Thank you. Yes that definitely seems to simplify things.
I use a time delay relay connected to a iris switch. The time delay forces it to stay off for about 1 min to get a good reading.
I haven't had a bogus mains disconnected reading since the date of this post, 4/5.
Knock on wood. 
I'd like the Chime Siren anyway:
"The Gate Has Been Open For A Long Time", lol.
That reminds me though, I should test the smoke/co detectors.
My device reported Main/Battery many times per day.
It mut be defective. Otherwise yes, very nice toy.
For the Power Monitoring I have two Ring V2 repeaters. One is on the solid circuit but second one is on the GFIC Laundry Circuit. This laundry GFIC gets tripped few times per year but thanks to the two Ring repeaters I immediately know when this happens.
Is it possible to monitor a device that has a voltage attribute. Reason I ask is I have a hot water heater smart switch, which shows the state of the switch, the power in watts, the voltage in v and the current in amps.
I want to monitor the voltage so that if it drops below 180v for 60 seconds then I can assume we have lost grid. Currently I am unable to see this as an option to select to monitor only the actual switch itself.
I just did it with a ZEN04 switch.
Custom attribute in the driver includes voltage.
"Custom Attribute" is what you want.
Doesn't look like that's an option in the current version of that app - you could post a feature request in that app's main thread to see if such a thing may be possible.
Velvetfoot's advice above would apply if you were to create your own rule in Rule Machine.
I have setup a rule machine for now and posted in the correct thread. Thanks lets see what happens.
Yes, but only if device is still functional. This may not be a case if device does not have a battery backup.
Okay, this will not have a battery so it might not work??
This is an excellent point that I completely forgot about... I'm not at home to verify, but I think the only devices you can use with the Pwr Outage Monitor app are ones with a fail-safe battery backup -- e.g. ZAC38, Ring Extender v2, or a Titan with the optional battery pack.
... plus Ecolink Chime Siren. And of course, hub itself on UPS.
All you need is a cheap relay that is no or nc with power (like a 5v relay) power it off usb, then from the relay solder to a door/windows magnetic contacts one on each side. (Add the contact to habitat).
Then when the Relay is powered (NO contacts) so now closed it will show the contact as closed, when power is lost then the relay contact will go to open and the door contact will show open, hence knowing the power was lost.
Or if Relay is powered (NC contacts) so now open it will show the contact as open, when power is lost then the relay contact will go to closed and the door contact will show closed, hence knowing the power was lost.
Cost $15 (each if you do 4)
Cheap Door Contact $11 - Amazon.com
Cheap 5v Relay $7 (4 pack) - https://www.amazon.com/AEDIKO-Channel-Optocoupler-Isolation-Support/dp/B095YD3732
Cheap Project box (4 pack) (Optional but recommended) $9- Amazon.com
They also make 12v relays you can use. I used 5v because I had so many laying around the house from shucked hard drives.
This has worked without issue for years now.
I also used a Fibaro Implant for the relay and added 3 temp sensors for my deep freezers
Update: I am in the process of trying to order parts to make a handful of these to sell since it seems nobody has anything. Also created a custom driver that will have a powerStatus of on or off to show if there is power loss
The key item here, if I'm not mistaken, is that the contacts of the mains powered relay are connected to a battery powered contact sensor. As long as the hub still has power (and any necessary zigbee/zwave repeaters) the state of the relay should be communicated to the hub.
The contact sensor is what communicats with the hub and is battery powered. The relay is connect to mains power and when powered it make the contact show open, if power is removed from relay/mains loose power the contact changes to closed.
Along this same line of thinking ...these current sensors can be connected to your favorite Zigbee or ZWave contact switch with some simple soldering (or find a Zigbee/Zwave device with wire-able contacts).
Been using one for a number of years now in a pretty harsh environment to sense a pump going on/off. (I worry more about the Zigbee contact switch than I do this current sensor.)
But the more you guys are talking about power outage sensing the more I think I might pull my spare out and use it to sense Mains power.
There is no power input to these, battery or otherwise, as the current it picks up from the single wire that you place through the coil runs the LED and onboard switch.
Series CCS Current Switch | Dwyer Instruments (dwyer-inst.com)
But the price. I would just as well use the relay for the price.
I haven't fooled around with a CT relay yet. It seems like experimenting shouldn't be too costly. Maybe you could wrap one around a dryer conductor in the panel and have a contact sensor outside.
Not to derail the thread or anything
Yeah, it's a bit more...but these are used in Industrial Automation & Process Control and are extremely reliable with long MTBF whereas the relays we typically buy are all over the map on longevity and reliability.