Hi y’all looking for advice here
I selfhost a nextcloud server and a NAS for backups, and one of my challenges has been data corruption after power failures.
I went and bought some consumer UPS units about 5 years ago, which helped, but now the batteries are starting to fail, and I’m not protected from power outages until I replace them.
I have the router on UPS as well so the computers can communicate with each other that the power has failed and it is time to gracefully shut down (using NUT).
However the router itself uses quite a bit of power and I am hoping to make a smarter decision this time around when getting a UPS.
The router’s power supply is 12V5A with a barrel style jack, so i have been searching for “DC UPS 12V 5A” to try and find something compatible that wastes less energy converting from battery DC to AC for the power supply to then convert back to DC.
But the only thing I’ve been able to find are these units designed to power electric doors: https://www.amazon.com/dp/B0D8VLPRN2/
I’m not sure if this would even be safe to use with a router, and i don’t know how i would wire it up to the router either.
I think i just don’t have enough knowledge to know how to shop for an appropriate DC UPS, or if such a thing even exists.
Anyone been in a similar situation?
Just replace the batteries in the ups. They are almost always standard lead acid batteries. Take a pic of the wiring, swap them out, and you’re good.
I went the POE route, inject poe to the router and use a POE to DC jack extractor to power the router/modem. My Poe injector is behind my UPS so it will remain powered on.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:
Fewer Letters More Letters PSU Power Supply Unit PoE Power over Ethernet SATA Serial AT Attachment interface for mass storage ZFS Solaris/Linux filesystem focusing on data integrity
4 acronyms in this thread; the most compressed thread commented on today has 10 acronyms.
[Thread #112 for this comm, first seen 25th Sep 2026, 15:20] [FAQ] [Full list] [Contact] [Source code]
Something about this doesn’t seem right. An ordinary router shouldn’t be the power hungry device that breaks your UPS setup. I have 3 Lenovo M910Qs, an HP T640, a switch, an external USB SATA drive housing, and two MODEM/routers hooked up to a cheap Cyberpower UPS and it tells me I’m drawing about 100W and should run for over an hour.
I did this once with a router. I just bought a 12V SLA battery (a UPS battery) and a car float charger (sometimes called a “battery maintainer”). The charger was always connected to the battery, so it was pumping about 13V into the router. The router could withstand it. It’s easy enough to get a voltage regulator if it’s an issue, but most hardware already does it to an extent. It was DC all the way.
If I want 5V, I get a car USB charger and stick it inline.
While there is DC power the battery in a UPS isn’t used. It’s not a constant AC-DC-AC conversion, that conversion only happens when there is a power outage.
The problem is that lead-acid batteries are a really shitty technology with high self discharge rates and short overall life span (their only advantage is high burst capacity that’s good for starting motors).
I would look for 12V LiFePO4 batteries in a standard lead-acid form factor that are meant as drop in replacements. Those are somewhat more expensive (like 2-3x the price) but will likely last a quarter century or more.
I am currently using an interim solution where my solar inverter has an seperate emergeny power outlet that works even when power is cut. Sadly it doesn’t switch to battery fast enough (like half a second delay 😓) for it to work as a UPS directly. But in combination with some old regular UPS that have spend batteries that only last a few minutes it works ok. But yeah, not the most efficient option conversion wise, but solar power is free 🤷
I did that and it works well. The only problem is that when the battery goes to 0 on a long outage, the UPS can’t recharge it. I had to pull the battery, charge it with a lifepo4 charger, then reinstall.
Short outages are fine.
Probably best to use NUT to shut down the servers gracefully if the power outage is too long.
The common solution is not to replace the UPS but only the battery inside. They are standard sizes and for a cheap UPS probably around 10 - 20 bucks.
This. My ups died after 10 years powering router and network. A replacement was $300 (for similar model) but the batteries were only $80. Just had to untape the pack and plastic adapter and transfer it over to the new battery set
THIS! Normally, the battery should be accessible via some door or a few screws. Replace the battery for a few bucks and you’ll have 5 more years of peace.
That rating from that PSU will be the max it can supply, it is very unlikely that a consumer router is pulling 5A.
Your router firmware might even expose its power consumption if you are lucky.
I have the same/similar setup. My wall-warts are just plugged into the UPS.
Yea, small business routers (think old Cisco boxes) use a 5A laptop-style power supply. I suspect this is what OP’s using, as I’ve never seen a consumer model with such power specs. Consumer stuff is built around the cheapest hardware they can get away with.
Thing is, I don’t doubt the Cisco box (or similar business units) may need that much juice at times. Put your hand over one that’s not connected but powered on and they get hot.
Stuff like that they really don’t care about power consumption during design, just capability.
I was just thinking the same thing. I was also thinking you can get a wide input voltage buck converter on amazon for cheap and use a bunch of cells in series as the UPS and the buck converter spits out 12V until it cant anymore. Then just wire up a charge controller to charge and balance your lead acid cells.
If you are using a buck converter you might as well use a ups. They’re both going to be ~ 95%.
I mean, there are 12V native battery systems out there, stuff like vehicle systems.
Assuming that the 12V power supply on the router is permissive enough to take a certain amount of variation, I imagine that you can probably just put a 12V deep-cycle battery on the thing on the thing and directly hook up a 12V charge controller in parallel.
