Power failure warning with UPS

[knuth 29]

When I am away, I would like to be warned about power failures. I intend to install a small UPS (battery backup) covering my HC2 and the router/modem, to maintain communication. The HC2 itself therefore will not sense the power failure. What do you suggest as an easy way to detect that power is out? Periodically turning on some item and checking power consumption? Testing communication with one or several units, assuming that if there are multiple failures they are caused by a power outage? Or is there a simpler way? How would you implement this in a scene? Preferably one that is triggered by the power outage itself, not by a time-based trigger.

 

 

[1152 33]

The proper UPS via a NAS or similar device/functionality could do it seperately (or if you really like via HC2). If you do not want extra computer/NAS that handles the communication with the UPS. An alternative solution would be to install a power metering z-wave device that senses the power to the ups, but itself is powered by the UPS. Then a straight forward scene triggered by the device  

[danone1973 4]

I have a very simple setup which is a relay and a Fibaro Universal Sensor.

When there is a power outage, the relay drops its contacts and the Universal Sensor is triggered. Power comes on, the relay is energised again.

[knuth 29]

@danone1973 that sounds like a good robust idea. To be sure I get it right, is this how you have wired it?

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(The 220 V AC would be without UPS supply). If this is correct, two questions:
- What type of relay do you use?

- How do you supply the 9-30 V DC to the universal sensor? A battery charger/power supply connected to the UPS 220 V circuit? A small 9V battery? Or does your UPS allow you to connect to the DC side?

 

I think I can handle the rest, i.e. to make a change in the sensor status trigger a script or an alarm ("power out", "power back on"). But I first want to get the hardware right!

Thanks!

 

 

Edited April 12, 2018 by knuth

[kunoch 27]

@knuth might be even easier if you have an older door/window sensor nearby (FGK-10x) you can use the relay contact as the binary sensor.

My APC UPS does click when the main is shut off. Maybe yours does that as well, would need some investigation on the UPS to find out what is switched internally, but should work then without any external power supply. Maybe even an adaptation to one of the status LED might do the job (CMOS relay/solid state miniature relay)

If your UPS is like the APC based on a 12V battery why not connect the universal sensor directly to the battery? I think this should not lead to excessive battery drain. Might be advisable to connect it after the UPS internal battery power off to avoid excessive battery drain if the UPS is exhausted and powers down.

If you do not want to use the UPS directly, that one (the 1000mA version) should work fine, connected to one of the 220 V outputs of the UPS:

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Just came into my mind: I have connected my NAS to a AEON wall outlet switch, but have never checked what it would report when there is no power at all. would need some testing. It is for sure some W when the power is available and UPS is charging and supplying all the connected devices. I have no clue what you see from the CHL/HC2 if the outlet has no power. I would have to test this first, but why not give it a try. Would need for sure periodic polling. If you then can make a working scene based on a no longer working device (communication error) I have no clue.

Edited April 13, 2018 by kunoch

[1152 33]

My 2p is: Stick to KISS.

1. Power play: A proper UPS com connected to NAS, monitoring remaining UPS power, reporting and controlling shutdown and tied in with HC2
2. Economy class: A z-wave power sensing/metering device monitoring the VAC-in to UPS and it self powered by UPS. (One incarnation could be like described above - but I would avoid to much tinkering with the UPS (the day you need to swap it you will thank yourself...)  

[knuth 29]

Yes, @1152, simple is good. I like your option 1, the disadvantage being the need for a NAS.  Assuming that the UPS has a serial or USB interface that allows monitoring (I have not purchased mine yet), I still wonder how you "tie this in with the HC2". The NAS software will 'know' the input voltage, but how do you pick up these values in the HC2? Maybe the simplest way in this setup is to have the NAS send the necessary messages, and not involve the HC2 at all? I am way outside my area of expertise here, so I need to understand the possibilities before making my purchases.

[danone1973 4]

On 4/13/2018 at 3:24 AM, knuth said:

@knuth

(The 220 V AC would be without UPS supply that's correct). If this is correct, two questions:
- What type of relay do you use? something like this: 

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- How do you supply the 9-30 V DC to the universal sensor? A battery charger/power supply connected to the UPS 220 V circuit? A small 9V battery? Or does your UPS allow you to connect to the DC side? You can use any of this I guess. However, in my case I have a small 12VDC powerpack plugged into the UPS. The UPS lives in my networking cabinet and I use the same Universal Sensor to also get the temperature inside the cabinet and alarm in case of high temperature.

Hope this helps!

 

I think I can handle the rest, i.e. to make a change in the sensor status trigger a script or an alarm ("power out", "power back on"). But I first want to get the hardware right!

Thanks!

 

 

 

[knuth 29]

Thanks, @danone1973, that defines one workable solution. I will study the spec for my UPS (to be suggested by my electrician) and then make up my mind on what set-up I will use. Both you and @1152 have suggested interesting solutions. 

[knuth 29]

Still in the planning stages, this is what I am now considering as the most likely choice: 

A Raspberry Pie microcomputer plugged into the USB port of the UPS (for both power and communication). The Raspberry runs a small program checking the AC power status, and reports to the Fibaro system (LAN or WiFi). I need to define the Raspberry as a virtual device, and use this as a trigger for the power failure alarm. Any comments or further suggestions? 

[AutoFrank 372]

A pi running NUT (

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 ) connected to most UPS via USB cable  will yield a lot of data (load, runtime, status, etc) 

there are a couple of VD's already published that can work with NUT in providing a solution

[knuth 29]

Thanks, @AutoFrank , that looks like a setup I can use. I checked my UPS (a BlueWalker PowerWalker UPS VI 600 SC) against your documentation link, and it is supported. I will decide later whether to use the input voltage or some other parameter as my trigger.

We have plans to install a Raspberry pi anyway, so extending its use to monitor power failure seems to be a robust solution.