$9 Router Cooling (RT-AC68U Example)

[Rubenel]

https://www.law.cornell.edu/cfr/text/16/700.10

In California, and a couple of other states, you have additional protections.

...

Bookmarked the link. Thanks. [emoji1303]


Sent from my iPhone using Tapatalk Pro

 

[Magnus33]

Stumbled across this because we are presently pushing a major amount of data through are 68u and its going over 100.

As mentioned the max is 124 or 125 for the chip and the chip is likely going to perfectly fine without active cooling as mentioned.
But this fails to take into account the other parts of the router which are less happy with heat.

A perfect example is the fact we live in the land of lead free solder which really doesn't like heat much compared to the solder that had lead in it.
Lead solder was more malleable and tended not to develop cracks when exposed to repeated heating /cooling.
There was a wave of home receiver not long ago that had HDMI failures due to the solder balls not being able to deal with this issue.

If you can strap a fan on without voiding the warranty and run much cooler the device is quite likely to last longer.
If your worried about dust stick a filter in front of it.

Now all that said routers due to tend to last longer then support these days so you may end up having to upgrade before it dies.
With Asus/Merlin's amazing support though giving your router a little extra cooling certainly can't hurt since these routers are supported long past others in many cases.

 

[RypeDub]

As a summary on the drama in this thread:

Some users want to see low tempatures on their routers.

These users just simply don't understand how temperature effects these specific types of chips.

Just because the chips are called CPU's doesn't mean inside a router is similar to a computer CPU.

Rememebr all these fancy phones we have? They have CPU's too, with no fans.

Some electronics also function better with a little bit of heat.

On top of that, we are speaking in Celsius, 125 c is the max operating temperature, 24 hours a day, 7 days a week, for a maximum of 2 years.

So if we are operating at 80c or 60c or 50c, then we are going to obtain close to a decade or more of life span because it is exponential like that.

Someone mentioned lead free solder, that melts at over 180c, well above the max operating temperature, with the router shutting down when the TJMax of 125.3c is reached. You don't need to worry about that. This isn't the Xbox 360.

Now, back to the purpose of this thread:

It does not matter "why" we are doing this.

It only matters that we "can" do it.

I do NOT suggest tapping into your routers power supply or soldering directly or splicing using existing wires inside the router.

Use a USB plug and a pentometer to plug your fans into the USB ports as they provide 5v 1.5amp of power, which is more than enough to power 2x fans at acceptable RPM, noise or pressure.

As for the dust build up: use a hot glue gun to seal the fan to the back of the router and a dust filter as others have demonstrated in this topic.

Disassembling the unit is not that trivial so just check it every 6 months to a year.

Do not point the fans on the top of the router. You're wasting power by blowing onto hot pastic from the top cover. Have your fans blowing into the router from the back, through the vents.

I think I touched on all the points.

Lastly, these chips functional most optimally between 55c and 87c in my own personal testing. Below and above 55c simply lowers the signal output between 1-7db which is nominal anyways due to lots of other sources of radio activity, I do not own a lab to do more through testing.

But again, if we can do this mod: then do it lol it won't hurt, it may help some and otherwise it looks badass.

 

[M@rco]

As a summary on the drama in this thread

I think you might have just single-handedly revived 'the drama'...

 

[RypeDub]

I think you might have just single-handedly revived 'the drama'...

#SocialMediaHype

Yeah it's all good.

I just wanted to put all the information in once place and simply explain the differences between all the ideas, opinions and methods, while delivering it with the most technical approach.

I'll simply respond to anything with direct links to information or copy n past of what I already said, if relevant.

I have no opinions, other than technical possibility.

What I can also say is that if I had an available fan to use, I have some old USB cables, just need a pentometer and I'll be doing this my self, using just zip ties and the cleaning every 6 months to a year approach.

I MIGHT hot glue gun the fans for a better seal cause my wife is a teacher and I just so happen to have access to the tools and materials required.

I'll be using zip ties to secure the fans. I'll be using 2 or 3 depending on how long they are to secure in both a horizontal and vertical strap, running along the center of each fan (I'll be using 2 most likely, if not then just 1) in a cross patter to minimize air flow disruption.

 

[mgttr]

#SocialMediaHype


What I can also say is that if I had an available fan to use, I have some old USB cables, just need a pentometer and I'll be doing this my self, using just zip ties and the cleaning every 6 months to a year approach.

