Community discussions

MikroTik App
 
megaklutz
just joined
Topic Author
Posts: 2
Joined: Mon Aug 08, 2022 11:53 am

power adapter for mikrotik 951

Mon Aug 08, 2022 12:10 pm

Hi all.
I have connected ZTE 3g modem to the mikrotik 951ui-2hnd usb, but it randomly disconnects from the usb, then reconnects again, in general it does not work stably.
I read that new more powerful mikrotik power adapter will be solved. Can I connect mikrotic 24HPOW 24V 2.5A adapter to this router?
Or also I have the HP power supply with OUT parameters - 19V, 4.75A, 4.75A - is this not much for this router?
Thanks!
 
User avatar
BartoszP
Forum Guru
Forum Guru
Posts: 2393
Joined: Mon Jun 16, 2014 1:13 pm
Location: Poland

Re: power adapter for mikrotik 951

Mon Aug 08, 2022 6:56 pm

Seems to be safe to use oversized PSU. Voltage is proper in range.
Current is supplied on the device demand so if 951 needs 1A then PSU supplies 1A, if 2A then it supplies 2A. It does not push 4,75A to device all the time.
 
mkx
Forum Guru
Forum Guru
Posts: 8970
Joined: Thu Mar 03, 2016 10:23 pm

Re: power adapter for mikrotik 951

Wed Aug 10, 2022 1:04 am

My guess is that it's not PSU problem (whole RB951 would restart in this case), but rather RB951's USB port power limitation (when 3g modem tries to draw too high current, RB951 doesn't provide it causing 3g modem to reset). Wireless broadband USB sticks are notorious to draw much more than standardized 0.5A@5V (some USB hosts provide more than standard requirement, RB951Ui spec says 1A which might be enough for your 3g modem most of time).
This problem can often be solved by using a specially crafted USB Y-cable (connects single USB device to two USB ports, one of them is only providing power), but doesn't work on RB951 as it only provides single USB port. But: it is often possible to connect powered USB hub to RB (use of separate hub power source is mandatory) and then use the mentioned Y-cable to connect 3g modem to USB hub.
 
Valerio5000
Frequent Visitor
Frequent Visitor
Posts: 70
Joined: Fri Dec 06, 2013 2:38 am

Re: power adapter for mikrotik 951

Wed Aug 10, 2022 1:47 pm

In this 951 is runnig ROS 6 or 7 ?

ROS 7 for my 951 and USB 4G a fixed a recognition problem similar
 
megaklutz
just joined
Topic Author
Posts: 2
Joined: Mon Aug 08, 2022 11:53 am

Re: power adapter for mikrotik 951

Wed Aug 10, 2022 5:57 pm

OpenWRT, Unfortunately i need in OpenVPN TLS authentication.
Another question: I have POE-af deviсe with draw max 9Wt. If i connect this device to 5-port (Poe-out) - i must use 18V power adapter? Or Passive POE and POE-af is not compatible at all and need to use poe-converter?
 
mkx
Forum Guru
Forum Guru
Posts: 8970
Joined: Thu Mar 03, 2016 10:23 pm

Re: power adapter for mikrotik 951

Wed Aug 10, 2022 9:04 pm

By "POE-af" I guess you're referring to 802.3 af. Which is a completely different beast than Mikrotik's passive PoE. For starters it requires 48-57V while RB951Ui can go up to 30V. Then there's some inteligence built in 802.3 af going on between PSE and PD, with passive PoE not so much. So you'll have to use PoE injector for powering your device.

Who is online

Users browsing this forum: No registered users and 3 guests