Introduction: Solar Powered Ceiling Fan (Chirstmas Gift)

I made this project for a friend who is a bit down on his luck and living in a small community with no power, water, toilet or pretty much anything else you would expect in a western country. There are a number of permanent residents living in illegal shacks, caravans, buses, shipping containers or camper-vans and a number of others who stay for a few weeks or months of the year but usually leave before the hot weather as it can get to 45 degrees C (113 F) for days at a time. The area is known locally as foot rot flats and is not unlike a small version of slab city in the US.

Back to my friend in his corrugated iron dirt floor shack, it gets really hot in there, so I thought I would make up a ceiling fan that would run off a solar panel.

Step 1: Stuff You Will Need

The heart of this project is a treadmill motor. They are a permanent magnet dc motor and are rated at 180 volts and 4700rpm. We will only be running it at about 15 volts and they run nicely off a 12 volt solar panel at about 400 rpm. I picked up a treadmill at the local tip and also found an old ceiling fan, so the motor and blades were removed.

If you cant find a motor they sometimes come up on ebay priced from $5 - $70

Shopping list

  • Treadmill motor
  • Ceiling fan blades
  • 12 volt solar panel 40 watts like this one
  • Wiring
  • switch
  • tube to make a motor mount
  • Nuts bolts and screws
  • paint

Tools

  • 5mm drill
  • 6mm tap
  • centre punch
  • hole saw
  • volt and amp meter
  • CAD program or ruler, paper and compass
  • general workshop equipment

Step 2: Remove the Flywheel

This bit is easy just remove the grub screw inside of the flywheel and the screw in the end of the motor, and the fly wheel will just slide off. save all the screws for later

Step 3: Make a Paper Template

The mounting point for the blades must be really accurate, or the fan will be out of balance and wobble. This would not only make an annoying noise it would also waste power as energy is put into shaking the fan to death rather than spinning the blades. I make my template using a CAD program but if you are handy with a compass and a ruler you could also make one with out a computer.

You might want to think about how many blades you would like on your fan at this stage, the more blades on your fan the more load will be on the motor and more watts you will need to drive it.

I found three blades with a 40 watt 12volt panel was about the same as a domestic AC ceiling fan going flat out. Using a 100 watt 24 volt panel was like a industrial fan and is probably a bit silly inside, as stuff started flying around and it started getting a bit noisy.

  • For three blades draw 2 circles one a 30mm the other 110mm
  • If using CAD draw one line from the centre and duplicate 3 times around the centre. you can then chose the correct size paper and print in true scale.
  • If using a compass, after drawing the 110 mm circle don't adjust the compass, you can then mark out six points around the circumference of the circle and chose ever 2nd one for the mounting point of the blades.
  • Check out the photos if your not clear on how to do it. (The template was drawn with a a marker pen for photos clarity, in practice you would use a very sharp pencil for accuracy.)
  • You can then carefully fold the paper in half and cut out the centre
  • Check the blades for fit and most flywheels will have balancing holes you will have to avoid

Step 4: Drill and Tap the Flywheel

Once the template is in the correct position three of the mounting points can be centre punched and drill with a 5mm drill. I found the fan on the back of the flywheel was interfering with the drill so it was removed. The flywheel is cast iron and quite soft, so drilling and taping with a 6mm tap was quite easy.

Once the first 3 holes are drill the fan blades can be fitted and the next 3 holes centre punched as shown in the photos.

The blades can then be removed and last 3 holes can be drilled and taped.

Step 5: Reverse the Pitch on the Blades

Now you don't have to do this step if you don't want to but I tell you why its a good idea. The treadmill motor normally runs counter clockwise which is the opposite direction to a normal ceiling fan. Now you can just change the + and - leads around and make the motor run backwards and your fan will work correctly, but on the all the motors I've found, the brushes make a clicking noise when the motor is reversed. The motors are clearly not designed to run backwards and I think it will probably wear the brushes out quickly if run in reverse.

Back to the blades, Just grip each blade in the vise and twist them the other way around try and get them all the same

Step 6: Marking Out the Motor Mount

The motor mount is just a piece of rectangular tube with some holes drill in it Some of my students struggle with drilling two holes to line up with two bolt holes, this is how I do it.

  • Paint the steel with a black marker, and use some digital callipers to scribe a line down the centre of the steel.
  • Use your callipers to measure from one side of the hole to the same side of the other hole (see the photo)
  • You can then mark out the centre of the two holes,centre punch and drill them.
  • A hole saw is used on the back, so the bolt can be dropped it and the end cut on an angle to make access easy for the second bolt

Step 7: Wiring Up and Testing

The motor leads can then be extended by soldering and length of wire to it and using heat shrink to insulate everything. A hole saw was used again and the wire threaded up the centre of the tube to keep everything tidy.

With a 12 volt 40 watt panel in full sun it was drawing 1.65 amps at 17.46volts (28.8 watts).