This is the second post where you refer to a "pentometer". I can't find any information on what this might be. Are you perhaps referring to a "potentiometer"?

 

[RypeDub]

This is the second post where you refer to a "pentometer". I can't find any information on what this might be. Are you perhaps referring to a "potentiometer"?

The perils of Autocorrect not working when it should be working.

I don't know how to spell that, but obviously that is what we are referring to.

A variable resistor.

 

[mgttr]

The perils of Autocorrect not working when it should be working.

I don't know how to spell that, but obviously that is what we are referring to.

A variable resistor.

Thanks for clarifying that for me. I was afraid there was some new type of component that I had not heard of before! Assuming you use a 12V fan, the 5V power from the USB bus is already a significant reduction (in fact some 12V fans may not even start at 5V). Do you think a potentiometer is still needed to reduce the voltage to below 5V?

 

[loveleeyoungae]

As a summary on the drama in this thread:

It's interesting that I suddenly thought of this modding today and did a search and found this old thread, then I went to this last page and saw your comment posted today

I'd want to suck the air out, but it seems that more people used the fans to blow cool air into their routers? I wonder if there is big difference between these two methods, as I don't mind if the temperature wouldn't go down much, but I wouldn't want to blow dusts into my router?

 

[Grisu]

I'd want to suck the air out, but it seems that more people used the fans to blow cool air into their routers? I wonder if there is big difference between these two methods, as I don't mind if the temperature wouldn't go down much, but I wouldn't want to blow dusts into my router?

I think blowing inside or outside with external fan wont make much difference, as in both cases on some points air must go in and in front of fan go outside or vice versa.

I want to put a very small 5V fan inside the housing to remove (or absorbe?) the heat from the cooling plates and bring faster to the cover where it will be radiated off.
So no dust will go inside as no air is blowing inside, not much more than with passive cooling. Ventilation stays almost inside the unit.
Of course little more air will ventilate through the housing slots too, but still slow enough not to carry in dust.
Placed behind the sticker would avoid direct air flow in or outside.
Opening is easy done but only after warranty as you will see it on the backside sticker which you have to remoove for unscrewing.
Only problem I dont know whether there will be enough space even for a very small fan.

I still didnt test this, but I'm quite sure it would reduce temps 10-15° below 65°C, just the amount that gives us a bad feeling.
Mine is at 75°C at the moment (both 68U and 86U) no reason to do anything, but in summer it went up to 85°C and that is definitely more than I want to see on my routers.

Maybe this one for Pi could fit 30x30x7 @5V/100mA: https://www.amazon.com/dp/B076H3FQ1W/?tag=snbforums-20

Just made first tests on my RT-AC68U:
1.) I removed the top metal shielding, thought air flow would be much better without (then making larger holes if it would work).
But no change at all, maybe 1°C lower, just to forget it.

2.) I removed the cooling plate completely
2G and 5G temps gone down by >5°C, so much better for them just without the cooling plate.
But CPU temp went up from 75 to 84°C. For CPU its worse.
Seems the heat is going from CPU to WiFi-chips as it will be spread over to them.

3.) now I removed the pads and instead put in quite thick cheap white standard electronic thermal grease. It is neccessary to use a lot (usually you use only a thin film) as the 2 metal shielding covers above the chips are not exactly same highness and the cooling plate is not plain as well. In a first step I tried to straighten it a bit as it was more bent than it should be.
Especially where the chips are (under the previous thermal pads) I put a lot of grease (~1mm).
Result: only 1-2°C decrease, so not really a good solution too.

4.) THINK I GOT IT !!!
RT-AC68U ALL chips lowered by ~10°C with small inside fan
2.4 GHz: 47°C - 5 GHz: 48°C - CPU: 66°C
before: 2.4 GHz: 52°C - 5 GHz: 54°C - CPU: 76°C (both measured after 90 min. uptime)

This time I used a 40x40x10mm 5V fan (had one at home) inside the housing.
I is a little bit too thick for placing behind the cooling plate.
So I decided to put it on frontside ontop of PCB near CPU.
Soldered directly on the outer pins of USB2.0 (+5V and GND).
Now my temps are solid (2 hours) where I want them, below 70°C CPU and WiFi even under 50°C.
As there are no holes or slots in front air ventilation can only be done inside the housing and no dust can get in (not more than with passive cooling).
The one I got is very loud, so I may buy a Raspi fan 30x30x7mm 5V@0,2A for 1,69€ free shipping and replace mine:
https://www.amazon.com/dp/B00UWIB68U/?tag=snbforums-20
Probably I will connect it to 3.3V@~0,12A instead of 5V to be almost silent.
For that I would use the outer pins of the 4 horizontal pins between the top left screw and the serial-sticker on the picture.
Maybe I will put it on backside in the middle between sticker and cooling plate, shoud be space enough for only 7mm thickness. There wont be much air ventilation to outside, as there are no slots too (sticker behind) and possibly even better cooling, lets see.

