Zigbee Problems - How to get a switch module to stay connected to network?

I’ve been having some problems with my Zigbee network. I have a switch module in my bathroom wall that is connected directly to mains power, but it keeps getting disconnected from the network. I’m constantly needing to re-pair it (by toggling one of the wall switches 10 times.)

The LQI is 39 which I believe is very low. Is there a Zigbee “bridge” or “repeater” device that I could plug in nearby to help with the coverage? I’m thinking about a “smart plug” power adapter that I could plug into the wall in the bathroom.

I’m in New Zealand, so I need an AU/NZ plug.
Found this one on AliExpress, but it’s a bit expensive.
This seems like a good option.

Any other suggestions for how to fix this and make it more reliable? (Or questions?) Thanks!

There is a in depth discussion about ZHA zigbee networks here: https://community.home-assistant.io/t/reported-lqi-values-for-zigbee-devices-with-zha-integration/232606

Theres a lot to look at when troubleshooting Zigbee.

Yes repeating devices are available. Most line powered devices like your switch are in fact repeaters.

So how many other line powered zigbee devices do you have?

How far is your switch from the coordinator? (spec says one thing, walls are real, not theoretical so youll never hit the spec distance - i always assume half and then cut it in half again to get a target distance of 8-10m between repeating devices)

What Zigbee channel are you on? What channel is your 2.4 Ghz wifi using (some channels overlap)

Is there any wifi ap within a couple meters of eithe ryour coordinator or the switch?

Are there any usb3 devices within a few meters of the coordinator or switch?

Thanks a lot for the tips! I’ll try to make some changes.

  • So how many other line powered zigbee devices do you have?

I have a total of 6 powered zigbee devices - 4 switch modules and 2 curtain motors. Lots of other battery powered motion sensors and door sensors, etc.

  • How far is your switch from the coordinator?

It’s not too far, maybe about 20 meters. But it’s inside a wall and there are a few walls in the way.

  • What Zigbee channel are you on?

I believe I’ve just been using the default channel (11.) That’s an awesome tip about changing the channel, thanks! I also found this page: Improve network range and stability → Reduce Wi-Fi interference by changing the Zigbee channel. I will try 15:

  • What channel is your 2.4 Ghz wifi using?

I’ve got two routers (shared one from ISP that downstairs tenants are using, and a personal Ubiquiti one.) They are both on Auto. I think one is using channel 6, but can’t find the other one.

  • Is there any wifi AP within a couple meters of either your coordinator or the switch?

Yes, there’s an AP right next to the coordinator, and another AP a few meters away. Good tip. I’ll move my Home Assistant Raspberry Pi and Zigbee USB stick down the hall to the bedroom closet.

  • Are there any usb3 devices within a few meters of the coordinator or switch?

Also yes, the coordinator was a few meters away from my office desk, which had thunderbolt and USB-C devices. Sounds like moving to the bedroom should help.

In conclusion, I’ll delete all the devices, set the Zigbee channel to 15, and move the Raspberry Pi + Zigbee USB stick to the bedroom. Will report back once I’ve tried it out. Thanks a lot!

Thanks again for the troubleshooting tips!

I have made a bunch of changes, and everything seems to be working well so far. My bathroom switch hasn’t disconnected yet. I’m still seeing some pretty low LQI values, but the network seems a bit more reliable and there are no severe delays.

Here’s what I changed:

  • Moved the Home Assistant Pi and Zigbee USB stick to my bedroom down the hall, very far away from the WiFi APs or USB-C devices. Connected the Pi to the network via WiFi instead of LAN. I’ve heard that this can be a bad idea, but haven’t experienced any problems so far. I have a really good router that has been very reliable (Ubiquiti Dream Machine.)
  • Changed my Zigbee channel from 11 to 15.
  • Deleted all Zigbee devices and re-paired everything - wired switch modules first, and then battery powered devices.

The zigbee2mqtt map is looking pretty good, with a few minor issues (one sensor without a link, couple sensors not connected to the nearest router, etc.):

I’ve also ordered a few Zigbee wall sockets, which I’ll just be using as additional routers to improve the network further. They should arrive in a few weeks (shipping from China to New Zealand.)

Thanks again for your help, this has been a big improvement.

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I’m glad it seems better!

Don’t get hung up on LQI if it’s working. Different Mfr’s calculate it differently so it’s only good for a relative number. If it works, just go with it.

Bad idea IF it interferes - you may have worked around that with your channel chages.

Good job - built the backbone first.

Never a bad idea…