Asus RT-N66U - USB power

[szimat]

I am runnig John's fork on my router.
I have an Orange Pi Zero running as Pihole. I tried to power the OPi Zero from the router's USB port. It seams that everything is working fine, but I'm a little concerned not to damage the router. I think it should be easely power the OPi Zero, but could you confirm I wont damage anything?

Is there a way to test and see the USB current drawn and the temps, power consumption in the router gui?

Thanks!

 

[Grisu]

Should be ok as long as you dont connect anything on Pi's ports nor WiFi and LAN.
Here they tested it max 350mA and average unter 200mA should be fine for router USB port.
https://time4ee.com/articles.php?article_id=37

 

[szimat]

Should be ok as long as you dont connect anything on Pi's ports nor WiFi and LAN.
Here they tested it max 350mA and average unter 200mA should be fine for router USB port.
https://time4ee.com/articles.php?article_id=37

Well, I have LAN connected as it is functioning as a Pihole. Nothing to USB. USB port and WiFi is turned off on OPi Zero, and I have also decreased the Mhz to 960 Mhz, so it uses way less power and produces less heat. It is in OnDemand mode, and there is little stress on the device beeing only a Pihole.

I think it should not draw too much power. As of now, both the router and the Orange Pi Zero are working fine.
I think it is less than a 2.5" HDD would drain power.

 

[Grisu]

I think it is less than a 2.5" HDD would drain power.

Thats for sure, HDD will go up to 1A while turning on and about 500mA during read/write.

 

[szimat]

Thats for sure, HDD will go up to 1A while turning on and about 500mA during read/write.

So it should be safe to do, not risking damaging my router or the router's psu?

 

[Grisu]

yes

 

[sfx2000]

I have an Orange Pi Zero running as Pihole. I tried to power the OPi Zero from the router's USB port. It seams that everything is working fine, but I'm a little concerned not to damage the router. I think it should be easely power the OPi Zero, but could you confirm I wont damage anything?

Can't say anything about Opi Zero... depends on voltage/current demand there, other that it's an AllWinner H2/H3/H5 chip, and they can pull a fair amount of current - recommendations there is 5VDC/2A, which might be more than the USB2 port can provide.

You likely won't damage the router, but you might run into filesystem corruption on the Opi Zero if power browns out.

From the RPi folks - speaking for RPi Zero, they do not recommend this.

 

[Grisu]

Those 2A are needed if you plug in devices (HDD) to the USB ports of your Pi, but he runs it without any.
Same like your PC, you may have 700W power supply, but 200W would be enough without grahpic card and some other power hungry devices.

You are correct that it is not a recommeded usage to supply a Pi through its USB due to its internal circuit, but it can be done on your own risc, wont damage the master.
OP should know this when running a Pi - thats general knowledge for Pi-users.

 

[Val D.]

I think it should be easely power the OPi Zero, but could you confirm I wont damage anything?

RT-N66U runs hot. More power draw means more heat generation. Your router's power supply adapter will heat-up more also. Router's USB ports are communication ports, not designed to be power supply ports. Better power the Pi from a separate power source. You won't damage anything in a short run (Orange Pi Zero draws up to 300mA, as per tests on Internet), but why to put more strain on the router's power circuit?

 

[Grisu]

Do you know what you are talking about?
Heat comes mostly from CPU and little from WiFi chips - not from 5V power-regulator.
Pi as I showed uses under 200mA@5V, thats <1W for the power adapter and not worth to mention as it is about 6-8% difference on total power and designed for (USB2.0 @ 500mA).

For the router it's exactly the same how these 200mA are used, for a "communication" device (stick, HDD) or to power the Pi.

 

[Val D.]

Do you know what you are talking about?

I do very well. I used to repair N66U/AC66U routers and I know exactly what I'm talking about.

The way RT-N(AC)66U are designed in not optimal and the heat gets transferred to USB ports area, just next to USB voltage regulator. This is why the USB ports on those routers are always hot. OP may touch the USB ports area to find out for himself. More current through the USB voltage regulator means more heat in this area.

