Fantastic Fan et.al. speed controller

[Shadow Catcher]

The efforts I have seen to slow down a Fantastic Fan have bothered me as in each case they involve using a fairly hefty resistor, and you have a bunch of energy wasted as heat. It is however the wasted energy bit that bothered me most. We are using a couple of computer case fans so this is pure altruism. I am NOT an expert in electronics so some one who is, step up to the plate

So what are the alternatives, there are various speed controller circuits using MOSFET ot FET's
http://homepages.which.net/~paul.hills/ ... sBody.html
http://www.omegaco.demon.co.uk/mecpjpdf/mecpj004.pdf

OR you can buy one http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0387965721

[astrotrailer]

I bought a pulse width modulator for my fan last year. I use it as a barely on solution. I crack one window away
from door in summer and run the temp controlled fantastic fan on slow to match opening in the window.
It helps keep the heat down on the hottest days.

It is very efficient. I can cut the amp draw down under 1/2 amp for a slow fan. It is much better than a resistor.

[madjack]

I bought a pulse width modulator for my fan last year. I use it as a barely on solution. I crack one window away
from door in summer and run the temp controlled fantastic fan on slow to match opening in the window.
It helps keep the heat down on the hottest days.

It is very efficient. I can cut the amp draw down under 1/2 amp for a slow fan. It is much better than a resistor.

errrrr, got any kind of a link...or any further info on make, brand, availability................

[astrotrailer]

I bought it on Ebay last year. I just searched Ebay again just now and found this:

http://tinyurl.com/38ad297

$16 + $8 shipping. It handles 6.5amps which is twice the Fantastic Fan's requirements. The wiring diagram is at the
bottom of the page on the link. Last year I paid $20 + $7 for shipping. Pulse width modulation works by generating
a DC square wave duty cycle from 0 to 100%. The unit in the link clocks pulses on and off at 30 Khz.

[astrotrailer]

I forgot to credit this site for the PWM idea. It is from the sticky thread for slowing down a fantastic vent.
It also works great as a dimmer for 12 volt DC powered LED lights. I have trailer set up that I can put the
lights or the fan on PWD controller by moving a couple of jumpers. Sometimes I like to run my red LED
lights low when at a star party to save night vision. I may just by a 2nd one so lights and fan have one
dedicated for each.

[madjack]

I bought it on Ebay last year. I just searched Ebay again just now and found this:

http://tinyurl.com/38ad297

$16 + $8 shipping. It handles 6.5amps which is twice the Fantastic Fan's requirements. The wiring diagram is at the
bottom of the page on the link. Last year I paid $20 + $7 for shipping. Pulse width modulation works by generating
a DC square wave duty cycle from 0 to 100%. The unit in the link clocks pulses on and off at 30 Khz.

...thank ya...thank ya very much............................................................

[eamarquardt]

I get a kick out of this forum. A waze back using resistors to slow down a fantastic fan was discussed and I suggested a PWM controller. As I recall the only comment on my suggestion was about the size of the heat sink on the PWM I posted a pic of and how much energy it must need to dissipate (I think it was a 30 amp module).

I think a PWM has to be more efficient than a resistor (and easier on motor windings) no matter what size heatsink it has on it.

PWMs are cool (or less cool if you use one to slow down your fan)!

Cheers,

Gus

[madjack]

Gus, somehow I missed the PWM posts and I knew to save power, a resistor added to the circuit was not the way to go...the PWM are the way to save power in smaller batteries(or even big ones)..........
madjack

[Arne]

I'd be more concerned with the resistor draw if I wasn't always plugged into 'something', either shore power or my generator.

plus, the only time it draws is when it runs. Never had a problem, but I can see if someone is camping off the grid, it might be useful to use something else.

I ran the fan one night 3 weeks ago with it cycling off and on camping on a hay field. I started the gen and found the battery was still show it would not take a charge from the battery tender.

The battery is a deep cycle from a medical scooter, weighs about 27#, do not know the ah on it.

I 'think' the 10 ohm resistor uses 0.5 - 1.5 amps.

[astrotrailer]

I use a DocWattson to monitor load. I can slow my fan down to a point were it draws 0.30 amps.
Below that and the blades stops. The 0.30 amps is the fan and PWM total draw. 0.6- 0.7 is a
more useful setting. It allows me to run the vent with the cover almost closed, (enough to
keep the rain out), but not so much air movement to create any audible noise. I keep
the vent set this way when I leave the trailer parked at home. The temp setting cycles
the fan on and off as needed to keep it from getting to stuffy. The solar panels keep
the batteries topped of so I don't have to plug the trailer into a electrical feed. I have
never plugged the trailer into the grid when camping.

[mclassing]

I can vouch for the PWM solution. The slowest setting on our Fan-tastic fan drew nearly 3 amps and drained the (smallish group 24) battery in just two nights of running.

I purchased the following controller on ebay.

http://www.ebay.com/itm/CCMHCW-DC-12V-40V-400W-10A-Adjustable-DC-Motor-Speed-Controller-PWM-Controller-/221255535007

In installing the new controller, I found that the old controller was merely a rotary switch with "wire wound wasting resistors" to slow the fan. The new control is installed in the same cavity which took some modification and finagling to get everything to fit. The good news is that this cavity is open to the fan flow and has a screened cutout above where the wire resistors used to be. Hopefully this will keep the new controller from overheating.

The net result is that now only full speed consumes 3 amps. The middle-to-slow setting draws < 1 Amp. The lowest setting draws about 1/4 Amp.

The only drawback to how I wired this is that the controller is always on. I use the reversing switch to stop the motor. The controller draws 10 mA at it's highest setting and 20 mA at it's lowest setting. I didn't get this backwards; I checked it twice.

Since there is a fuse upstream, I might come back later and replace the fuse holder with a proper shutoff switch. As it sets, I've estimated that it would take four months with no external charger attached to draw the new 100 AH battery down 50%.

This new control and the upgraded 100 AH battery, will hopefully be enough for us to make it through four consecutive days of boon-docking this summer.

[dales133]

How much modification did it take? And do you think heat might pose an issue?

[mclassing]

How much modification did it take? And do you think heat might pose an issue?

Dale (presumably),

It took me longer to work things out in my mind than it did to modify the space. The plastic is a bit thicker where the old control is bolted through the plastic. I cut this down with the Dremel tool and also pared it down with an old razor knife / paint scraper.

I was able to hot glue the controller board assembly to the plastic. There was also a tab that I was able to glue it to for vertical stability.

I opted to keep the wiring very simple -- this is why the controller runs continuously.

All told, I have an hour or so of discovery and planning and about an hour and a half to two hours in execution.

You might be able to find a smaller controller and make fewer mods.

I really don't think that heat will be an issue. The old rheostat-style control also produced heat -- and there are facilities to deal with this.

Hope this helps.

Mike