Router temperatures

[Hazel]

Not ALL the 12V Noctura fans will start up at 5V!!

For anyone facing the issue mentioned by @gattaca , and willing to spent a bit more, I can highly recommend the Noctua NFP12-Redux 1300 120mm fan with a Noctua NA-FC1 PWM Fan controller with a no-stop safety feature. I'm using an external power supply, as I've been recommended in the past not to use the routers USB as a power supply, if I recall correctly because it might cause interference. Regardless which (4-pins) 12V fan your using, this fan controller makes sure that you 12V Fan stays running and doesn't stop when lowering the voltage your feeding it, and allows you to find the perfect balance between a low sound level and acceptable temperature levels.

Mine is set just below 50% (which should be around 5V) of maximum speed (=12V/1300RPM) and with an ambient temperature of around 24 degrees Celcius my CPU temp, my current CPU temp hovers around 56~57 degrees Celsius which is more than acceptable to me. And I can't hear the fan, unless the room is completely silent and I keep my ear near my router.

Once every few weeks I set the fan controller to max for a few minutes (with the router powered off) to blow the dust out and use a rechargeable vacuum cleaner to clean the back of the router for the collected dust around the fan. See one of my previous posts for additional details and some pics if you're interested. I truly believe it has worth the extra money, as I'm now able to control the temperature of the internal components of my router to 1 or 2 degrees Celcius accuracy, which I wasn't before and I'm convinced this will prolong the lifespan of my RT-AC86U.

 

[gattaca]

^^^ MT3125 - WOW!! + to the department of "strange coincidence" - + my 2.2 year old RT-AC86U, which I just replaced with an RT-AX86U, to the dead units. I had flashed it back to stock, reset to factory defaults and tested it. As I was preparing to box it up, I'd forgot to take photos so I powered up. When I flipped the power switch, something inside went "poof" and it was "game over". LED4 barely lit and it would not boot. I'm guessing this inductor died. That's just bad marginal design! The unit has been working fine for 2.5 years and was cooled with a fan per above. I can only hope my other AC86U units hold. GROWL!

 

[slo-nic]

 

[gattaca]

^^^ @taffeys + to per above @Hazel , WRT which 12V Noctura I have tested to spin up at 5V?

This is another related post -> https://www.snbforums.com/threads/router-temperatures.71123/page-7#post-673557

a) 1 x Noctua NF-P12-redux-1300 (or 900) 120mm/12V fan (~$14 USD)
b) 1 x Noctua NF-P12 FLX (may be discoed but has the UNLA/LNA + vibration corners etc.. ) (~$20 USD)
c) 1 x NF-S12A FLX (~$20 USD)
d) Do NOT confuse above with the NF-S12A ULN. I tested the ULN model and it would NOT spin up at 5V!
e) Every 12V model I have with the NF-Pxx FLX I've tested (3-4) has spun up at 5V.

f) FWIW, this is the best tiny, low electrical nose, 12V Fan PSU I've found to date if you want an independent PSU. I do not have any data on the longevity/MTBF. -> CoolerGuys 12VDC tiny fan PSU

g) This is the USB to 2 pin fan cable if you want to go that route -> 5V USB to 2 Pin Fan Cable(s) (Amazon)

h) @Hazel solution using the Noctua PWM controller is very good too. I had quite a few Noctua non-PWM 120MM fans in my "project box" from other work, so I just never went there. Stay safe, stay alive. Peace.

 

[slo-nic]

 

[slo-nic]

 

[Tech9]

I'm guessing this inductor died.

The chip died, most likely. It's a common thing with AC86U. Some places contain pages long discussions about this issue. The power converter is reference design and should be able to provide up to 6A output. Something else behind it goes bad and causes the chip to burn instantly. Here is the datasheet, if you want to look at it - https://www.m3tekic.com/upload/2016/01/20160121155909.pdf

 

[Patrick9876]

Thanks for starting this thread and thanks to the many folks who have commented with helpful insight, ideas, and thoughts.

