Power Off TrueNAS when power goes out with Athom smart plug for sensing with HA

[cosmic elbow]

So I am using home assistant just as a means to an end (for now). I have 2 esphome athom smart plugs. My UPS is dumb so I was thinking that I plug the UPS into the wall through the smart plug and when it goes offline due to a power outage, home assistant will send a shutdown to the trueNAS server via its REST API.
https://www.athom.tech/blank-1/uk-v2-plug-for-esphome

I am a complete noob when it comes to smart home stuff so if something here sounds stupid then is probably so I am all ears for alternatives. I have manually HA installed on the TN server in an ubuntu server VM that has pihole, unbound and tailscale.
Now some quirks. It seems when the smartplug loses power, home assistant doesn't show it as unavailable. It reports the last received value until it comes back online and then goes unavailable for a second.
The power sensor reports every 5 seconds so I was thinking if the sensor data is stale for more than 30 seconds it will send the shutdown then unless you guys know how to to fix the thing not reporting as unavailable.

The solution needs to be pretty immediate. I might get a Pi in the future that will always stay online and work as a kvm. Thanks for reading.

[zealous ore]

I don't know how good the athom sensors are, but a more effective method might be to have one plugged in to something that always consumes some power and assume a power cut if that goes to 0 for a few seconds
That said, isn't the point of the UPS to keep your server running when there's a power cut? it seems counterintuitive to turn it off when there is one

[cosmic elbow]

Then the USP will run out and it'll be less than graceful. Also if the thing is going to zero the smart plug is losing power. If have to manually turn a thing off to lower power through the sensor then I might as well hit the button. This is so that I don't have to rush to it to turn it off before the ups give out and so that I can use the server unattended.

I guess if the smart plugs are bad I could also do it by pinging the second wireless AP in my house and send a shutdown from HA if it doesn't respond for more than 30 seconds.

[zealous ore]

Those plugs also seem to just be running esphome so you could probably change their behaviour on losing power, but not sure how to do that

[jagged forum]

Why not just use the UPS service in TrueNAS itself? This is already baked-in functionality. Not sure why you would need a smart plug.

[cosmic elbow]

I am not sure how the UPS service in truenas is going to know it is now on battery and not on wall power

My UPS doesn't have any management features.

[jagged forum]

It doesn't need any management features. Basically, the upsd service can detect when power is coming from battery or mains.

[cosmic elbow]

The ups doesn't have any way to talk to the server

It can tell if it's on battery?

[jagged forum]

Does the UPS have a USB port on it? If so, then you can connect it to TrueNAS and use the upsd service to monitor it.

[cosmic elbow]

No it doesn't. This is why I'm doing the jank.

[cosmic elbow]

It is difficult to find a proper online or line interactive UPS with shutdown features here

[jagged forum]

Ah gotcha. Sorry about that. Even the cheap ones here have a mgmt interface. 😔

[cosmic elbow]

Sod it I'll get new one. I've found a used APC smart ups 750 for round what would be about 50 bucks. I think the model is about 15 years old. If the batteries are shot can replace them. Are there other parts in it that might have degraded?

[jagged forum]

Not that I know of. The batteries are generally the part that goes south. The rest of it is pretty age-proof.

[cosmic elbow]

Can I throw in just about any SLA battery or are they picky about it?

[jagged forum]

A friend of mine recommended mightymax batteries as replacements.

[cosmic elbow]

I'll look for them locally. What should I search for ups batteries? Do they all use the same form factor?

[jagged forum]

No. If you know the brand and model, you can just google replacement batteries for it.

[cosmic elbow]

All the 12V 7Ah SLA look the same that's why I'm a bit confused

[cosmic elbow]

How do I make sure the battery I order actually fits the thing? The model I am looking at is a sua750i and it takes either a rbc6 or 7 and I see people also putting in 2 12V 7/9Ah SLA battery if they have the harness. This is pretty confusing as the batteries them selves don't have a name for their format.