For long time usage it will be definitely better to use this one and place it behind frontside, only 50mA and 150000 hours MTTF instead of cheap with only 25000: https://noctua.at/en/nf-a4x10-5v?___from_store=de
In final solution fixed with hot glue and few mm space to PCB.

Next time I will have a look how to improve my 86U, but still in warranty, so maybe in winter.

Now I am happy and it can stay as it is for the rest of my and its life ...

My FINAL SOLUTION: (updated picture)
Bought this very durable and quite silent running low power fan Noctua NF-A4x10 5V 40mm 5 Volt@50mA: https://noctua.at/en/nf-a4x10-5v?___from_store=de
I bought in a local store even cheaper: https://www.amazon.com/dp/B00NEMGCIA/?tag=snbforums-20
One of the best you can get and fair price for 11€.
No need to mount it anywhere as there are 4 flexible holders which give space on both sides for air (not pulled in completely so they stand out about 5mm on top side and bent to the side on print).
Just layed in place like on picture and put on cover. Luckily holds very well in position due to this flexible holders without anything else.
There is a 2 pin adapter inside, so easy to (dis)connect if needed.
The low current of only 50mA will not effect USB in any way.
Could even be connected without any soldering on outer 2 pins of 4 pin jumper for serial connection on backside but then only running slower with 3,3V.
I used this 3,3V instead of 5V shown on picture.

Advantages:
-11°C on CPU (OC from 800 to 1200MHz before Current Temperatures: 51 °C - 53 °C - 76 °C -> after Current Temperatures: 47 °C - 50 °C - 65 °C
NO dust gets in
nothing to hear
very low power consumtion 50mA/5V from USB2.0
not visible

Drawback: Need to open case and solder 2 pins (done in 10min)

Here you can see the cooling down while opening and connecting the fan and closing again.

 

[loveleeyoungae]

I want to put a very small 5V fan inside the housing to remove (or absorbe?) the heat from the cooling plates and bring faster to the cover where it will be radiated off.
So no dust will go inside as no air is blowing inside, not much more than with passive cooling. Ventilation stays almost inside the unit.
Of course little more air will ventilate through the housing slots too, but still slow enough not to carry in dust.
Placed behind the sticker would avoid direct air flow in or outside.
Opening is easy done but only after warranty as you will see it on the backside sticker which you have to remoove for unscrewing.
Only problem I dont know whether there will be enough space even for a very small fan.

I still didnt test this, but I'm quite sure it would reduce temps 10-15° below 65°C, just the amount that gives us a bad feeling.
Mine is at 75°C at the moment (both 68U and 86U) no reason to do anything, but in summer it went up to 85°C and that is definitely more than I want to see on my routers

I live in a country with a bit hot weather (28-38°C) and my city is a bit polluted, hence the desire of cooling the router without blowing dust into it. I actually oc'ed the router and currently only OpenVPN is enabled, and the CPU temp is 81-84°C. Don't know if I should revert the OC, as before oc'ing the CPU temp was 72-76°C.
Thought of laptop cooler pads as a good one is quite cheap here (3-9 USD), but they all blow the air in (obviously laptops have different type of ventilation where they have fans at bottom to suck air into the laptops). Well, maybe I'll have to do the modding.

 

[RypeDub]

I'd want to suck the air out, but it seems that more people used the fans to blow cool air into their routers? I wonder if there is big difference between these two methods, as I don't mind if the temperature wouldn't go down much, but I wouldn't want to blow dusts into my router?

You could point the fan the other way and seal it to the back, then e seal all other holes in the back and make a new one in the front.

That would cause some nice pressure and you could achieve your method of sucking the air out.

You could also do a push pull for extra effectiveness.

I think for the small enclosure, any method will be within margin of eachother.

