Reliable small 12VDC fan - which one to choose?
john_s
Posts: 369
I need some help to locate who supplies reliable mini-fans (size 40x40x10mm and 50x50x10mm ) of the type you might find cooling down motherboards or other electronic devices.
I'm in search for a proven and reliable type that will last running continuously 24/7 from 12VDC.
Plenty of cheap $3 fans but are they any good? I need a RELIABLE one...
Which one would you recommend to start with?
Thanks,
John
I'm in search for a proven and reliable type that will last running continuously 24/7 from 12VDC.
Plenty of cheap $3 fans but are they any good? I need a RELIABLE one...
Which one would you recommend to start with?
Thanks,
John
Comments
Also make sure the fan pulls cold air in and not pulling hot air out.
This keeps the fan cooler and extends the life of the bearing.
Redundancy greatly extends lifetime.
Duane J
I figure they might be the quite ones.... and that's one of the goals beside reliability.
What is the operating temperature range for your usage?
How much air do you need to move?
Vertical or horizontal placement?
Sound level?
It's moving parts and electricity pumped out of an assembly line no matter what you get. You won't find a lot of reviews online about fans that size. I can tell you from experience that if you want something to be reliable you monitor it or make it redundant. The brand isn't going to save you and you shouldn't rely on it entirely.
I went on Amazon.com and looked up 40mm fans. It was actually surprising to see what I thought would be bad quality fans with really good reviews. I'd spend the money on a sensor to monitor the fan and set off an alarm before I spent any extra on a fan. I've pulled tons of dead fans. The ones that run the longest are the high speed heavy duty large fans. Small fans were a huge mistake on the southbridge of a lot of computers. Video cards used to have super cheap small fans on them and they failed all the time too. Passive cooling seemed like a better option than some of the Smile good companies were pumping out.
This is a microcontroller forum. Why don't you get a 40mm fan with a tach lead and build a sensor? Will the space allow it?
Maglev doesn't depend of either ball-bearings or sleeve bearings for less friction. ... it uses magnetic repulsion. It is a neat concept, but as you go up in the amount of air you are pushing, it becomes less and less effective. So much depends on how much air you want to move and since 'best' presumes that the fan will move more air.. a ball-bearing fan is likely to be the heavy-hitter.
Sure the MagLev starts out frictionless, but as grime accumulates it too can have friction.. and magnets to attract magnetic grime from the air.
Frankly, I consider the 4 inch fans and anything smaller a joke, but there are indeed a lot of devices with tennie tiny fans, including my beloved notebook computer. Asus's first EEEpc had a better idea, the aluminum base of the keyboard provided cooling via being used as a massive heat-sink. Fans can only do so much.
The Quiet fans have grooves cut in the blades leading edge. It seems that creates turbulance that in turn reduces the noise output that smooth blades might produce. It seems to be the oppositie of what you would have thought should happen, but it works.
23deg C (room temperature)
1 - cube 250x250x100mm
2 - cube 300x3000x150mm
Both
Lowest possible (call it "humming" noise)
http://www.ebay.com/itm/321247300525?_trksid=p2048036 Sunon 40mm x 10mm magnetic bearing
Newegg.com is always worth a look because of the variety of fans they sell. This is a search for 40mm x 10mm fans.
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=40mm+x+10mm+fan+&N=-1&isNodeId=1
The smallest maglev fan I have (18mm) coincidentally I installed on a Asus EEEpc powersupply. I can post a picture if anyone is interested.
I am - please do post a picture.
The above link has a Sunon at 1.26 watts and another at 0.96 watts... 25% more power in the larger .. both 12v, both the same bearing.
It is all about the max air flow possible, not necessarily the volume size of the chassis and that takes power. Given your cube and your longer chassis, if you position your fans right.. both would have about the same air flow if the same fan was used. But you can make cooling worse by putting fans in sides that create dead corners to air flow.
The better and larger the heat sink for whatever the fan is supplementing, the more stable your cooling as the thermal mass of the heat sink makes both sudden drops and sudden increases in temperature less likely.
The more increased surface area of your heat sink, the easier it is for the fan to do its job. So, one should take a very in-depth look at good heat sinks if they think they need fans. Fans without good heatsinks are only going to do so much.
In local shops, I have seen a lot of expensive fans that make huge claims of superiority, but with lower watt ratings than the generic devices. I suspect these are for the fools that don't know physics.
If you can't find the watts, higher cubic foot per minute is an alternative measure. I am not sure that RPM counts for much. You may begin to notice a lot of nonsense with what the really expensive ones are advertising, instead of cubic foot per minute, they use cubic meters per hour.. maybe no watt rating, and so on. Buyer beware.
That Noctura at NewEgg is about twice the cost of the Silentx and underperforms in comparison.. a typical uber-expensive computer fan.
Believe it or not this little fan at about 1 CFM does a good job cooling it. Also when ever I replace a small fan less than 60mm I always use a Magnetic bearing type.