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Re: Pi4 Cooling

Posted: Wed Aug 07, 2019 11:57 am
by dpawson
jbudd wrote:
Wed Aug 07, 2019 11:54 am
There other cases on Aliexpress which show the fan wires connected between 5V and 3.3V GPIO pins too. I don't think that's a good idea.
I guess whoever produced the images just plugged them in at random.
Not nice - Is GPIO the only place we can tap 5v on the board? Imples @rpi only ever expected one aux item to be connected at once?
I think you're right about Aliexpress though. All the other fans take the GPIO power. Thanks for the heads up

Re: Pi4 Cooling, fan not powered from GPIO?

Posted: Wed Aug 07, 2019 12:13 pm
by alphanumeric
dpawson wrote:
Wed Aug 07, 2019 11:47 am
exartemarte wrote:
Wed Aug 07, 2019 10:13 am
dpawson wrote:
Tue Aug 06, 2019 2:51 pm
Fanshim looks pretty neat. Are the GPIO pins still usable 'above' the n pins used by the fan please?
A bit cockeyed, but still usable?
It depends on what you mean by "usable". They're certainly accessible - the shim is very thin and is not soldered. You could connect to the pins with a 40-way ribbon connector or with individual Dupont-style connectors. Some pins are used to control the fan, however, and are therefore not available for other purposes. I'm not sure which they are, but you might find that information on the supplier's website.
dpawson wrote:
Tue Aug 06, 2019 2:51 pm
Is there a fan powered by a.n.other means than GPIO?
I haven't come across one, but there's nothing to stop you powering a fan from any appropriate power source. It would be permanently on, of course.
Thanks for that... I'm told that the fanshim Fan and Sense HAT won’t work together, because Fan SHIM uses one of the I2C pins for fan control.

Ah well.
https://pinout.xyz/pinout/sense_hat#
and
https://pinout.xyz/pinout/fan_shim#

Other than BCM 3 (wake) I don't see any conflicts. Whether it works depends on whether the wake signal messes with i2c. i

Re: Pi4 Cooling

Posted: Wed Aug 07, 2019 12:22 pm
by dpawson
The conflict info came from Pimoroni, so I guess I must accept it.

Re: Pi4 Cooling

Posted: Wed Aug 07, 2019 1:38 pm
by davidcoton
jbudd wrote:
Wed Aug 07, 2019 11:42 am
One of the many aluminium cases on Aliexpress shows fan wires connected to the POE header pins. Presumably two of these pins are connected to 5V and Ground.
No, they are not. They are only for extracting power from the Ethernet cable. The POE power is applied to the Pi through GPIO header pins.

Re: Pi4 Cooling

Posted: Fri Aug 09, 2019 5:37 pm
by pica200
I have done some testing with this case: https://www.ebay.de/itm/New-CNC-Aluminu ... 2321943875

With included thermal Pad and no fan it reaches 78-80°C. Got Arctic Thermal Pads in the mail and replaced the old one and boy does it make a difference. Now it's stable at 68°C without fan! If anyone else buys such a case make sure you buy good quality thermal pads because the china pads are crap.

All tests were done with cpuburna53 at stock clock and no overvolting.

Re: Pi4 Cooling

Posted: Fri Aug 09, 2019 5:41 pm
by trejan
pica200 wrote:
Fri Aug 09, 2019 5:37 pm
I have done some testing with this case: https://www.ebay.de/itm/New-CNC-Aluminu ... 2321943875

With included thermal Pad and no fan it reaches 78-80°C. Got Arctic Thermal Pads in the mail and replaced the old one and boy does it make a difference. Now it's stable at 68°C without fan! If anyone else buys such a case make sure you buy good quality thermal pads because the china pads are crap.
Not surprising it is awful. The thermal pads I got with my case had one side covered with regular double sided adhesive tape like you'd get from an office supply shop. Their instructions were to peel off the protective layer from both sides and then stick the side with adhesive onto the SoC.

Re: Pi4 Cooling

Posted: Fri Aug 09, 2019 6:36 pm
by pica200
Yeah, ideed. One side was covered in this nasty adhesive. That took a bit to get off the SoC even with 99.9% isopropyl alcohol. The Arctic pads are really good and you get a whole mat of 145x145mm for like 10€. Probably gonna overclock a little bit later but then i need to get a fan since it will surely reach the throttle limit with overclock.

Re: Pi4 Cooling

Posted: Fri Aug 16, 2019 2:27 pm
by cspan
jamesh wrote:
Thu Jul 18, 2019 4:08 pm
It doesn't need much airflow of the board to cool it quite dramatically. I use the board with no case, and just the airflow around my desk keeps it to 55 or so at idle. Moving it to vertical orientation can drop it another degree or so, as the hot air flow is a bit more efficient rising past the board.
Just a tangential point of reference here ... I noticed an interesting temperature differential on the Pi Zero W that I had just set up with pi-hole yesterday.

It's powered from my router via a short USB to micro USB cable (power only; the cable is an odd one that apparently doesn't do data), and laying atop it while I browse, it gets to 47C. If I instead let it hang off the back of the router in the air (behind my desk, which has an overhang such that it has about 5" clearance to the rear of the desk, and 8" clearance to the room's wall), the Zero W runs at 38C. That struck me as a pretty big difference to get the backside of the Zero W free in the air, vs. laying atop a router.

So for those running a Pi 4 without fans, I can see how orienting it so that it's up on edge could have some advantages. In the air, even more so, but IDK if that might strain connectors. It sure could be inconvenient if you were plugging in and unplugging stuff periodically.
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Re: Pi4 Cooling

Posted: Fri Aug 16, 2019 2:34 pm
by dpawson
A fully wired rpi 4 doesn't hang (other than from all the wires).
With Raspberry pi kbd as well, there's little room to hang it anywhere.