After increasing the pitch on the blades I was able to get a little more air flow and at 1.87 amps and 16.0volts it was pulling around 30 watts. I think its about as much performance as I'm going to get considering, solar panels are rated at 25 degrees C and are a bit optimistic, there performance also drops off with heat, cloud, dirt and the time of day.

After comparing the fans in my house I got a similar amount of air flow as if they were turned on high. And with a 24 volt panel its awesome, papers and crap are gone!

Step 8: Paint

Paint will make any project look better. So after sanding off any shape edges and lose paint, the fan was wiped down with acetone and the back of the motor taped up to prevent paint entering and gumming up the works. I had some cream coloured paint in a spray can, and I gave it three coats.

Step 9: Installation

Installing the fan is easy just screw it to the ceiling and run the wire outside to your solar panel. A couple of the local residents gave me a hand, and they were so appreciative, they couldn't believe that I had made it for them. For many of them Christmas is not a happy time of the year, all have financial problems some are estranged from their family, or have drug or alcohol problems. It didn't take long for a number of locals to come out and sit under the fan even a passing dog came in and lay down under it.

When wiring it up you have a number of options to power the fan.

  • Power directly from a solar panel
  • Power from a battery and use the solar panel to charge the battery.
  • Use excess power from a existing solar charging system. (see the diagram)

After discussions with the residents we chose the 3rd option as they had a large array of panels but the battery bank is in need of replacement as it runs flat quite quickly.

This would mean the fan will only run when the sun is on the panels, the battery would not see any extra load, and they would not have to tie up another panel just for the fan.

The fan was wired between the solar panel and the regulator, and after a few test it was found that in full sun the the fan was running on 19 volts and the battery will still getting still getting up to 15 amps (12volt system).

This works well as the regulator turns the load from the panel off and on the fan speeds up using any extra power from the panels.

Comments

author
Kafukai (author)2014-12-30

This is nice and save energy!

Why didn't you bought a 12v ceiling fan? it could save you the assemly process.

P.S

If you'll install some heat insolation on the wall and ceiling you wouldn't suffer so much on summer or winter.

author
liquidhandwash (author)Kafukai2014-12-30

I haven't seen a 12 volt ceiling fan that size for sale in this area. Its not my place to install insulation,the resident has been asked if he wants to, but it doesn't seem to be a priority for him. (It hard to help people who wont help themselves)

author
Pretired (author)liquidhandwash2016-08-23

In place of insulation inside could they put a bit of soil and see if grass or weeds might grow on the roof, that has an amazing cooling property via evaporation. As long as the roof is strong enough of course, The storage containers would work especially well with that.

author
liquidhandwash (author)Pretired2016-08-23

Hi pretired. The roof is a bit rickety, and it can get very hot here over 45 C have a look at

https://www.instructables.com/id/Solar-Powered-Air-...

I made it for the same group of people who are basically homeless

author
Pretired (author)Pretired2016-08-23

Just noticed how old these posts are, sorry for resurecting this thread.

author
Kafukai (author)liquidhandwash2014-12-31

I've checked up a little, and a fan that size is not cheap. So you did the right choice :-)

For the people who own the place, as you said it their own problem to fix.

author
AtypicalGeek (author)2015-06-20

What a great project and kudos for working with the people that need a little extra assistance. The fact that you attempt to teach, involve, and instill a feeling of ownership in our fellow human beings is commendable. Although your are concerned with those that will not help themselves, you obviously make a difference with those who want to better themselves!

I liked the simple explanations of how and why this fan project works so well. I hope to see more 'ible as you find new ways of helping yourself and/or others!

author
xxlauraxx (author)2015-03-18

This has a sweet back story, and it's a well documented 'ible. Thanks for sharing.

Speaking of Slab City, I just watched an excellent documentary called American Nomads. The filmmaker spends some time in Slab City. I highly recommend checking it out: https://www.youtube.com/watch?v=_QKbIb8wcz0

:)

author
liquidhandwash (author)xxlauraxx2015-03-18

Thanks laura, Ive seen a few Docs about slab city but I haven't seen that one.

Im currently working with a family who are living in "the flats" and we are going to build a solar powered air conditioner, Its kind of hard, to help them out without resorting to hand outs. So I go out there do a little bit, and ask them "could you just make this bit?" Sometimes it works.

Just trying to give them bit of ownership for the project.

author
Uncle Kudzu (author)2014-12-28

Well done! Thanks for sharing.

I guess I'll be on the look-out for a treadmill motor now...

author
Robibame (author)2014-12-28

awesome

author
Chickim (author)2014-12-26

Great idea that can be used for anyone off grid or wanting a way to save some money. You are a special person for making such a gift!

author
liquidhandwash (author)Chickim2014-12-26

thankyou

author
lfilek (author)2014-12-26

very nice video, adding a batterry would make the performance better I think

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