Quiet, efficient fan for off grid living

[TheCasualTraveler]

I'm setting up my power source and appliances for a houseboat in the Florida Keys. My current task is to find the most efficient and quiet fan that's practical. I currently have 600 watts of solar and a bank of 6 golf cart batteries. I have a few questions,

Is a DC motor with permanent magnets more efficient than one without, with winding's?
If a brush-less motor is usually quieter than one with brushes, can you get a combination brush-less/permanent magnet?

To give you an idea where my head is at, I'm considering everything from a 12 volt auto radiator fan (but run on 6 volts to make it quieter) or even an array of small, super quiet computer cooling fans.

Thanks for any help.

[Bruce S]

I don't have a radiator fan to test with , but , since I work around broken computers  I have access to the 120mm x 120mm computer fans.
I've had up to 12 of these hooked up in parallel. The breeze was impressive.
I can say that you'll want to have or build a PWM to control the power. I always had to start them at 12Vdc, then PWM it down to 9Vdc.
This keeps them running nicely and doesn't suck up all the power from the 12 power source. Plus the noise is lower.
I made sure to match the current draw as closely as possible.

I may have a pic up here somewhere.

Hope this helps

Bruce S

[TheCasualTraveler]

Thanks Bruce,

9 to 12 computer fans was what i was thinking for 1 option. My luck with PWM's is that they tend to make things hum BUT that doesn't matter because if I need any speed control I will simply wire it to run on either 6 or 12 volts. I use a 12 v computer fan running at 6 volts to cool one of my inverters and it is absolutely Silent and cools better than the original that came in the inverter.

[JW]

I can vouch for this speed controller got good results with 12v

https://www.amazon.com/Controller-DROK-Regulator-Governor-Modulator/dp/B00DVGGWC0/ref=cm_cr_arp_d_pdt_img_top?ie=UTF8





JW
-edit- dam there out of stock I have 3 of these

[TheCasualTraveler]

Thanks JW but it's more than I need. 2 speeds, 6 and 12 volt is easy and sufficient.
Here's a link to the auto fan I'm considering, $24  any comments?
https://www.amazon.com/Universal-Performance-Electric-Radiator-Mounting/dp/B00T3TK3EW

[JW]

Whats the dia of the one you want.

Ive practically lived in Miami my whole life. LOVE THE FISHING down there...

I also have run crab traps. In the winter we would go for pink shrimp with a light and a dip net. Now i am living in Tennessee miss that so much. I have the prototype/example to the 8 cubic foot wire trap.   


JW

[MagnetJuice]

I agree about using computer fans. I have used many of those fans to cool a lot of stuff and to move air around. I used to put resistors in series to bring the voltage down but it is better to use a speed controller.

I found this fan at this place where I have bought a lot of stuff before. This fan pushes 200 CFM and they consume 23 watts. That is a very large amount of air. The rating of the average 120 mm computer fan is around 80 CFM or less. You wouldn't need as many of them to do what you want to do.

https://www.surpluscenter.com/Brands/Jaro/200-CFM-12-Volt-DC-Fan-16-1556.axd

As for a fan controller, here is a good one, I bought one of these and I use it to control the speed of a large fan that cools a large rectifier bank. This fan controller can control about nine of those fans.

https://www.mpja.com/20A-12-80V-DC-Motor-Speed-Control-Display/productinfo/35759+MD

MPJA has the same fan as the Surplus Center for $7.95 instead of $5.95.

Ed

[TheCasualTraveler]

JW, I'm looking at diameters from 8" to 14"

Magnet Juice, funny, I already bookmarked that same fan. I found an old one similar to it in my box of junk and use it wired to 6 volts to cool my inverter

[Mary B]

Could pair this with a small 100 watt inverter https://www.walmart.com/ip/Honeywell-TurboForce-Power-3-Speed-Air-Circulator-HT-900-Black/10980207?athcpid=10980207&athpgid=athenaItemPage&athcgid=collection&athznid=829495215_collection&athieid=v0&athstid=CS020&athguid=b9015b50-c13-16d2c3817ec978&athancid=null&athena=true I use that fan to move air for when I am heating with the corn stove and to move cold air into the living room from the kitchen AC unit. Run it on low and it moves a lot of air almost silently! Yes you lose some energy in inverter losses.

[MattM]

These are some of the quietesr fans available.  The 9" fans are near your specs, but its pretty low CFM.  $20.00 each
https://www.amazon.com/dp/B005OQN29Q/ref=psdc_11036291_t3_B07MCHLGC5

If moving air is more important than quietness, this is 1250CFM for the 10". $33/pair
https://www.amazon.com/dp/B06VWMJFHM/ref=twister_B07PNNH3S7?_encoding=UTF8&psc=1

[TheCasualTraveler]

Thanks Matt, I hadn't seen those fans in the first link. You mention 9" fans, but those say 120 MM which I guess is about 5". By 9" do you mean the fans in the second link?

One idea is to use the fans or fan in the second link but run on 6 volts which makes most 12v dc motors pretty quiet. All I need is a gentle breeze to make sleeping easier in the warm summer nights.

I'm still wondering if anyone can answer the question I posed at the start of this thread,

""Is a DC motor with permanent magnets more efficient than one without, with winding's?
If a brush-less motor is usually quieter than one with brushes, can you get a combination brush-less/permanent magnet?""

[MagnetJuice]

I found these links that give good information:

https://www.pelonistechnologies.com/blog/advantages-and-disadvantages-of-ac-fans-and-dc-fans

http://www.aspenmotiontech.com/technical-advantages-permanent-brushless-magnet.php#

Ed

[TheCasualTraveler]

Thanks Magnet Juice, just what I was looking for.