I settled on a fan and it's working.

Is there a command line (bash) tool I can use to monitor the temp please?

Re: Pi4 Cooling

Posted: Fri Aug 16, 2019 2:49 pm
by cspan
dpawson wrote:
Fri Aug 16, 2019 2:34 pm
A fully wired rpi 4 doesn't hang (other than from all the wires).
that's actually what I meant
dpawson wrote:
Fri Aug 16, 2019 2:34 pm
Is there a command line (bash) tool I can use to monitor the temp please?
perhaps

vcgencmd measure_temp

Re: Pi4 Cooling

Posted: Fri Aug 16, 2019 3:26 pm
by dpawson
thanks, yes.

https://linuxhint.com/raspberry_pi_temperature_monitor/ pretties this up a bit.

Re: Pi4 Cooling

Posted: Fri Aug 16, 2019 5:56 pm
by billw
It seems a lot of people are using fans with their Pi4, but for me having it with no fan was a high priority for silent 24/7 desktop running. A case with its top off and a better heat sink really works fine. It just needs to be mounted in a way that is safer than exposed loosely sitting on a desk. One good way if possible is to mount the Pi on the monitor stand column. I used a heat gun to bend some plastic sheet around a form sized to fit my monitor column and mounted Pi4, SSD, USB hub and power strip on the plastic. I can unplug the HDMI and ethernet cables and short monitor power cord, and in less than a minute it all comes off as a single unit. But a commercial case with top off and other parts could just as well be silicone glued somewhere out of the way directly on the monitor back or stand.

I got an ebay 40mm x 40mm x 11mm heatsink which had no pad or sticky. I could have used arctic pads, but as an experiment, I mounted it with a small amount of thermal adhesive on the four corners of the CPU and a traditional non-adhesive low thermal resistance heat sink compound spread across the middle. I didn't want permanent adhesive all the way across in case I would ever want to try to remove the heatsink. I avoided covering the PMIC by cutting a notch in the heatsink with a hacksaw. I pressed the heatsink straight down to minimize smearing the compound into the adhesive and put a small weight on the heatsink directly over the CPU while the adhesive cured. After curing the heatsink seams secure and works great, but I've not yet tested what it would take to break it loose.

Running the Explainingcomputers stress test in a 26C ambient room, this is what just a little air flow in the room on a larger heat sink can do:

Code: Select all

	  	ceiling		ceiling
still air	fan low		fan med
-----------	-----------	-----------
temp=51.0'C	temp=46.0'C	temp=44.0'C
temp=59.0'C	temp=54.0'C	temp=51.0'C
temp=63.0'C	temp=56.0'C	temp=54.0'C
temp=66.0'C	temp=56.0'C	temp=54.0'C
temp=68.0'C	temp=58.0'C	temp=56.0'C
temp=68.0'C	temp=59.0'C	temp=54.0'C
temp=69.0'C	temp=59.0'C	temp=55.0'C
temp=69.0'C	temp=59.0'C	temp=55.0'C
No CPU fan and no worries about thermal throttling.
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rpi4-40mmx40mm-heatsink.jpg
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Re: Pi4 Cooling

Posted: Fri Aug 16, 2019 6:30 pm
by MisterEd
dpawson wrote:
Fri Aug 16, 2019 2:34 pm
Is there a command line (bash) tool I can use to monitor the temp please?
Also, if you want to see the temperature there is a panel applet. The advantage is that the temperature is shown on the taskbar all the time.

Re: Pi4 Cooling

Posted: Sun Dec 15, 2019 8:09 pm
by justahumanontheweb
the thermals are worse definitly than the 3b+, i ran mine with a C-size battery with the flat end on the cpu with some thermal paste and it worked fine (until it tiped over and shorted the GPIO pins, that is, don't try that at home for your own sake, lol)
now with the 4 even with a heatsink it manages to heat up like hell, i didn't have a fan on hand so i opened my thermo-electric fridge and took out the fan (its a 12v fan but it will run slower on 5v, on 12v its LOUD, also i don't use that fridge anyways) i connected it to the gpio header and it works like a charm, sucks that i brought a case, i thought it could run with it closed but NOPE

Re: Pi4 Cooling

Posted: Wed Dec 18, 2019 2:14 am
by pica200
justahumanontheweb wrote:
Sun Dec 15, 2019 8:09 pm
the thermals are worse definitly than the 3b+, i ran mine with a C-size battery with the flat end on the cpu with some thermal paste and it worked fine (until it tiped over and shorted the GPIO pins, that is, don't try that at home for your own sake, lol)
Wait what? Did you really just use a battery as heatsink? :shock:
Not a good idea. They can leak if you get the SoC up to temperature.

Re: Pi4 Cooling, fan not powered from GPIO?

Posted: Wed Dec 18, 2019 2:51 am
by HawaiianPi
dpawson wrote:
Tue Aug 06, 2019 2:51 pm
Is there a fan powered by a.n.other means than GPIO?
USB_fan.jpg
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Re: Pi4 Cooling

Posted: Wed Dec 18, 2019 3:11 am
by Imperf3kt
pica200 wrote:
Wed Dec 18, 2019 2:14 am
justahumanontheweb wrote:
Sun Dec 15, 2019 8:09 pm
the thermals are worse definitly than the 3b+, i ran mine with a C-size battery with the flat end on the cpu with some thermal paste and it worked fine (until it tiped over and shorted the GPIO pins, that is, don't try that at home for your own sake, lol)
Wait what? Did you really just use a battery as heatsink? :shock:
Not a good idea. They can leak if you get the SoC up to temperature.
More than leak, they can explode.