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[DISCUSSION] Fans/Heatsinks/CPU Cooling Mods

Posted: Fri May 13, 2016 11:49 am
by chiark
Hi folks, my lp has arrived and it's working well. Quick question - on idle the CPU temps are around 70-80 degrees C, with an ambient of about 15... Strikes me that it might be worth adding a heatsync - has anyone looked at this?

[DISCUSSION] Fans/Heatsinks/CPU Cooling Mods

Posted: Sun May 15, 2016 4:46 pm
by ermingut
I was looking at some HD video and after 15 minutes video playback started skipping frames and I noticed that generally computer was not as responsive as it should be.

Later on I discovered that CPU was running only around 600 MHz or even less. I checked CPU temperature and it was around 83 degrees Celsius. I have my LattePanda in acrylic box. I cooled down my panda with very lo tech solution - the hair dryer - :D and my Panda was back on 1.4 GHz sometimes even more.

The obvious conclusion: LattePanda must be additionally cooled down or in more spacious enclosure for proper temperature dissipation.

One question for LattePanda team: Will additional heat sink on metal surface where processor is located make any diference regarding cooling or I will have to find proper fan for cooling.

Re: CPU temperature high

Posted: Sun May 15, 2016 10:01 pm
by acasta
Similar problems here: I didn't push my LP as far as to become unresponsive due to downlocking, but I noticed quite elevated temperatures in my plywood-LP-box.

So, my question is:
There are two large metal shields, one on top, one on bottom of the LP board. Is it a safe bet to assume, that heatsinking only the top plate should do away with thermal issues, or is a secondary heatsink on the bottom advisable? (Could mean that I'd have to replace the plywood case, but that wouldn't really hurt...)

And, secondly, as I'm not an electronics guy: Are there pins available to drive a small fan? I've got a "RasPi fan" (5V/200mA) lying around, but LP documentation states that no pin could deliver more than 40mA. Did I jump to premature conclusions, or is there really no way to power a fan without some external power supply?

Best regards, -ac

Re: CPU temperature high

Posted: Mon May 16, 2016 6:16 am
Mine idles at 44c and maxes at 85c.
The temperatures don't change if you use it outside of the case.

I 'installed' a heatsink on the top metal shield, CPU temps dropped by 1c.
I've removed the top shield to find that there is no thermal paste between the chips and the metal.
Also the CPU is on the bottom side not the top, I haven't tried adding a heatsink to the bottom or the use of thermal paste as I don't have any.

I'd be interested to see if anyone has tried this.

However, even with these high temperatures there hasn't been any slow downs. Watching 1080P AVC and HEVC content streamed over the network using Ethernet with no issues, no drop of frames just smooth playback.

I've watched some youtube content using Palemoon x64 and while page rendering wasn't great, the video playback was fine. Same result when using Edge browser.

And I've tested bluray and DVD disc playback using an external bluray drive, everything here works well.

The CPU runs at 1.5-1.6ghz the whole time.

I would imagine that the plywood case be better as far as venting heat, but it shouldn't be much different than the acrylic.

(Also a note, the metal shields simply clip in and can be removed and replaced pretty easily, if anyone has small enough heatsinks like those often used on the RPi they may work better.....but would need to be tested).

Re: CPU temperature high

Posted: Mon May 16, 2016 6:46 am
by ermingut

Hi. We doesn't have electric plan of LattePanda so this is only speculation...

You can not use Arduino outputs directly for fan (as you say they are limited to 40mA per channel but also ATMEL CPU has overall current limit) but I think is safe to use 5V outputs that are right of Arduino white connectors. They are probably connected directly on USB power source. I will check this with ohm meter later on.

Re: CPU temperature high

Posted: Tue May 17, 2016 1:32 am
I have a usb to 3pin fan connector and used a 120mm fan, I then used a fan grill to raise the fan a little and sat the LP on top of it (so air is blown in to the bottom vents onto the metal covering the CPU).

Temperatures are down to:


It reaches 73-75-71-74 while playing 1080P AVC content, which is a little better than before.

Re: CPU temperature high

Posted: Tue May 17, 2016 4:07 pm
by aodxxl
I am curently experimenting with adding a heatsink to it because it is unusable without one.
1080p videos drop frames , 1080p 60 fps are at 2 fps .
With active cooling ,4k 30 fps playback works flawlessly and the system feels snappy

Btw the procesor is on the underside of the latte , There is a thermal pad between the shield and the procesor so adding a heatsink will definetly help.

Curently experimenting with laptop blower style fans hooked to the latte panda's 5v connector ( the ones that look like cpu fan headers) Sucks that i dont have PMW control and the fan just spins at max speed

Re: CPU temperature high

Posted: Wed May 18, 2016 11:46 am
Let us know how it goes.

Re: CPU temperature high

Posted: Wed May 18, 2016 11:54 am
I'm not sure why yours would be unusable without extra cooling unless you have a very high ambient temperature (minimum 30+).

I has had no slow downs at all, unless I use a crappy power adaptor that is.

I'm only concerned with the temperature because we do get very hot i'm not sure if i'll be able to use it then.

But for now it's fine without extra cooling, though I am using a 120mm fan underneath (powered via usb so it's slow and silent) and a small usb desk fan to blow air in the side....because I get very nervous when my devices get too hot....I opened my router to add extra heatsinks and almost half the cpu temps lol.

Idle @ 34, max @ 75.

LattePanda cooling mod

Posted: Wed May 18, 2016 9:58 pm

Managed to get the cpu to drop by 10 / 15c see vid above