I have an off-grid solar system. With the help of the community here, I have utilized HE to utilize extra solar energy to help with space heating needs. Here is thread where I got help to put this together - Need help creating automation for Solar project - #15 by javi
My system is as follows - when my batteries are full and there is still sunlight, my inverter will trigger a relay that outputs 120vAC. I am using the Smartest House power outage kit to sense when the inverter relay has been triggered (which "closes" the contact relay in power outage kit) and then I have a rule to trigger a Zooz Zen 25 plug in the place I want space heating. This has worked pretty well, but...
The contact sensor on the power outage kit stopped working (possibly battery failure) and the HE saw this relay as being "closed" all the time and therefore kept the Zen25 plug powered up. Luckily I was home and noticed this, but this could have been a disaster if I hadn't been home, as all my batteries would have been drained. I need to figure out a way to create a fail safe of some sort - either a rule or I need to add another device or something.
My current rules are as follows :
When the contact sensor relay is closed - turn on the zen 25 plug.
My Zen 25 plug has a one hour timer on it. I believe this is internal to the plug so that if the HE failed completely, the plug would turn off after one hour.
When the status of the Zen 25 is "changed" (when it turns off after 1 hour), HE checks the contact sensor and if it is still closed, then it turns on the Zen 25 plug again for another hour (and this repeats as long as the contact sensor remains closed).
Any ideas for a "fail safe" so that if the contact sensor on the power outage kit fails again, there would be a backup way to keep the space heater from running down my batteries. I have "hardwired" the contact relay at this point, so no more batteries, but when I hardwired the contact relay, I had to exclude and re-install the sensor to get it to work again, so I don't have 100% confidence in this contact relay. Any ideas for fail safe for my system?
Does this relay have a schematic? Maybe there are more contacts that could be connected to non- battery powered sensor. Even if not, it is possible to put something together... just takes more parts.
I have a setup that turns on and off my inverter based on battery voltage. If it is under 12.2v, it turns off, over that and it turns on. The Shelly Uni is used to monitor the battery voltage. I could have also used the Shelly Uni as the relay (I have another one that I use as a garage door opener…)
I suspect something similar could be used in this case, so that if the power of the batteries is under a certain value, it triggers the relay. There is a risk here however that it could turn it back on, as was the case with my setup, so I setup a virtual switch to detect the state, and a rule that detects if the voltage goes up or down when the relay is triggered (should go down when a load is applied / turned on; and up when it is removed / turned off).
The relay does not have a schematic and it is internal to the inverter. It probably isn't even correctly called a relay. It is an programmable 120Vac output that activates after certain conditions are met.
The battery powered sensor isn't really an issue now - I have hardwired it with an adaptor that is always plugged in. More the issue is the dependability of this sensor (?) and wanting a backup to make it fail-safe....the gist is that I never want the heater to run continuously in the event of failure from a single sensor, Hubitat failure, etc.
I no longer have battery worries as I have hardwired the contact sensor and it will be left plugged in.
I own a Shelly PM that I have goofed around with, but I don't think I can use that as I don't have WIFI at this location (at least when I am not there personally). That is one reason I was attracted to the HE since it didn't need always-on WIFI.
I need to study up on virtual switches. It seems like I need one of two solutions - (1) another sensor that I can integrate into the system as a backup to one sensor failing and/or (2) a rule that requires a regular "check in" by the HE to confirm the contact sensor is still working correctly (or that my inverter is still outputting 120V on programmable output).
I do have a used Mimolite coming from ebay - I am not very familiar with this at all, but it seemed to have possibilities when I was researching...
No, there aren't any other wires. If I was smart, there sure would be, but I wasn't thinking ahead...I think HE is neat and it has been fun to learn how to do it, but I have to say I have thought many times about running a direct line - it is about 75' run...
Thanks for the reply. Yeah, I am kicking myself for sure, since I just ran the wire last summer - I just didn't realize I would have such a surplus of energy...
I think another relay and contact switch is a good idea in the meantime. Were you thinking zigbee since I already have Z-wave devices? Would this give the best redundancy?
