect a 12 volt car battery to this fan or a small solar panel. The note next to the jack shows “500 ma” which is half an amp and the icon shows a negative ground. That negative ground is the shiny outside of the “N” style connector that plugs into the jack. I had recently bought a 10 Watt solar panel at Amazon for $70 (USD) that would work for the (0.5A x 12V=) 6 Watt fan.
The prototype is shown in the picture being tested during partial (notice the lack of shadows) cloudy skies. By prototype I mean that I need to put a longer cord on the panel so that the fan can be in the shade (with me) while the solar panel is in the sun. The 10 Watt panel gives me some extra power for the fan during cloudy weather, it seems to really rev up during sunny weather. In a “grid down” scenario this simple setup can work – with no batteries, the solar panel will last for decades to power other items too.
Of course, a small sized RV/Marine battery could be added to the setup to store the extra power that the fan cannot use. If the fan is on “Low” then the fan uses less than half the power that “High” takes. The solar panel will be facing the sun all day while you may have the fan off. In this case a battery will “take up” the extra power from the solar panel. A simple diode, to protect against panel damage and battery discharge, for a 10 Watt panel is 2 amp at 25 volt. A charge controller is not needed for a simple setup with a small solar panel. The battery may even need additional charging, from a car battery charger, if the fan is run constantly.
One last note – the fan can be powered by DC power adapters if you do not have the AC power supply handy. The DC adapters usually come with different “plugs” and have different selectable voltages. Using 9 or 12 volts will move the fan fast, 4.5 to 7 volts the fan moves slower. The fan runs slower and quiet, just a breeze. Just using the selectable voltage as a speed adjustment and it works with high and low fan speeds.
This contest will end on October 10 2012 – prizes include:
- First Place : $100 Cash.
- Second Place : $50 Cash.
- Third Place : $25 Cash.
Contest ends on October 10 2012.