Variable Speed (PWM) Ceiling Fan Mod == 10 Bucks

MuttonChops

Problem:

Like many T@Bbers before me I find the factory installed 3-Speed Fan a disappointment and do wonder at times how NuCamp can work so hard on construction quality yet continue to install the base model fan like all the not-so-well-built RVs on the market.

Several folks have posted about upgrading their 1250 3-speed to a 14-speed using Fantastic Fan upgrade kit 7350 which costs about $150. I'd prefer to save that money for a future MaxxFan Deluxe (with built in rain shield). However while outfitting a new T@B with must haves (for me) a new fan quickly fell to the bottom of a long Amazon shopping list.

The Plan:

Use a PWM Motor Controller to replace the 3-speed power switch. The result would be a variable speed fan that can be much quieter than the original on speed 1 and draws half or less battery current. Plus installation time is about the same as the 7350 kit, well a little more to cut & solder wires. Cost ~ $10 for part +tax.

How To:

Not my original idea . . . Found a very complete post from 2015 on the wanderthewest.com/forum. PDF copy attached to this post.

A minor issue was caused by space limitations not seen on the 2015 Camper installation. T@B roof thickness is thinner (or the PWM Board used a bit larger). So instead of mounting the PWM Board vertical as in the article mine is mounted at an angle. It only fit in one specific orientation so the large heat sinks and capacitors could fit in the available space.

Early operation data is very promising. Fan running at a comfortable noise level, with gentle air flow has a current draw about one third as high as the standard 3-speed Low Setting [1].

* * Radio Off, Clock of Radio On, Standard baseline current included in the above numbers

The attached article should have everything you need to know.  If not ask, I'll attempt to answer.

BrianZ

This looks like a great mod that would solve one of our greatest disappointments with the T@B (the not-so-"fantastic"-fan when it comes to noise).  There's just one problem, or maybe I missed it, but I don't see any source listed for the replacement controller board.
PS: also, do you know what the wattage rating is for the controller?

Sharon_is_SAM

Nice job @MuttonChops!  Just so you know, nuCamp will install a Maxx Fan Deluxe with a build order.  

Tabaz

Thanks for taking this one on.  I've been searching for the $120 upgrade kit with the clamp style opening (the photo of your frame is the clamp style) for weeks - everyone (including Fantastic) is out of stock.  Please provide the WPM model number and source.  A few more photos showing your wiring and which corner the controller is located would be greatly appreciated.

BrianZ

Well, after a lot of searching on Amazon, I found this source which includes a review from 04/18 with multiple installation photos & diagrams in a Fantastic Fan..

https://www.amazon.com/RioRandTM-Upgraded-6V-90V-Motor-Controller/dp/B00F839VNQ

Haven't studied it thoroughly yet, but at this point it's not clear to me whether the function of the fan's reversible direction switch can be preserved with this mod? 
Not sure if we've ever really used it for anything but exhausting air.

PS:  I've also come across other reviews of PWM type controllers that people tried to use with a Fantastic Fan which didn't work satisfactorily due to a high pitched noise it caused in the fan, so not all are equal apparently.  I may try this one.

Tabaz

Brian - the "Questions Answered" section says it is only one direction.  I've only used my fan on the exhaust setting to remove air from the cabin.

DeltaPop

In the review section it shows the reversing switch in the circuit.

BrianZ

@Tabaz , that's probably what confused me, but as @DeltaPop points out, it is included in the diagram, and now I have seen in one of the review photos that it does appear to be wired through the reversing switch.  No reason to buy a controller with a reversing switch since the fan already has one built-in.

Tabaz

Waiting to hear back from MuttonChops before I hit the "buy" key.  This mod is slightly above my electrical knowledge pay-grade, so the more information I can get from you guys, the better!

MuttonChops

BrianZ said:

Well, after a lot of searching on Amazon, I found this source which includes a review from 04/18 with multiple installation photos & diagrams in a Fantastic Fan..

https://www.amazon.com/RioRandTM-Upgraded-6V-90V-Motor-Controller/dp/B00F839VNQ

Some cautions for the Review Pictures of the above PWM Controller:

  -  Notice how board placement is vertical and slightly taller than white plastic.  This will mount to the fan however the screws will not be fully seated.  Can not tell from pictures if the Heatsinks are larger which would make placing board at an angle impossible.

  -  The 3-Speed switch in my Fan had different connection tab locations.  Use a meter to confirm which tab is "switched +12V"

BrianZ said:

PS:  I've also come across other reviews of PWM type controllers that people tried to use with a Fantastic Fan which didn't work satisfactorily due to a high pitched noise it caused in the fan, so not all are equal apparently.  I may try this one.

