Solar-Powered Desktop Fans




About: Hi I'm Steve. I am a mechanical engineering graduate from Canada.

Intro: Solar-Powered Desktop Fans

Summer is almost here (in Canada) and it is the perfect time to harness the power of the SUN!

Cooling homes in the summer has quite an affect on energy loads and demands, so why not decrease your impact with solar powered fans! 

Actually, this can be used for anything that runs on 12 V DC . If you by a 12 V to 110 V inverter you can plug in pretty much anything that isn't too power-demanding. This would depend on the size of your storage battery though.

Step 1: Parts

You will need:

- 1 or more solar panel(s) that can output about 12 V
- rechargeable battery (I used an emergency car booster pack. These are good because they have 12 volt cigarette lighter plugs which are ideal for a computer fan.)
- cigarette lighter outlet adapter
- adapter plug that fits into the input of your battery (I was able to scavenge through some old adapters. The input is there for a 110V adapter that can be used to charge the battery using a regular wall outlet. Not very GREEN charging it that way though!! ) 
- breadboard (not very necessary, but makes things a lot more customizable)
- 1 or more 12 V computer fans
- shrink tube or electrical tape
- soldering iron (optional)

Step 2: Wiring

Solder or nicely twist together the positive and negative wires of the solar panels to the respective wires on the adapter plug. The solar panels should be connected in parallel.

Use some heat shrink tubing to insulate the wires or wrap the bare wire with electrical tape.

Connect the cigarette plug to wires to the positive and negative terminals of the breadboard or directly to the positive and negative wires of the fan.

Connect the fans to the breadboard. Fan 1 (the black one) had  the connector cut off so I connected the wires straight to the breadboard terminals. Fan 2 (blue led) had the regular computer fan connector on it so I connected it the breadboard using two pins. It may be a good idea to incorporate a switch.

Finally plug in the solar panel adapter into the input (charging) hole. 

NOTE: I know it says 300 A on the front. This is for the car battery leads that can be seen in the intro (barely) on the right edge of the photo. The cigarette plug does not output 300 amps!


Place the solar panel(s) in direct sunlight or stick them to a window. The battery may take a while to charge but it depends on the size of your solar panels and how many you have.

When the battery has enough of a charge, plug in the cigarette lighter adapter. There are LEDs on mine that indicate the amount of charge left. I didn't put a switch on the board so I have to unplug the cigarette lighter adapter in order to turn off the fans. Not too hard to add one though.

Enjoy your renewable source of cooling!

You can also use this to charge your USB devices.



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    5 Discussions


    6 years ago on Introduction

    Try this: get a Peltier unit (extracted from any old dead cooler - it's seldom the Peltier that fails) and have one fan blow the cold air towards you and the other fan blow the hot air away from you. This won't cool the room but it should cool your forehead. (I've been thinking about incorporating this and the solar panel into the canopy of our outdoor garden swing chair...)

    4 replies

    Reply 6 years ago on Introduction

    PS for outdoor use you simply plug the 12V computer fan directly in to the solar panel outputs. It blows when it shines which is when you need it. No battery required. I've also driven the Peltier directly from a panel and used it to cool my drinks when enjoying the sun in our back yard. (Of course South Texas sun is a bit hotter than Canadian sun so gives more power, but then you need more cooling so it all balances out...)


    Reply 6 years ago on Introduction

    Good ideas. I have checked the voltage coming from each solar panel and even at moderate sun intensity they put out about 20 volts each. I'm not sure if the fans can handle that much voltage. Will definitely try something with a Peltier though!


    Reply 6 years ago on Introduction

    Only one way to find out :-) But I suspect that 20V will be OK - it was for mine. Or... you can use a voltage limiter chip - 12 cents from your local Radio Shack and trivially easy to use.  One pin is ground, one is the input from the panel, and the third is the regulated 12V out. (or less, it steps down but not up - you need a Joule Thief circuit for that...).  The heatsink does get very hot though.  Maybe screw it down to the cooling fins of the Peltier and use some thermal paste.  It'll loose a little efficiency but may save you from a nasty burn.  On the other hand the hot side of the Peltier is probably nearly as hot as the voltage regulator so you're going to have to be careful anyway.



    Reply 6 years ago on Introduction

    Even though the panel puts out 20 volts, that's NO LOAD voltage. Notice how the voltage instantly drops when connected to a load (the battery?) If the fans use a little less than the panel puts out, it will reduce the voltage. BECAUSE these run on DC, they really don't care what voltage comes in. It will just control the speed. By the looks of it you're using 1 - 2 watts of solar panels, so either way the voltage may be high but the current is so low nothing crazy will happen. I would not go for a limiter chip because of the wasted heat energy. It's just not worth it.

    Good instructable and good luck in the green tech contest!