FAQ: 32 Zigbee direct connection device limit?

V3 hub does. Just paired a new water sensor by QR scan last week.

1 Like

Yeah, I did the same with 20+ sensors. Some multiple times with the whole hub upgrade debacle. Didn’t even put the QR code discovery + ZigBee 3.0 together in my head until you said that and I double checked my hub info.

But the rest of the question remains about the limits and v2 upgrades.

v3 supports 64 child devices.

Endpoints are kind of like ports in TCP/IP communication - basically different applications on a device. Most devices have 1 or maybe 2 endpoints. The child device limit is the number of end devices that can connect directly to a node on the network like the hub and it isn’t related to endpoints.

Yes, we do plan to update v2 to Zigbee 3 in the future and the limit will be increased at that time.


It would be helpful (and honest) to existing/prospective SmartThings customers to mention this limit (as well as 32 end-device limit in V2) in the SmartThings FAQ. The FAQ currently implies that SmartThings supports unlimited number of Zigbee devices.


I am using the Xiaomi power outlet and is sold on aliexpress for about €20 for a euro version. Works well as a repeater for zigbee

Bro @MagnusBergs
Did you mean like this Xiaomi zigbee plug you are using as zigbee repeater??

When I power off a Tradfri bulb in the loft, the Aqara window sensor drops off within the hour.

1 Like

Do you have an ETA for that release? I’m currently stuck with half a house of non working bulbs and contact sensors. It took a lot of hair pulling to come across this post as the 32 device limit is not called out in the SmartThings documentation. If it’s going to be a long time before a real fix will be released I will use the repeater work-around. I understand this defect probably doesn’t impact a lot of your users and may be a lower priority but it does impact your power users.

1 Like

That’s a 32 device direct connection limit, not a 32 device limit. There are plenty of Zigbee bulbs that are known to be poor Zigbee repeaters that could be the source of your problem. Real power users have repeaters in every room to ensure a properly functioning mesh. This is not a smartthings issue per say… but more Zigbee by design.


1 Like

To clarify this point, every Zigbee radio stack has a limit of how many devices can connect directly to it. 32 is a fairly standard number, Lowe’s Iris, SmartThings, and Hubitat all have the same limit. You can easily extend the number of devices you can connect by adding routing devices like SmartPlugs which can each directly connect to 6-8 devices, or more.

You can see how you can easily expand your mesh capacity and physical coverage with just a handful of routing devices.


FWIW - I guess I’m a “power user” because my home currently hosts 307 devices, 109 of which are Zigbee devices. All connected to a ST V2 hub and all working just fine, thank you. And most of those Zigbee devices are battery powered end nodes, to boot!

As previously noted, the trick is to distribute enough A/C powered Zigbee devices that will act as repeaters throughout your property. For me, that means at least 1 Zigbee wall switch in every room, plus a few SmartThings SmartPlugs around the exterior perimeter of my house (to pick up the 26 Zigbee Spruce lawn moisture sensors scattered across my 2+ acre lot).

One other important consideration: you want to make sure that the Zigbee channel your Hub is using isn’t overlapped with another Zigee device (e.g. Hue) and/or your WiFi channels. Such overloaps could limit the number of devices you can (reliably) connect.

Since the Zigbee channel gets auto-selected by the hub at initial install, and cannot be changed later, you might have to install/remove your hub a couple of times until it selects an out-of-the-way Zigbee channel. My ST hub uses Zigbee Channel 24, my Hues use Zigbee 25, and my WiFi uses channels 3 and 8 (I have neighbors on 1/6/11). More info on Zigbee/Wifi overlaps is here:


Sorry for the necro here…

“In theory” the Hue bridge has a 50 bulb limit. In my experience, anything over 30 devices (sensors, dimmers, and taps) causes huge delays in the hub processing.

