Any UPS / battery backup solutions supported by Home Assistant?

I’m in the market for an UPS solution that will bear roughly 300-400 watts (my low-power server rack) for over an hour.

Traditional UPSes seem to be absurdly expensive for anything above 10 minute runtimes. To add insult to injury, most UPSes would require serial or USB cabling to integrate into HA (all tricky, given how the machines are put together, and especially tricky if I wanted to add a second battery backup in a different room where there’s only Ethernet); those battery backups supporting SNMP often cost hundreds of dollars more with no additional capacity. That is without taking into account their often-garbage battery technology and durability (most are still using lead acid!).

I have looked into the Ecoflow Delta Max and Delta 2, and they are certainly up to the task. I really like the Ecoflow products, and I think (based on YT videos of tests) their River 2 can tide my server rack over easy (30 ms switch time, good enough for standard PC power supplies). To get to multi-hour run times, I was looking into their Delta series (which kick in 30 seconds after an outage).

Sadly the Delta Max is out of my budget (roughly $1000) an the Delta 2 has an OK price, but it not supported by the GitHub - vwt12eh8/hassio-ecoflow: EcoFlow Portable Power Station Integration for Home Assistant integration. Cloud integrations are out of the question simply because a power outage almost certainly means I cannot monitor my UPS using Home Assistant — and, of course, why do I need to give Ecoflow my power data to begin with?

So, what solutions are there available for those of us who want to power a moderate load uninterruptibly, within a (fairly generous but not datacenter) budget, and integrate with Home Assistant? Anything like Ecoflow that integrates with Home Assistant (and hopefully is cheaper / can get me more runtime for the same money) would be absolutely wonderful to hear about.

Thank you very much in advance for your ideas.

400W is not low-power… that is a lot of juice needed to keep up for more than 10 minutes and is not going to be cheap regardless which path you choose.

My rack with 4RU server, Unifi 24-port POE switch powering 10 x cameras/3 x APs/2 x downstream switches, Unifi NVR, Unifi router, fibre bridge and backup 4G modem consumes 210-250W (more at night when camera IR is active).

I use an Eaton 2RU 1750 UPS with an additional 2RU battery pack which gives me close to 2hrs down to 30% battery. The UPS by itself gives about 35 minutes to 30%. It is USB connected to the server, and I use NUT running on the server to control shutdown, but I do use the NUT integration on HA (which runs as a KVM virtual machine on the server) to integrate the UPS state into my home automation.

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Thank you. I doubt I will be able to make NUT work given that it’s going to be hard to both cable an USB wire from where the UPS will be.

Even if I did that, when the HA VM boots up, it will assign random /dev/ttyUSB? device names to any USB serial adapters connected to the machine, meaning that NUT will sometimes try to open the ZigBee device as an UPS, and HA ZigBee will sometimes try to open the UPS HID device.

How much money did you pay for your UPS + extra batteries setup? You have an Eaton 1750VA which has juice only for 30 minutes on 250 watts. For the cost of the UPS alone you could have purchased a comparable Ecoflow battery and you would have had 10X more juice. I can’t imagine how much more expensive the Eaton setup would be with an additional 2RU battery, but I would love to know.

I have a APC ES700 which should be able to backup my server rack for around 45-50mins. The UPS was fairly cheap and the batteries just need changing every 5 years.


The serial cable is connected to a Synology NAS via a 4-port USB extender, I run HA in Virtual Machine Manager and have never had any issues with the USB device changing after a reboot.

Maybe there’s a way you could extend the serial connection for your setup.

Sadly that is not how Qubes OS works. USB attachments are attached in random order and therefore enumerated in random order. (Perhaps one way I could get around this is by attaching the USB peripheral to a separate VM just for NUT, and network from HA to NUT… but that still leaves the matter of the USB cable itself).

What sort of wattage is your setup normally consuming? I am skeptical that a 700VA UPS can power a 200 watt load for 40 minutes. The graph here clearly tells me that you must be running a load of 70 watts or less, which isn’t even a single PC with two rotational hard disks:

You should be able to specify the device by serial id instead.

My Eaton 3S 700 died this week so I’m looking for a new UPS too.

Had not considered the Ecoflow until now. The mini might do the job for me (160W day / 180W night loads).

