I’m building a small house on a Wisconsin farm with off-grid solar power. I’d like to have an electric heater that only runs when the house is cold and the solar battery bank is fully charged. The solar equipment is in a shed 250ft away, with clear line of sight. The charge controller can be programmed to energize a 12v, 200mA circuit at the appropriate time.
I have electrical experience and I’m fairly tech savvy, but new to the world of home automation. So I’m hoping folks here have some ideas. My first impulse was to just run direct burial Ethernet cable, and use relays to trigger a switch inside, such as on a Zooz ZEN16. It’s not a great area to bury cable, but I think this would work and cost $150 or less.
My other options..
Do it with Z-wave. I can’t find any Z-wave voltage sensors. I could probably rig a temperature sensor probe to detect 12v vs 0v. Using battery powered range extenders to relay the message seems dicey in subzero temps, but I’m open to it. But I don’t know how many I would need though. I could run wire from the shed to power a Z-wave outdoor smart plug, but it’d probably take two long sections of wire and two plugs. Or, I could use a 12v relay to energize 150ft of wire with a plug at the end. If the plug was on my mesh, it’d mean the batteries are full.
Do it with wifi. There’s no internet in the shed. I’d need some sort of extender or bridge, some Ethernet cable, and a PoE adapter. Then I still need something in the shed that will communicate the state of the batteries to Hubitat. Best I can think of is powering or not powering a wifi bulb with the 12v relay. Again, if Hubitat could communicate with it, that would indicate the batteries are full.
Do it with RF. There are remote controlled switches and relays that can operate over long distances. They have a fob with buttons to open or close the relay. If I were able to rig up a NO-C-NC relay on the charge controller so that it activated one button when energized and the other when de-energized, I could hook the RF controlled relay up to a ZEN16 in my house. I know this sounds far fetched, but these things are pretty cheap, and this is the only plan that keeps all components indoors.
Any ideas welcome, thanks!