In the hopes that more observations will be helpful, I wanted to share temperatures from my RT-AC86U before and after adding a cheap external fan I purchased from amazon: https://www.amazon.com/gp/product/B07XDGXWC3/?tag=snbforums-20

My biggest concern in purchasing this fan was that it would be too loud. The unit I bought has a knob that adjusts the fan speed. I currently have it at about the 50% mark and the noise is barely perceptible. Based on the 15-20°C reduction in CPU temps I've seen, I have been very happy with the results.

384.19 temps 51 57 72 °C
386.1_2 temps 52 57 77 °C (no fan)
386.1_2 temps 45 52 59 °C (with fan)

*Edit to add that I am using 3 of the 4 available LAN ports.

View attachment 32033

I just bought and attached one of these and got very similar results - also running the fan at half speed or less. I notice one very big potential problem, though. The fan completely blocks the back vents. If the fan dies or the filters get clogged with dust there will be no passive cooling and we'll be worse off than if we just used the router's original cooling.

 

[gattaca]

^^^ 10-4 That's one reason I suggested "higher quality" fans like Noctura with magnetic bearings and MTBF at 150,000 hours vs no-name $2.00 sleeve-based fans that might get 20K hours. The router will throttle itself in general if it get's too hot. Chips tend to shutdown at their design limits of 105C - so while you may not see flashing alarms, you will start having problems in performance and stability. I set a calendar notice for every 4-6 months to clean the routers.... takes 10 mins and if they are not that dirty, I might move it to 6 months. YMMV. Stay safe, stay alive. Peace.

 

[Patrick9876]

^^^ 10-4 That's one reason I suggested "higher quality" fans like Noctura with magnetic bearings and MTBF at 150,000 hours vs no-name $2.00 sleeve-based fans that might get 20K hours. The router will throttle itself in general if it get's too hot. Chips tend to shutdown at their design limits of 105C - so while you may not see flashing alarms, you will start having problems in performance and stability. I set a calendar notice for every 4-6 months to clean the routers.... takes 10 mins and if they are not that dirty, I might move it to 6 months. YMMV. Stay safe, stay alive. Peace.

I've followed your advice (although not your design) and purchased a Noctua NF-P12 redux. a Noctua fan controller, and a 12v power supply. I also bought a dust filer, but the plasticizer in the filer has an intense obnoxious smell that quickly spread though several rooms. (I now have the fan sucking air through a piece of cheesecloth.)

I did not follow your design (shown here) because the fan blocks the router's passive cooling. If the fan fails for any reaon the router overheats. Instead, I've got my fan positioned about 2 inches (9 cm) behind the router. It doesn't provide as much cooling as your config, but I'm running at a pretty constant 45 °C - 53 °C - 60 °C (2.4 GHz, 5 GHz, CPU) so I'm satisfied.

 

[explorer200]

I never even thought to check the temp of my router CPU but it's 23°C here and the CPU in my AC86U is running at 98°C. This is an insane temp. How is this ok?

 

[Morris]

I never even thought to check the temp of my router CPU but it's 23°C here and the CPU in my AC86U is running at 98°C. This is an insane temp. How is this ok?

That is hot. Check the log for throttling. Add a small fan. I powered a 120mm computer case via the us be port and mine cooled down. It will run about half speed and be near silent

 

[Clark Griswald]

I typically have 78C-83C (cpu) on my AC86. My main router is located on a shelf (approx 78" high) in my network closet. Today, I placed This Fan on the same shelf (not plugged into router) and the results w/ fan on low:

All this discussion about opening the router etc, I follow the KISC Method
(Keep It Simple Clark)

 

[Andrew LB]

Print this up and you're good to go. Fast, easy, and simple.

ASUS AC88U Fan by andrea70

Just a fan for Asus AC88U

www.thingiverse.com

 

[heysoundude]

Print this up and you're good to go. Fast, easy, and simple.

View attachment 34756

ASUS AC88U Fan by andrea70

Just a fan for Asus AC88U

www.thingiverse.com

You, sir - I want something similar for the bottom vents on the back of my AC86 - did you design that? what do you need in terms of measurements from me for mine?

