Hubitat has control of my 13kw Generac

Hubitat has control of my Generac Generator. I see posts about monitoring Generac generators but not much on controlling them, so I thought I’d share. My dashboard allows me to shut down and start the generator, and my automation in away mode runs a rest/run cycle to cut down on propane use. I had to build a small control panel to get the control, but I did not have to hack into the generator controls (much), and transfers, gen starts, and stops function as per OEM design. The shortlist of what I did was have a z-wave switch control a relay that feeds an alternate 220vac signal to the sense wires of the transfer switch logic board. The transfer thinks the power came back on, does a transfer to utility power, and shuts down the generator. The alternate 220VAC signal comes from a small 120VAC UPS that passes through a step-up autotransformer. Hub and internet are kept online via a large separate UPS during no power periods. The system is installed at my Canadian cottage that cannot get propane delivered in the winter, so I only want the generator running when required to protect plumbing or keep food cold. Does anyone else have control of their generators?


Very creative.

And just more evidence that many implementations of HE are indeed "more than just turning on the lights" and therefore warrant all the resilience that can be afforded in it.


My away mode rule was a bit of a challenge (for me) due to the error processing element. Unlike a light bulb, having an unattended generator flash on and off would be a bit more problematic. :blush:

Posting the control drawing, and some pics of my control in case someone in the future is out looking for ideas.

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Hi. I saw your recent thread on gentek.

I guess I don't understand a key point.

I can see spoofing the generator controller by supplying 240v to N1 and N2 going to the controller, but since the transfer switch flips over to a dead utility line, your battery powered 240v must also supply 240 to the utility side coil of the transfer switch. If it does that, can't it also get past the transfer switch and out to the utility feeder?


The spoof voltage is applied to the transfer switcher controller, not to the utility lines of the transfer switch.

I added a 4PDT relay in front of the transfer switch controller. With this relay off, the utility power (L1, L2, and N on NC contacts) is connected to the transfer switch controller, and the transfer switch works as designed. When the relay is energized, the utility power sensing wires are removed from the transfer controller and replaced with the 'spoofing' voltage. The transfer controller sees the 240V signal, does a transfer to the dead utility side, cools the gen down, and shuts it off.

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Thanks. I'll have to study the manual more.

Here is the schematic of my gen control circuit.

Thanks. I think I'm understanding more now. The 240v ('utility') feed into the transfer switch controller (SACM?) can either be from utility or battery. That's where the source to power the transfer switch's utility coil comes from.

Based on an old post on one of the generator forums, I thought about changing the wiring in the transfer switch so that the generator would power both coils. So, you could switch it back and forth as long as the generator was running. Then, you have to find a way to turn the generator on and off. Your method keeps the Generac's controls intact. I like it, but likely too complicated for me to implement.

Then, of course, there's the 'warranty', lol. Reminds me of when I was "hot rodding" my VW TDI.

I tried to get a gen setup with two wire on/off, but that did not happen as the timing was in the middle of all the Covid delays. I did not want to mess with the controller and its generator control functions so I decided to try to trick it. It works well, but it's certainly NOT plug-and-play.

Track days with a full warranty. Never been there....maybe just as well.

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