I dunno whether there’s some sort of voltmeter that you can connect NUT up to.
Personally, my position is that if NextCloud or whatever can’t handle power loss without corrupting data, that’s a bug with NextCloud. I mean, sure, it might not be able to complete an operation if there’s power loss while it’s running, but that shouldn’t result in corrupt data.
What’s the underlying filesystem on a nextcloud server? ZFS? Or something else.
Search for “router UPS”
For example there is one from APC “# APC Back-UPS Connect 12V DC 36W - CP12036LI”
If you search for “12V ups” there are several. However, most only go up to 2 Amps. Not sure what kind of monster router actually needs 5 Amps, though. Also, I believe those 12V UPSes don’t provide status information via USB. So, there’s no way to know when the battery backup is going to fail.
How about a portable power station? Basically a huge mobile battery with AC input. Some can switch over on power failure like a UPS. Some has USB PD (get 12V DC with the right cable) or car lighter socket (12V DC) or direct 12V DC output.
I’m talking about these, just a random article from my search:
If you’re going this route, you may want to pay attention to the switchover time. For most consumer hardware, it can handle 10-20ms of switchover time. However, enterprise grade stuff is more sensitive to power fluctuations and sometimes needs near instantaneous switchover. It can get very expensive if you want LiFePo4 (like many of these portable stations) while also being “on line” (meaning instant switchover).
There are middle ground options which have switchover timing of 5-8ms that are also LiFePo4. LiFePo4 is great because the chemistry doesn’t have a huge fire risk and it can do more cycles than a lead acid battery.
Anyway, my bad for rambling.
Yes which is why i started building a custom 20 usbc 65w max per port box and was going to swap out all barrel pluga for matching voltage usbc receiver plugs but havent finished it yet. Not sure about battery or if i was going to add one to it
Sounds interesting, do you share the project progress somewhere?
Aha! Yes.
Dunno how much juice you need, but I am installing one of these, tied into solar and a smart power switch:
https://au.ecoflow.com/products/ecoflow-river-3-max-plus-portable-power-station
Part of the reason I chose it is exactly what you are talking about. It has a direct DC output, so you can avoid the battery DC --> AC --> router power supply --> DC conversion chain. I have a bunch of DC capable gear (Raspberry Pi, router etc) and I’d rather not incur the losses in conversion.
FWIW, the car-style DC outlet supplies 12.6 V at up to 10 A, or 126 W. So it has more than enough current capacity for a 12 V 5 A router. (It also has USB power, if that’s an option for you).
You’d still need to check whether your router is happy with 12.6 V rather than exactly 12 V though. You’d also need the correct barrel size and polarity.
On the plus side, It gives you 858 Wh of storage (depending on which model you do with), a <10 ms UPS transfer time, and enough AC output to keep quite a bit of your other electronic junk alive during a blackout or brownout.
In any case, please enjoy the delicious overkill. I’ve seen the River 3 plus + extra battery on sale for as low as A$599 / 420 USD. And yes, they can be charged by normal wall socket (and also yes, the DO pass-thru as well)
https://www.ecoflow.com/au/river-3-series-portable-power-station
Since it happens to be 12 volts to your router and many UPS batteries are 12 volts… Why not just tap the two leads coming off the UPS battery and run that to the router? After you buy a replacement battery of course, they really are cheap and easy to swap.
When charging, 12V lead acid batteries have significant higher voltages (>14V), so you basically need a DC to DC converter to make sure you get a stable 12V supply. Some (typically industrial/automotive grade) systems have that built into their internal power supply and can work directly off a 12V battery, but with consumer routers I would assume that not to be the case.
Hey, I have a lot of appreciation for the infrastructure you maintain so don’t take this the wrong way: you’re very confidently overcomplicating this one all over the thread. People run nominal 12v stuff direct from battery all the time and it’s fine. It’s the norm in RVs, boats, and off-grid housing. There’s usually quite a bit of wiggle room. The router I’m using right now won’t actually cut out until ~8v and sees almost 16 during my ancient lead acid battery’s eq cycles. It’s completely fine and has been for years. Not industrial or automotive grade by any means, a low-end Netgear from the thrift store.
You also state “while there is DC power the battery in a UPS isn’t used”. Assuming you mean AC that’s still not quite correct, it’s always being charged at least a little and tapping it for DC is perfectly fine.
That’s my advice to op, and a setup I’ve run before: replace the 12v battery attached to their existing UPS and wire the router/any other 12v devices right to it. A UPS is just a nicely packaged battery charger/inverter/transfer switch. Wiring them to larger/cheaper batteries that don’t happen to fit their casings is also entirely viable, as is running either of their outputs to a load panel. Sky’s the limit :)
What router? 12v5a is 60w max, which is not an unreasonable amount of power. A 1500va UPS should power it for like two hours or more.
You could easily wire it up to something like that. Take the power cable, cut off the wall wart, connect the positive wire (usually red, could be white) to the positive terminal, the negative to the ground terminal. Cut off the head of a power lead, connect the live, neutral, and ground to their terminals on the AC side. Plug your battery in, the power lead into the wall, and you’re done. Check everything with your multimeter before actually wiring it up if you’re not sure. You do have one and know how to use it, right?