Yeah, even the tiny Ecoflows are beasts compared to UPSes, and they have one that switches in under 30ms (I saw a YT video tested with a PC and a simulated outage — worked fine). And the price… much better bang for your buck.

You should be able to specify the device by serial id instead.

This would, sadly, probably not solve the conflict of ZHA wanting to use the wrong serial device. I want to be certain that I’m not going to have this problem every time I restart the HA server VM, before I plonk $1000 in a fat battery.

I have multiple USB comms devices passed-through to my HA VM with no issues at all, I’ve never had an issue with USB devices getting confused on passthrough, and never a USB device passed through that was not supposed to be. A VM OS that cannot handle USB passthrough would be a hard no for me.

My setup is a single self-contained and secure comms/IT rack - locked, power-independent and power protected for 2 to 3 hours. That’s the way I needed it. Yes it was expensive (base UPS about AU$900 + extra battery) but justified for my use case. I don’t want separate Ecoflow-type power backup.

It wouldn’t, and he didn’t say it would. The 700VA UPS he uses is at 16% load, indicating he’s pulling about 100W of power, so not far off equivalent time to my 220W on the 1750VA Eaton.

Thanks. Yep, I’m going to need a bigger battery :smiley:

Using serial id is exactly how this issue is resolved, search the forum.

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My server draws < 100W. It’s an AMD Ryzen 7, 64GB RAM, 8 x SSDs, 1 8TB HDD, 6 fans, with some reasonable care taken in BIOS to make it power-smart. EDIT - and it runs 5 x VMs 24x7 - mail, web, DNS, HA, & whatever else I throw at it :smiley:

Oh. The Ecoflow is not suitable as a UPS. The switching time is too long (30ms).

I’m not sure how long it would last in reality but I have survived a power cut of over 20 minutes no problem. Also the UPS is monitored via the Synology so that it shuts down gracefully when the low battery threshold is reached.

The rack is powering a 4-bay Synology NAS, 24-port switch, Router, and an AP. The UPS is rated 700 VA and it reports a load of 16% which I suppose indicates 112VA.

The APC website actually has a runtime calculator although that needs the power in Watts which I don’t have (guess at some stage I need to stick a clamp meter on it to find out).

Update … I iteratively changed the power in Watts until the capacity hit 16%, this occurred at 66W and gives a runtime of 49 minutes which ties-up. I do however accept that these figures may not indicate real-life usage.


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I saw a video with a PC surviving the transition fine. Perhaps this is not good enough for server grade machines, but it seems fine for PC style power supplies.

If the Ecoflow River 2 won’t work, a small UPS for 5 minutes in front of the large Ecoflow should do it.

That said, I am looking for devices similar to the Ecoflow but with actual integrations with Home Assistant.

They don’t recommend it:

Yep, it’s true, but it does work for most desktop computers as they have enough capacitance in their supplies.

Technically you’re supposed to get a line-interactive or fully online UPS for those devices. Guess what, almost nobody that doesn’t run a datacenter does that, because the cost can be that much more than just the entry-level switching UPS which also wouldn’t work with a 2U server.

I thought I would like to complete the circle by noting that I bought an EATON 1500 VA UPS and, after a “quick” deploy of NUT, I am supervising its state in Home Assistant, and automating power shedding (turn off non-critical servers 30 seconds after going on battery, an turning off all other machines when power reaches critical levels).

My biggest surprise was to learn that I only really get 10 minutes backup with all monitors on, whereas powering all monitors off, or getting them into power save mode takes that up to 20 minutes… and powering off the nonessential servers gets me to 45. Whoa.

Does HA support UPSs with a USB HID protocol?
I got it running on a thin client with the generic 86-64 HA build. Together with my router they consume about 37W. Looking to keep them both running for several hours but it is not obvious how long they will last when sellers only give VA or W!
I want to be able to shut HA down gracefully when the capacity left drops to say 20% and then come back on when power is restored. But if the power comes back on after HA shuts down, but before the UPS gets to 0%, then HA (or rather the BIOS) won’t know it’s safe to reboot! How can I get round that?
I also want to be able to run an automation on reboot triggered by knowledge of a power outage. How can I do that?
Several questions there…

What model UPS?

I’m just browsing them on Amazon. Haven’t come across any that mention NUT, but several mention USB HID. This is just one of them - Eaton 3S 700B UPS.Don’t want to spend more than £100 (UK).