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Whats the current best VENT FAN?

wopachop
Explorer
Explorer
Tell me there is some unknown company who makes decent quality fans!?!? My buddy has a fantastic fan that is 1 year old and hes having to modify it just to work again. After the 1st motor died.

I see the maxxair lineup. The price makes me want to build my own. Which i did. A window unit pulling air through a home AC filter. Was cheap to make and works good. Just too loud utilizing a cheap radiator fan.

Has anyone found cheap and quiet 4" blowers? Thought about using those to blow through a filter and get nice clean cool air into the RV.
79 REPLIES 79

wopachop
Explorer
Explorer
Started messing around with a swamp cooler option.





landyacht318
Explorer
Explorer
Is the blower motor itself isolated from whatever you have it mounted to? Some soft silicone rubber bushings lightly compressed by washers sandqiching the the mounting feet and the screw itself unable to touch the fan's mounting feet?

As far as wind noise transmitted through the tubing, that is harder to address and will add some restriction.

Even though you have the filter, eventually the fan blades will get a fine layer of compacted dust and get more out of balance, and move less air. Cleaned it will move the same air for slightly less rpm and noise, and amp draw.

wopachop
Explorer
Explorer
You fellas are super clever. Have any idea to reduce noise? Maybe some foam like they use on microphones?

https://www.youtube.com/watch?v=yNmc5kBNpPE

wopachop
Explorer
Explorer
Getting closer to done. After much thinking i finally decided on where to drill the hole. Will be nice because the fresh air will blow right where i sit.

If anyone needs a rotozip style of spiral cutter i got lucky and Lowes has the $99 version on sale for $50 right now. The 5/32nd bit cut through the plywood like nothing. Have wanted one of those tools for many years.



landyacht318
Explorer
Explorer
I saw on some computer forum that guys were testing flow of various fans by timing how long it took to fill a 50 gallon trashbag and how taught it got.

This Might be a better yardstick than a anemometer placed in the flow of the vent.

Thanks for the data.

wopachop
Explorer
Explorer
I like the idea of homemade swamp cooling. Not against the dual push/pull fan configuration either. Was thinking the same thing with the blower outside pushing and computer fan inside pulling. Adjust each as needed.

For me personally it all comes down to asking if 0.25amps is low enough for low? Giving the 4" blower 12.00v still only turned it down to a 0.19amp draw. Motor ran smooth and sounded good at all speeds.

The filter does not seem to effect noise or airflow very much. The biggest airflow change i saw was using the 4" blower in pushing mode on low speed with the filter.

Here is an attempt to share basic clear to read data. All fans are sucking air and no filter. I have specs with both that are on the pages i posted earlier.

landyacht318
Explorer
Explorer
Don't be afraid of the push pull.

Since the Noctuas are so little amp draw, you could likely have your blower outside, running much less rpm than 0.3 amps less, with the Noctua pulling on the other side of it, for more air moved and less noise and amp draw.

My 3krpm Noctua did not enjoy the counter rotating feeder fan, 8Mm away from it, but 8 feet of ducting between the two fans in a push pull should do more for less, perhaps much less when dialed in via speed controls, with the optional turbo mode with both cranked up.

Also all that air you are pumping in needs an escape route. If yo ucan open some other window and hear the fans change rpm then there is still restriction to flow.

If you are in the desert and have access to a hose, put one of those misters on it over the auto air filter. Evaporative cooling works very well as long as the humidity is not high.

MEXICOWANDERER
Explorer
Explorer
Get a piece of cotton sheet approx 3' x 5'

Hanging it you'll have to become inventive. Involves a piece of clothesline and pinch clothes hangers.

Small powerful fans try and "punch a hole" through the cotton.

Even small amounts in airflow change are readily visible. This is very helpful if tweaking voltage.

It even revealed just how much air the Endless Breeze was pushing while on # 3 setting. Tip, the more off-vertical the fan pushes the whole sheet the more gross airflow the fan has.

Mother Fletcher's Do It Yourself Windtunnel Velocity Measuring Kit

wopachop
Explorer
Explorer
Got it setup like this for a couple days. Wondered how much sound would transmit through the ducting itself. Still deciding on the blower versus computer fans.

Might try mounting the 140mm fan in the center of the ducting. With a couple feet of duct on each side. That would allow for the automotive filter on the intake, and could mount the fan inside the cabinets. Instead of the computer fan being the end of the line. Because the original idea was to have the blower mounted outside the trailer to reduce noise.

wopachop
Explorer
Explorer
Found a thread that said this forum does not allow embedding so here are links.

Attwood 4" blower

Noctua 120mm 3000rpm

Noctua 140mm 3000rpm

wopachop
Explorer
Explorer
I agree the data sheet is very hard to read. Had to ask my friend if she had highlighters so i could try to make sense of it all. I will go through it and post easy to read specs.

Measuring the airflow was a bit tricky. Especially for the computer fans while using the air filter. Because i was measuring the exit speed of air out the fan and that speed varies greatly.

Would have been ideal to install the wind meter in the center of the tube.

landyacht318
Explorer
Explorer
The blower can consume 5.6 amps? Very hard to read the data sheet.

When it is dialed down to 0.25 amps is it moving much air?

Does it whine or sound a bit unhealthy as slow as it can go?

Does the filter make it louder or quieter at the same speed.

I really like the automotive air filter to the bilge blower idea, although 5.6 amps is considerably more juice than I would want to expend on ventilaton.

wopachop
Explorer
Explorer
Heres an example of the wind meter through a tube test. Its the 120mm pulling air.

Thats another topic of interest is pulling versus pushing. The computer fans i only tested pulling.

The 4" blower i tested pulling and pushing.

wopachop
Explorer
Explorer
This is the data i got. I like the right side page better which is day 2 and a litter more clear.

Overall i would say this:
1. The 4" blower has amazing range and power. Pulls 0.25amps on lowest setting.
2. The 120mm fan wins on efficiency. Seems to be just as powerful and move close to the same amount of air as the 140mm, with less power draw. Negative is the sound which is more high pitched. I wanted to use the 120mm but the noise it makes full blast is not pleasant to my ears.

3. The 140mm is more quiet. The sounds is less of a whine....more of a wind noise that blends and disappears into the background better. Pulls 0.66amps compared to the 120mm that pulled 0.33amps and they produced similar results with a basic wind meter through a tube test.