I love this community!! Thank you so much for your responses.
Answers to questions
I’m located in the USA
Connectivity Yes WiFi or Z-Wave.
I’m happy to flash a sonoff or and ESP if I had the time but I’m in the midst of building my home and this is the back up generator for the solar system. I’m off grid. Right now I’m looking at the simplicity of the Shelly. But it looks like it is a relay and would switch the 110v rather than trigger an Isolated dry contact. The Sonoff looks like it is also a 110v switched relay.
Level of Integration: I will be monitoring the battery bank voltage and when it gets I need to close the dry contacts and keep the contact closed until the voltage gets sufficiently high and then open the contact. I already have the Battery Management system tied into openHAB, so I have all that info already.
I have 110v power available to power the device but will not be passing 110v to the generator only shorting the line to ground.
I’d like to power the device with 110v rather than battery as this is located in a shipping container in the winter and I find the battery devices struggle in the cold and the Z-wave signals also struggle to penetrate the steel walls of the shipping container. If it is line powered the signal penetrates better and is more reliable. WiFi seems to penetrate just fine.
It looks like the Fibaro Smart implant may work but It would need an additional relay.
Thanks for all your advice!!