Pi 3 CPU Fan

[Kratos]

Hey everyone! I am looking for a small fan, one that fits directly on top a heat sink for the Pi 3 CPU. I plan on powering it by the GPIO pins. I am not too concerned about noise, but I do want the fan to be small enough to just fit on the heat sink. Any recommendations? Concerns? Links? Thanks!

Kratos

[Rive]

Hey everyone! I am looking for a small fan, one that fits directly on top a heat sink for the Pi 3 CPU. I plan on powering it by the GPIO pins. I am not too concerned about noise, but I do want the fan to be small enough to just fit on the heat sink. Any recommendations? Concerns? Links? Thanks!

Kratos

Depends on heatsink size. I am running a $6 12v desktop fan (70mm x10mm) on my gpio 5v rail (pins 4 and 6). If you are using one of those small tiny heatsinks (two on lift in first pic), a little fan on it will be near useless, and you will be lucky to shave 5C off your temps in a case.

You only need a heatsink on the SoC, Dont fall for the "you need 3 heatsinks BS".

Most of us that have went with heatsinks and fans, realized quickly that the larger the heatsink the better.

For cooling, thermal testing/benchmarking, see;
viewtopic.php?p=952371#p952371

for ex:

[Kratos]

Thanks for the detailed post you put together in that link. I shall be exploring my options...

Kratos

[MarkHaysHarris777]

I'm going to use this fan from amazom

I have a 30mm hole cut in the top of my clear case from Element14, and plan to mount the 40mm 5v fan in the top of the case above the heatsink on rubber fan mounts (very quiet, good airflow).

This fan is only 120ma and moves about 5.75CFM.

[Kratos]

I'm going to use this fan from amazom

I have a 30mm hole cut in the top of my clear case from Element14, and plan to mount the 40mm 5v fan in the top of the case above the heatsink on rubber fan mounts (very quiet, good airflow).

This fan is only 120ma and moves about 5.75CFM.

Thanks for the recommendation!

Kratos

[greenbag]

If you live in the city, ie: not stuck out in the boonies somewhere, then open the yellow pages or google for electronic component shops in your area. You should be able to get a 25mm x 10mm fan for less than $10.

[emptybee]

I bought this set: http://amzn.to/1WDOKsB

Needs a bit of dremeling to fit properly around the micro usb and 3.5mm jack connectors. Also a bit of a pain to remove the SD card unless you remove some material from there. I soldered an inline 15ohm resistor to the fan to slow it down a bit (was quite noisy otherwise).

If you already have a case it's probably best to DIY a fan from a electronics store rather than pay for this kit but I like that it had everything I needed. Just a bit of bodge work to perfect it.

[Alex_83]

I have a very small raspberry CPU fan as those found on ebay. In few months it became very noisy. I pulled off the sticker on the fan and put a little thick oil for lubrication in the axis, powered it while the oil was going deeper due to gravity (and put the sticker back)and it is working now as new without noise for about 10 months. I've tried it with anti-rust oils like WD-40 before but because these oils are not so thick and evaporate, my fan started making noise in a few weeks again.

[HawaiianPi]

For awhile I just used one of those USB port fans. The kind on a gooseneck flexible shaft. I plugged it into my Pi3 and bent it so it was pointing back and down, and even though my Pi3 was in a case enough air got through the various holes to keep it nice and cool.

[RaTTuS]

I have a very small raspberry CPU fan as those found on ebay. In few months it became very noisy. I pulled off the sticker on the fan and put a little thick oil for lubrication in the axis, powered it while the oil was going deeper due to gravity (and put the sticker back)and it is working now as new without noise for about 10 months. I've tried it with anti-rust oils like WD-40 before but because these oils are not so thick and evaporate, my fan started making noise in a few weeks again.

wd-40 is not a oil / lubricant it is a water displacement fluid....
best best is to use a flirc case like
https://community.zymbit.com/t/encrypt- ... rry-pi/150
or
https://www.aliexpress.com/item/New-Ras ... 05786.html

others are available

[Burngate]

wd-40 is not a oil / lubricant it is a water displacement fluid....

According to Wikipedia (which, like me, is never wrong)

The long-term active ingredient is a non-volatile viscous oil which remains on the surface to which it is applied, giving lubrication and protection from moisture

According to WD40.com

wd-40.png (34.51 KiB) Viewed 3958 times

[RaTTuS]

well , yes it's an oil and it can lube , but for things like fans it will not be good as the high viscosity will attract fluff and make it worse in the end .....
but noted

[HawaiianPi]

Here's a solution I just came up with last night.

My Pi3 is in a JBtek open sided case which had the fan on top.



That fan was too loud, so I went digging through my box of spare parts and found a very thin 40mm fan, and instead of mounting it on top of the case, I used a small brass spacer on one corner and mounted it between the SSD drive and SoC heatsink.

Side view:


Back view showing the spacer (corner of the Pi board by the red LED):


With the original fan my temps topped out at 74C when maxing out the CPU. That's pretty warm, but still below the 80C throttling temperature. However, after switching to the thin fan mounted between the SSD and SoC heatsink my temps have dropped to a max of 55C (-19C).

If you don't have anything mounted over the top of your Pi you could do something similar with a larger fan.

[HawaiianPi]

Expanding on my idea above a bit further, I dug into the spare parts box again and tried a few other fans. It turns out the spacing of the mounting holes on the Pi2/3 is nearly perfect for a 60mm fan. A quick test with some brass spacers on my Pi2.

.

OP_RPi_CPU_fan_2.jpg (75.33 KiB) Viewed 3789 times

OP_RPi_CPU_fan_1.jpg (85.87 KiB) Viewed 3789 times

.

And as an added bonus, it's now also a drone (WHOOSH!). Hard to control, though.

EDIT:
The Double-Tap!
.

RPi_Double_Tap.jpg (77.74 KiB) Viewed 3766 times

[HawaiianPi]

Okay, all silliness aside. This is a 25x10mm fan on a heatsink I cut down from a larger one.

RPi_small_HSF.jpg (61.57 KiB) Viewed 3765 times

This is the info on the fan. I don't recall where I got it (probably ebay).

small_fan.jpg (52.23 KiB) Viewed 3765 times

If your Pi3 is in a case, you could cut a hole in the case over the SoC heatsink and mount the fan on the case. That would allow for a wider selection of fans, because these tiny fans move almost no air.

[gkreidl]

Get a Flirc case and you don't need a fan.

[HawaiianPi]

I just found some 60mm 5V fans on Amazon, so this,

might not be as far fetched as I thought it was.

Actually most 12V fans work at 5V as well (just at a lower speed/CFM).