Mini-UPS for simultaneous power supply of LTE-modem and ax86u

[koaly]

Hi guys,
I need to move the ax86u router together with its LTE-modem to another room, where there is no UPS-available. Power interruptions happen about every second month and I am used to protect all electronics.
I found and ordered such a mini-UPS with simultaneous connection of several devices from 5V to 12V. Here is also Amazon webpage.
I connected the router to 12V, and the modem to 5V. Oddly enough, but everything started. When I disconnect the UPS from the power outlet, everything keeps working. The temperatures in the router are the same as when using a original 19V power supply.
I know, the router comes with 19,5V/2,31A PSU, but why it works out of 12V/2A?

What can be affected by low supply voltage? What do you think? Is there something to be concerned?
I can potentially replace the UPS by a larger device with regular power sockets, but I'd avoid it for a sake of saving space.
Thanks in advance

 

[bbunge]

Would be much safer to use a line voltage UPS and the power supplies that came with the router and modem. Could be some warranty issues. Hide the UPS under a chair or table!

 

[koaly]

Would be much safer to use a line voltage UPS and the power supplies that came with the router and modem. Could be some warranty issues. Hide the UPS under a chair or table!

Thanks for the reply. I'll do so.

 

[beneix]

I found and ordered such a mini-UPS with simultaneous connection of several devices from 5V to 12V. Here is also Amazon webpage.

I have been looking to buy exactly this type of mini-UPS, and I had looked at this very item on Amazon but I was deterred by the number of reviews stating that routers like the Fritzbox cannot keep going when there is a power failure, because there seems to be a 2-3 second period when insufficient voltage is provided. Then there are some positive reviews contradicting this, so there might be some quality variances in production. Therefore it would be great to get some feedback from you after you have used it for a while.

 

[Tech9]

I know, the router comes with 19,5V/2,31A PSU, but why it works out of 12V/2A?

Because nothing inside uses 19V and the voltages are dropped down with VRM's. The router will work on 12V, but it may become unstable under load and even bricked during firmware update. Get a small UPS and plug the router/modem own power supplies there. It's still not ideal, because small UPS are usually cheaper square wave output devices, but it's better. The power supplies will heat up a bit more, but most work with no issues.

 

[koaly]

I have been looking to buy exactly this type of mini-UPS, and I had looked at this very item on Amazon but I was deterred by the number of reviews stating that routers like the Fritzbox cannot keep going when there is a power failure, because there seems to be a 2-3 second period when insufficient voltage is provided. Then there are some positive reviews contradicting this, so there might be some quality variances in production. Therefore it would be great to get some feedback from you after you have used it for a while.

I can confirm that my sample works well without any power interruptions. If I manually unplug it from the socket there is no any disruption or any sign of a problem both on a modem or router side. I ran speedtest.net during the unplugging. Worked well as nothing happened.
Probably Fritzbox is more sensitive, I cannot say, but Asus and Zyxel works well on it.
I will return it anyway as of low voltage issue.

 

[koaly]

Because nothing inside uses 19V and the voltages are dropped down with VRM's. The router will work on 12V, but it may become unstable under load and even bricked during firmware update. Get a small UPS and plug the router/modem own power supplies there. It's still not ideal, because small UPS are usually cheaper square wave output devices, but it's better. The power supplies will heat up a bit more, but most work with no issues.

Thanks for the clarification. Of course, I do not want to brick it. I will set a small and simple UPS without any "smart" functions. There are still no devices on the market, unfortunately, which would provide multiple DC outputs.
I personally find concept wrong to double convert power AC to DC (battery) and them again DC (battery) to AC and over PSU again to DC instead of having simpler AC-DC conversion in the UPS as all of electronics utilize only DC power.
Every conversion lead to losses and heat distribution. It would be a good "green" approach to avoid unnecessary conversions

 

[Tech9]

I personally find concept wrong to double convert power AC to DC

Much more power conversions happen. From about 1kV generator up to 14kV power plant output, up to 750kV power transfer lines, down to 4kV in transformer stations, down to 110V in local transformers, 110V to 19V and through VRM's inside the router to 9V, 5V, 3.3V and... you get Wi-Fi.

 

[koaly]

Much more power conversions happen. From about 1kV generator up to 14kV power plant output, up to 750kV power transfer lines, down to 4kV in transformer stations, down to 110V in local transformers, 110V to 19V and through VRM's inside the router to 9V, 5V, 3.3V and... you get Wi-Fi.

Agree. Nevertheless, the high-voltage converstions make sense, because there are less energy losses by the higher voltage wire transfer.
In our case multiple conversions in the circle between UPS and electronic devices is a waste, paid by us, end users. Of course it makes UPS more universal as some electronics have internal PSUs and you can use it for anything.
There is one more mini-UPS device with DC output from Eaton, but only one output 5-9-12-19V. It's a pity they did not implement multiple simultaneous outputs.

 

[Markfree]

My ISP modem is rated for 12v-2A and my Asus router for 19,5V-2,31A.
So, both devices add up to 69W of power requirements.

I found the mentioned mini-UPS quite interesting, but there's another option that has more power, FX 5-12 Pro.
To power 2 devices, I guess the latter is more appropriate.
Still, I'm not comfortable using it since it is not rated for 19v.

There seems to be other options available for 12v as well, but very few for 19v.
Eaton's mini-UPS seems nice but only rated for 36W, which is not enough to drive a 45W router.

Also, I did not find any mini UPS option with surge protection.

 

[josephclemente]

Asus lists 12V 3A (why not closer to 3.75A?) as a power supply on their web site here:
https://www.asus.com/us/Networking-IoT-Servers/WiFi-Routers/ASUS-Gaming-Routers/RT-AX86U/techspec/

I've only seen them ship with either the small square shaped 19.0V 2.37A or the larger rectangular 19.5V 2.31A power supplies.

I was searching for a good DC battery backup for a short while but didn't see anything that I felt I could trust for safety, specs and future battery replacement.