Zigbee Switch No Neutral Issue

So I’m trying to suss out the cause of this particular behavior: when my zigbee switch is turned off it will start cycling through all the LED strip colors and the next time I try to turn on the switch with Homeassistant through the zigbee2mqtt connection it will turn off again (as in not detecting that the switch is actually turned on) and then the zigbee connection is reset and it turns on and off like you would think it’s supposed to.

This is a no neutral connection and I have found that this behavior only happens when the default light off LED behavior is 25% or less brightness. When at 30% brightness and above the switch simply turns off and behaves as you would think it should, the zigbee connection remains snappy and turns on and off as expected with the LED changing colors as assigned to defaults.

My assumption is that this is the switch momentarily fully turning off with an off command and that this is the switch resetting to default briefly as a consequence. Therefore with the 30%+ LED I would guess enough power continues through the switch to avoid this. Finally, I guess a bypass would solve this issue. But I am only guessing and trying to figure out if this is so. Or does the dimmer switch only pull enough power to keep itself on or it does not, no in between. Does the LED light change the power requirements and cause these issues or is it something else? I have no issues at all with the light bulb flickering, this is only an issue with the switch itself behaving erratically.

I think you’ve made a pretty good assessment. I also don’t think you’ll get an absolute answer on brightness percentage and draw to keep the switch powered. It’s rebooting on the lower brightness, so add a bypass and evaluate.

I got this as a response from Inovelli email, wraps things up pretty well:

Your understanding is correct. In a no-neutral installation, the switch relies on a small amount of current passing through the load to keep its electronics powered while the load is off. If that current is not stable enough, the switch can momentarily lose power and reboot.

The LED bar cycling through the colors is consistent with the switch rebooting. That would also explain why Zigbee2MQTT temporarily loses track of the switch state and then starts responding normally again once the switch finishes restarting.

The fact that this only happens when the LED bar brightness is set to 25% or lower is another good indication that the switch is right on the edge of having enough power available in this particular no-neutral setup. At 30% and above, the additional power being used by the LED bar appears to be enough to keep the switch operating normally.

A bypass may help provide a more stable path for the small amount of current the switch needs in a no-neutral installation and could resolve this behavior.