Only noises I've heard are from the Fan. At very low speed sounds like it needs a bit of oil (which is not possible), at higher speed the air flow blade noise over powers the "need oil noise"

PWM Controller I used:

https://www.amazon.com/gp/product/B00QA6E4QO/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 

MuttonChops

SAM said:

Just so you know, nuCamp will install a Maxx Fan Deluxe with a build order.  

At the time I ordered my unit, December 2017, Factory answer to request for a MaxxFan installation was No.  They would only allow modifications to their standard inventory of parts.

My Dealer commented "NuCamp has changed their policy, again.  Seems they allow and do not allow this type of modification for no clear reason."  My guess it has to do with inventory control and production floor activity level.

pthomas745

There are many different PWM controllers on Amazon, with some having reviews of successful use with different fans....what would be the specs I should look for? 

MuttonChops

Tabaz said:

Waiting to hear back from MuttonChops before I hit the "buy" key.  This mod is slightly above my electrical knowledge pay-grade, so the more information I can get from you guys, the better!

My installation is nearly identical to the 2015 Article attached to the original post.

I will post additional pictures/details on my specific installation . . . need time to write up . . .

As for the Reversing Switch Discussion.  With correct wiring Reversing Switch still functions with the PWM Controller.

BrianZ

Thanks for your source & comments, @MuttonChops.  It looks like your board is about 1/8" less in length & width, which might make a difference, though the components are arranged differently. It might depend on how one orients & angles the one I found, as to whether it could fit. 

I did notice that vertical placement you mentioned & how the standoffs will shorten that distance, so it would appear that wouldn't work properly as they show it, as you noted.  I do see another way to angle it where components might fit around the plastic standoff, so I may give it a shot & see.

Good point too about the switch contacts - will have to check that.  Thanks.

MuttonChops

Additional Pictures & Information

The attached PDF has several pictures and instructions (sometimes detailed) as well has general notes/reference comments.  Expect it is a bit more than @Tabaz was requesting . . . be careful what you ask for.

Do use what is helpful & ignore the rest.

This PDF and the one written in 2015 (attached on original) should cover most everything.

Proceed at Your Own Risk
of course

BrianZ

A mod a day keeps boredom away!

JonW

Here's another alternative that works and doesn't cause the fan to make any unusual noises.  I did this to the Fantastic Fan in my teardrop and it's been working fine now for years.

Replace the speed switch in the fan with a 50ohm 25w rheostat like this one on Amazon.  Then you can just get a new plastic knob for it from the hardware store.   You can either solder the existing wires to it (cut from the existing switch) or use auto blade connectors.

Amazon also sells this one which includes a knob.

Easy peasey...

 

MuttonChops

JonW said:

Replace the speed switch in the fan with a 50ohm 25w rheostat like this one on Amazon.  Then you can just get a new plastic knob for it from the hardware store.  

Yes, gives you speed control.  Still generates more waste heat and won't reduce current draw as much as PWM approach would.

PWM controllers were developed to replace rheostats with a more energy efficient solution.

Tabaz

MuttonChops - WOW! Thanks so much for the detailed narrative and graphics. My PWM comes in Sunday. Based on your information, I feel confident to do this mod. People like you make this forum invaluable.

JonW

MuttonChops said:

Yes, gives you speed control.  Still generates more waste heat and won't reduce current draw as much as PWM approach would.

I've found the amount of waste heat negligable - doesn't even feel warm.  Also it does reduce current consumption although probably not as much as a PWM controller.  The big advantage IMO is no motor noise.

Tabaz

Just finished the "MuttonChop Variable Speed Fan Mod."  Works great - no noise (except the air moving through the blades).  A couple of observations. (1) the terminal positions on my PWM were different than those on his PDF page 7/8.  No biggie - just make sure you turn the PWM over to see the markings.  Then make sure the wires go to the terminals he has on page 7 (mine were "M -, M +, P -, P +").  (2) the only corner with room for the PWM is the one specified.  The other three corners have stuff in them.  (3) You must turn the old 3 position switch "on" in order for the new variable knob to work.  Simple mod with great results. Thanks MuttonChops for the great photos and instructions!

MuttonChops

Tabaz said:

Just finished the "MuttonChop Variable Speed Fan Mod."  Works great - no noise (except the air moving through the blades).

Excellent glad the project was uneventful. Real credit goes to the guy that wrote the yr-2015 article on a different forum.  I was just lucky to find it during a web search.

