I had a situation today where we must have had a powercut overnight and the smart plug powering and monitoring my refrigerator did not turn back on… So that means it has been off for a good few hours!!!
Are there any simple ways I could monitor this an create notifications? I’m thinking something like…
If power usage of the refirgerator has been less than 10w over the last hour then there must be an issue.
If I have not had an update from the smart plug in the last 10 minutes then there must also be an issue?
I have bluetooth le temperature monitors with HA alerts on my frig and freezers. While not to your target of power monitors, I have been very happy with these sensors. If nothing else, a B-plan option, as having two monitors of critical things is something to consider.
I have explored several that work. Unfortnately my favorite and the ones I am using for two plus years now are no longer made. Of the ones I tested in the fridge and freezer that I believe you can still buy:
Xiaomi LYWSD03MMC with custom firmware
Goove H5074
You can see some of my blab on BLE sensors here, sensor compares at bottom:
The Govee H5052 are the ones I am using that are out of production, what made them well suited for the cold application was that they are powered by three AAA batteries that seems to really hold up well in the cold environment. 2 plus years on a set of 3 AAA batteries.
Amazingly I have have had no issues with the BLE sensors transmitting thru the walls of the fridge or freezers, but your experience may vary. You can stuff food around the sensors too much and reduce transmission. You can monitor the rate of readings from the sensors to protect against a sensor drop off.