 

[Grisu]

I live in a country with a bit hot weather (28-38°C) and my city is a bit polluted, hence the desire of cooling the router without blowing dust into it. I actually oc'ed the router and currently only OpenVPN is enabled, and the CPU temp is 81-84°C. Don't know if I should revert the OC, as before oc'ing the CPU temp was 72-76°C.
Thought of laptop cooler pads as a good one is quite cheap here (3-9 USD), but they all blow the air in (obviously laptops have different type of ventilation where they have fans at bottom to suck air into the laptops). Well, maybe I'll have to do the modding.

Have OC mine too from 800 to 1200 MHz, raised the temp 5°C from 71 to 76°C at no load.
At the moment testing a little fan inside 40x40x10mm 5V I had at home.
But as there is not enough space on backside for this so I placed it in frontside near CPU.
Sure here will be no air ventilation from outside to inside and no dust as there are no holes. Soldered on USB 5v pins. Looks good, must wait 1 hour for telling results.
A smaller 30x30x7mm 5V for Raspi will be possible on backside too.

HAVE a look at my previous post (updated my tests with good results), maybe the best solution for you too ...

 

[loveleeyoungae]

Have OC mine too from 800 to 1200 MHz, raised the temp 5°C from 71 to 76°C at no load.
At the moment testing a little fan inside 40x40x10mm 5V I had at home.
But as there is not enough space on backside for this so I placed it in frontside near CPU.
Sure here will be no air ventilation from outside to inside and no dust as there are no wholes. Soldered on USB 5v pins. Looks good, must wait 1 hour for telling results.
A smaller 30x30x7mm 5V for Raspi will be possible on backside too.

HAVE a look at my previous post, maybe the best solution for you too ...

That's nice. I think I'll try on the router that is now out of warranty Thanks.

 

[Pila]

How about some comparison? I have different models, but they are actually mostly the same. Nothing is overclocked and switches do the heavy lifting, so routers load is very light.

Asus RT-AC68U is the hottest one. At the summer, its proc is over 80C. Works normally after 3 years.

Asus RT-AC56U is the same hardware, but this model is constatnly 2C cooler. Both are vertical.

Now compare the RT-AC66U_B1: almost the same hardware but 3 years newer hardware. At this moment, my Asus RT-AC68U proc is 74C while my RT-AC66U_B1 is 65C! Typically, B1 is 10C colder!

 

[loveleeyoungae]

How about some comparison? I have different models, but they are actually mostly the same.

4.) THINK I GOT IT !!!
RT-AC68U ALL chips lowered by ~10°C with small inside fan
2.4 GHz: 47°C - 5 GHz: 48°C - CPU: 66°C
before: 2.4 GHz: 52°C - 5 GHz: 54°C - CPU: 76°C (both measured after 90 min. uptime)

I was a bit lazy, so after seeing an ad for this fan (yeah thanks to our dear spy Google), I just went out and bought it. Never had experience with these little fans, at first I thought it was weak when testing at the shop. But it did amaze me as it helped drive the CPU temperature from 87°C down to 66°C

Nice things about it:
- its 4-leg bottom part/pad (sorry for my English) can be unscrewed and re-positioned in the front. I.e. you can make it blow air into or suck air out as you wish
- the 4-leg bottom part hangs on the router easily without any modding
- as you can see in the photos, its size is fit and especially suitable for AC68U so that I can plug in, plug out cables and USB stick without any difficulty.

Actually I like it so much that I bought another one for the other router A bit pricey here though (8.5 USD), originated from China (look like they have the 2-fan set as well).

But yeah, these little fans do work!

 

[OMNI619]

Do it get very hot? I like the fan

Sent from my SAMSUNG-SM-G920AZ using Tapatalk

 

[loveleeyoungae]

Do it get very hot? I like the fan

Sent from my SAMSUNG-SM-G920AZ using Tapatalk

Why would you think it get hot? Didn't you read our posts, we all told that those fans reduce the temperature significantly!

 

[sfortis]

summer just arrived, router is going hot again! cpu was 95+ and throttling was obvious causing 1 core temporary decommissioning.

another quick, non-destructuve fan mod brought temps down to safe level

 

[martinr]

summer just arrived, router is going hot again! cpu was 95+ and throttling was obvious causing 1 core temporary decommissioning.

another quick, non-destructuve fan mod brought temps down to safe level

Looking to see where you live, because it can’t possibly be the UK if it’s warm outside, I saw you were:

Viewing thread Overclocking RT-AC56U, 20 minutes ago

Have you been up to no good?