Tabaz said:

 A couple of observations. (1) the terminal positions on my PWM were different than those on his PDF page 7/8.  No biggie - just make sure you turn the PWM over to see the markings.  Then make sure the wires go to the terminals he has on page 7 (mine were "M -, M +, P -, P +"). 

Different on/off speed select tab positions is not a big surprise.  One of the PWM Controller reviews on Amazon was also different than the one installed on my fan . . . fantastic fan must have different suppliers.

Sorry the final diagram PWM Terminal names/locations were not correct.  I wrote that PDF document after the installation, had no reference picture, and guessed wrong.  But like the on/off speed selector switch double checking before doing is always a good idea.  * * * PWM Signal Type was at least correct for routing to the other fan locations. * * *

Tabaz

BTW, the reverse airflow switch works with this mod!! VERY happy with the results.

BrianZ

I am very happy too with my installation today.  I used the one that I referenced above.  It was a tight fit, but with a couple of part mods, it fit perfectly & works great.

I also installed my PWM motor controller at an angle, and with the two capacitors & a heat sink straddling the standoff & mounting hole.  Even then, I'm not sure it would have fit properly if I hadn't trimmed off & rounded the corners of the circuit board with a cutting wheel on my dremel tool.  There weren't any components there, just mounting holes in the corners, but I still sealed the cut edges with hot melt glue to insulate any exposed copper layers in the PCB.  I also trimmed & filed the outer corners of the largest heat sink in the corner.  Since this board was designed to run a wide range of voltages & currents that far exceed the limits of this fan motor, those trimmed bits would never be needed.
I'm looking forward to being able to run the fan at lower speeds while sleeping, thanks to the much lower noise levels made possible by this variable speed control range from full speed to zero.

BrianZ

@JonW, why would you choose a rheostat rated at 25 watts, when the fan can draw over 3amps & therefore more that 40 watts at 12V?  Granted, most people would want to run it at lower speed for reduced noise, but if run at full speed, wouldn't the rheostat exceed its rated power limit and risk overheating?

BrianZ

Out of curiosity, I temporarily removed my installed PWM controller, so I could try out the rheostat that @JonW recommended, just for comparison. 
I measured sound levels using the "Sound Meter" android app, and they ranged from around 27 to 53 decibels between slow & fastest speeds, nearly identical to what I measured with the PWM controller.  I would not place much importance on the actual decibel values, but instead on how they compare between the two devices, since it can vary with the microphone used, its placement, etc, but I measured both the same way, so the comparison is valid.  The range of measured sound levels was labeled in the app as comparable to being between a quiet library and a normal conversation.

The most noticeable difference in usage was that the useful range of speeds for the rheostat was compressed into the upper approximately 40% of the control knob's rotation range.  The lower 60% was a range of very slow speeds, probably too slow to move much air.  I also noticed that the knob does not turn smoothly like the PWM does, because of its design where a contact brush is raked across a wire winding around a ceramic "donut", so it feels rather stiff.  I'm not sure whether this is an advantage or disadvantage, maybe both, but just an observation.

After a few minutes of testing at various speeds, I removed the rheostat to check for heat.  I put my finger on the side of its ceramic body, and it was hot enough that I could only keep my finger on it for less that a second.  It was quite hot.  I never detected any heat from the PWM, but I would expect that, because it was designed for up to 1000 watts at 15A, so the fan motor's 3A at 12V is near the lowest end of the PWM controller's power range; where as the rheostat was operating well above its power rating of 25 watts.

My vote goes to the PWM controller, even though it may be a bit more work in terms of wiring & fitting into the space.

MuttonChops

@BrianZ;

While doing your rheostat test comparison did you happen to make any current measurements?

MuttonChops

Just completed a two night dry camp adventure using the PWM Fan Control.

Really liked how it worked " real - world "

BrianZ

No, @MuttonChops, sorry, I did not measure current.  And after putting that darn fan housing back together several times already, I'm not sure I want to do it again.  Getting that lid latch knob back on is never fun.
Glad to hear the fan mod proved it's worth for you.  I expect it'll be great just for sleeping as well as the power saving aspect.

Tabaz

Hey you guys - let's not get buried in the weeds. This mod is cheap, fairly easy to install, and works beyond expectations. It's time for MuttonChops and BrianZ to coordinate on a new mod for the benefit of us all.

JonW

 @BrianZ - good job on the comparison.  The rheostst rating was recommended by someone over on the tnttt.com forum and I just went with that for my teardrop.  After your analysis I’ll go with a PWM controller if I do this for the T@B.