Pi as I showed uses under 200mA@5V

If you read carefully the link you provided, you may find the following:

"Peak consumption of current was 315 mA during the booting."
"Of course, if you connect OPi Zero to WiFi or Ethernet, the current will be increase."

That Orange Pi Zero has to boot at some point, you know. And this point of time is exactly when the router itself boots and has the highest power consumption. Therefore powering the Pi from the routers USB port is possible as a short term solution, but not recommended in a long run. OP is the one to decide what to do based on information provided. It's his own router after all.

 

[Grisu]

Confirmed that they all have very bad passive cooling, but same is true for any HDD on the USB port which needs upto 900mA while powering up on restart!
Problems are with USB-stick plugged in directly to the port getting to hot for permanent usage.
HDD and Pi are connectd with cable and dont suffer from heat of the router inside.

 

[Val D.]

but same is true for any HDD on the USB port which needs upto 900mA while powering up on restart!

This is why it's also not recommended to power an external HDD via routers USB port.

HDD and Pi are connectd with cable and dont suffer from heat of the router inside.

In this case the extra heat is damaging the router, not the device attached to it. USB power regulator is inside the router.

 

[RMerlin]

The way RT-N(AC)66U are designed in not optimal and the heat gets transferred to USB ports area, just next to USB voltage regulator. This is why the USB ports on those routers are always hot. OP may touch the USB ports area to find out for himself. More current through the USB voltage regulator means more heat in this area.

I recommend using a short USB extension to reduce heat issues with USB devices. I had a similar issue with my WDTV Live, where the USB disk was getting very hot because it acted as a heatsink for the WDTV Live. A 3 cm long extension resolved the issue.

 

[Val D.]

A 3 cm long extension resolved the issue.

Yes, in order to protect the device from the router generated heat. In this case though, more current going through router's voltage regulators equals more heat added to the router itself, and this router already runs hot even when doing nothing. My media bridge RT-AC66U runs at about 60C with less than 5% CPU load. USB ports area is skin burning hot. I know the CPU can handle higher operating temperatures, but I would not make things worse by powering an external device off this router. I've seen quite a few heat damaged RT-N(AC)66U routers. There are two electrolytic capacitors right next to the power switch and the USB ports, voltage regulators are at the back of the PCB, under the metal screen with no air circulation whatsoever. The original design was with a cooling fan, but ASUS changed it to passive cooling in production model. I have no idea how routers like this operate in tropical countries with 35-40C ambient temperature, for example. That aluminium passive radiator inside must be heating up to above 70-80C.

 

[dosborne]

Is there a way to test and see the USB current drawn

You can grab one of those handy little USB devices with a display that shows voltage/current usage. It isn't perfect, but would at least give you an idea.

I tried running a RPiZW in a similar way and I assume the "orange" clone is similar, but was not happy with the heat dissipation.

As rmerlin points out you could get a usb extension, but then again, why not get a dedicated power supply as they are only $8-$10? Then you don't have to wonder / worry.

 

[sfx2000]

I tried running a RPiZW in a similar way and I assume the "orange" clone is similar, but was not happy with the heat dissipation.

The AllWinner's run warm, more so than RPi Zero W - which actually would be the better of the two, IMHO

Orange Pi Zero - lots of stories about thermals and power, and the XR819 is a a bit of a challenge. Armbian is a good choice, as the H2/H3/H5 are very well sorted out.

I don't see it as a risk to the router - it should be good for 2A - I'd be more worried about the single board computer.

 

[Val D.]

I don't see it as a risk to the router - it should be good for 2A

USB2.0 ports trigger overload protection >0.5A

 

[sfx2000]

USB2.0 ports trigger overload protection >0.5A

If that's the case - then Orange Pi Zero would not be a good choice - Raspberry Pi Zero would be ok

 

[Val D.]

Raspberry Pi Zero would be ok

Must be Pi Zero W and the Pi Hole DNS server goes through WiFi. It works, but wired works better. This is why OP is using Orange Pi Zero, it has a LAN port. But still, use of a separate 2A power supply is preferred to power the Pi.