 

[Clark Griswald]

@Andrew LB Nice Work
I can't convince The Wife we "need" to upgrade to an AX86, so I can't imagine this scenario will work:
"Honey, I need a 3D printer, it's for the router"

Edit: My Fan is still keeping temps 54C approx

 

[Cr00zng]

For anyone facing the issue mentioned by @gattaca , and willing to spent a bit more, I can highly recommend the Noctua NFP12-Redux 1300 120mm fan with a Noctua NA-FC1 PWM Fan controller with a no-stop safety feature. I'm using an external power supply, as I've been recommended in the past not to use the routers USB as a power supply, if I recall correctly because it might cause interference. Regardless which (4-pins) 12V fan your using, this fan controller makes sure that you 12V Fan stays running and doesn't stop when lowering the voltage your feeding it, and allows you to find the perfect balance between a low sound level and acceptable temperature levels.

Mine is set just below 50% (which should be around 5V) of maximum speed (=12V/1300RPM) and with an ambient temperature of around 24 degrees Celcius my CPU temp, my current CPU temp hovers around 56~57 degrees Celsius which is more than acceptable to me. And I can't hear the fan, unless the room is completely silent and I keep my ear near my router.

Once every few weeks I set the fan controller to max for a few minutes (with the router powered off) to blow the dust out and use a rechargeable vacuum cleaner to clean the back of the router for the collected dust around the fan. See one of my previous posts for additional details and some pics if you're interested. I truly believe it has worth the extra money, as I'm now able to control the temperature of the internal components of my router to 1 or 2 degrees Celcius accuracy, which I wasn't before and I'm convinced this will prolong the lifespan of my RT-AC86U.

On my AX-86U, I placed a single, 80mm, 5 VDC Noctua fan blowing in over the WiFi chips, connected to an older iPhone charger. The fan also has a Silver Stone dust filter; these are the router temperatures at ambient temperature of 21 °C (70 °F) and 65% relative humidity:

This solution isn't silent, but one would need to be close to it to notice...

 

[zdaw700]

If you're buying a Noctua fan and want to run 5vUSB just buy an "NF-F12 5V". It includes an adapter and in what I'm seeing (at least locally) is the same price as a regular F12 minus the convoluted process of a separate PSU or hacked wall warts.

Really all ya need, just 1x 80mm fan on a router like the AC86U (~NF-A8 5v?). 120mm isn't efficient nor is 2x80mm for the vents on this design. A little airflow goes a long way, but a lot does very little.

86U router is Pull configuration, and leaving ~15mm of space (mounted on fan "feet") sealed duct between fan shroud and router gives a quieter result (and TBH better temps), as pushing creates more noise.

Just single "AC Infinity" 80mm on it (able to use USB/Diversion and WiFi just fine, no interference), but the bearings are loud-ish and the quality is throwaway (got them before the 5v fans were reasonably available, cost wise, on Amazon).

Temps are 35~55°C depending on room, even during summer.

 

[Ryansr]

Wow, these temps are just insanely high for just a wifi router and not a dsl - wifi router combination! Anyway I think this is ASUS trying to nudge people into upgrading to one of their WiFi 6 routers (almost like MS is doing with Windows 11).

 

[DirtyFlash]

Alright, I posted a couple months back about trying a 40mmx40mm USB fan that I purchased for $1.50 on eBay. It was attached it to the back on the the left side above the vent slots with two-sided tape. It dropped the radio temperatures by 8C and the CPU by 12C. Being an inexpensive and simple affair, I thought I would acquire another one for the right side to see what the combined results would be. radio temperatures dropped a total of 10C and the CPU 25C. So for 3 bucks I'm quite pleased with the results. The fans emit no perceptible noise as they are very small.

Edit: After running the two fans yesterday. I thought I would do another test by not running the original fan on the left. It seems to not make much difference, other than the radios and CPU run about 2C higher. In conclusion, you can just use one fan on the right side vent slots for effective cooling. In case I failed to mention it, I'm using a AC1900P (AC68U).