Maybe it is just my hub, but I have a few friends and they all have the same issues. I personally recommend the Ikea Tradfri bulbs connected directly to SmartThings, without the custom Tradfri DTH (just connect them as regular ZigBee light link devices). They have the benefit of acting as repeaters, and are the cheapest bulbs you can get if you have an Ikea nearby.


This is really helpful, thank you,

I am a UK user and wondered if you knew if any reliable power plugs that I could add to my network to improve connections?

Also - (forgive my lack of knowledge) - will doubt this allow me to add more than the 32 Zigbee (xiaomi in my case) ?


1 Like

Most any Zigbee device that is mains-powered will act as repeaters for other Zigbee devices.

It may take a day or two, but eventually (up to 32 of) the powered devices will wind up direct-connected to your SmartThings hub, and the non-powered will reconnect to one of those repeaters. This will allow you to support an “unlimited” number of Zigbee devices (as I said, I use over 100 currently).

So to be clear: the 32 Zigbee device limit for your SmartThings hub ONLY APPLIES to the number of devices that connect directly to your hub. Each of those devices can in turn support some number of additional “dependents” (typically 8-64 each, depending on the device).


Thanks, maybe you can help on this i posted in the forum the other day too.

I have Smartthings Hub v1, and have 30 odd Xiaomi devices added to this setup using the a4refillpad DTH - they all work great. I am now trying to add two additional Aqara Motion Sensors to the setup but i cannot for the life of me get them connected. I have followed all the helps topics, hold for 3 seconds, wait press again - replaced batteries, but still nothing showing up in CatchAll.

Would you know how i could troubleshoot this?

I am not sure the aqara devices work with the V1 hub. But that’s getting pretty far off topic for this thread, which is an FAQ on the number of supported child devices, so why don’t you take Xioami/Aqara questions to the following thread and someone there should be able to help you:

With regard to zigbee repeaters that work well with smartthings, including with Xioami sensors, The best right now are probably the IKEA Tradfri plug-in pocket sockets. These are very inexpensive, £9.97 in the UK, and are available in many different countries with the appropriate socket type. It’s just a basic on/off device with one socket, but works well and, as I mentioned, is a good repeater. The Tradfri Smart bulbs also work well. (The handheld buttons and remotes, though, only have a partial integration so most people skip those.) The product description may say they need their gateway, but you can use the smartthings hub instead.

Don’t know how many children they can support, my guess would be three, but it might be five or so. :sunglasses:


Thanks JDRoberts.

I have 3 connected and working well for over a year so i know that they do work, just the two i have at the moment won’t connect at all. I’ll try your suggested link post.

IKEA - yep will go and get one of them and test it out.

Thanks for the quick response!


@tpmanley here we are two years in the future. Was a later hub firmware able to bump the end device limit on the V2 hub? :slight_smile:


Pretty frustrating not to have ability to see the status of these enhancements. Just old threads with old attempts and zero communication about it after the initial teaser. Whatever happened to assigning folks like us to problems/enhancements so that we can be notified when you actually fix something — and even test for ST when they think it’s ready. Makes me want to try Hubitat since it hasn’t yet been swallowed up by a huge conglomerate and they may listen more.

Honestly, I wouldn’t count on this happening any time soon (and probably never for v2), but regardless, some limit along these lines is inherent for every Zigbee coordinator (hub) and router (repeater). Hubitat, for example, also has a 32-end-device limit (it’s also great if you like local processing— I do :slight_smile: ). The v3 ST hub has a 64-device limit, as mentioned above. In either case, this is far less than the maximum theoretical number of Zigbee nodes (tens of thousands?).

The solution for more devices in either case is to add repeaters to your network—the limit isn’t on total Zigbee devices but just “end devices.” Repeaters also have their own limits, usually far less, but each adds at least a few more (I have an ST 2018 outlet that maps with 6 devices repeating through it now, and I’ve seen Xbees with a lot more). Repeaters are good idea to have for range regardless (even if you’re within theoretical Zigbee specs, you never know without RF goggles what is actually an obstacle for your hub or device).

1 Like