Zigbee Repeaters and Max devices

For those who are looking for quick answer please scroll down 1/2 way through my post.

So I started automating my home when I was in a condo and started with the ZWAVE in wall switch/dimmers from AEOTEC. I purchased the smart things hub and it was great for my use.

When I moved into a bigger single family home I wanted to automate all the lights (at least on the main floor).
The problem I was running into was with 3 way switches. I purchased GE switch thinking I might be able to wire it but couldn’t (not really good with electrical wiring).

So I started looking at alternatives, Philips hue was one but it was too expensive at the time and I had about 60 + bulbs I wanted to replace hue had a limit of 50(mostly BR 30’s and A19’s). After seeing the limitation I started looking at the bulbs that would work natively with Smart things (as from my understanding at that time ST has hight limit of number of bulbs/ devices it can support). This is when I came across Sengled Brand of bulbs that works directly with ST hub, So when a good deal at Home depot presented itself I bought over 70 bulbs to replace every single one on the main floor. This was back in June/July.

I paired about 30 to 40 devices including 1 Smart things outlet and rest Sengled LED bulbs. After adding about 38 to 39 Sengled bulbs I could not add any new bulbs. I tried multiple things to fix the issue, I contacted Sengled support (which was useless to be honest), restarted hub, moved locations but nothing helped. Eventually I gave up and blamed the bulbs thinking there’s an issue with them. Since HD has a generous return policy I thought I’ll return these , This was back in july. Then I got busy with work and setting up the house, completely forgot about the bulbs until black friday.

I saw a deal on Amazon for the Sengled bulbs pack of 8 and bought them thinking I need more bulbs anyway and thought will exchange the ones I already had or claim warranty. I also purchased some ST multi purpose sensors. I first tried to add the ST Multi purpose sensor, even that wasn’t being recognized by the hub, after checking online reviews thought these are just PITA to sync, lets try the bulbs now. Now when I started to install the bulbs from the new pack the hub would still not recognize any new bulb. This is when my suspicion grew.
Even though It was right there in front of my eyes the whole time, I did not see that the issue could be with the Hub. I just blamed it on a bad batch of bulbs even though it was highly unlikely.
I then started researching my specific issue with Sengled LED bulbs, could not find any information.
Then I just decided to reset my hub to factory default removing all the devices I had already paired.
Once Reset the first device I paired was the ST multi-purpose sensor, I had a very clear outcome of this try in my mind. I knew it will be a pain to pair it but to my surprise the hub recognized it immediately on first try.
I was really excite and started pairing bulbs that were already paired previously thinking the issue is resolved.
Now when I again reached about 32 total zigbee devices my hub stopped recognizing some of the bulbs that were previously working.

I immediately called ST customer support, after talking to the rep on the phone and some trouble shooting he realized my hub wasn’t searching for any zigbee devices when trying to add new zigbee bulbs.
He dug in a little more and told me that Smart things has a hard limit of 32 devices for these kind of bulbs (Bulbs that are End devices / don’t act as a repeater).

He asked me to add the ST outlet and as soon as I added it i could add few more bulbs.
So now I had option of either returning the bulbs back to home depot (later found out my return window had expired 2 weeks ago) or add some repeaters/routers.

I posted my experience on this forum and @tpmanley confirmed this limit. Below is his reply to my original post.

Also @JDRoberts recommended that I try CREE connected LED as that works as a repeater/router or try some zigbee plugged in devices like outlets. He also recommended that I try to figure out how many devices each kind of repeater/router supports as the Sengled bulbs are growing in popularity.

I found some good deals on ST outlet so bought a few, bought 1 Lowes Iris outlet. Both of these works as zigbee repeaters/routers. Lowes outlet I believe works as a Zwave repeater also but you have to add it a little differently(I didn’t).

Anyway now getting to the point of the post (LOL, I know long Post. Sorry). I did some testing yesterday to find out how many devices a repeater/router can support and below are my findings.

**I tested with 32 total Zigbee End devices already connected directly to my ST hub(30 non repeating Sengled LED smart bulbs, 1 ST Motions sensor battery powered, 1 ST multi purpose sensor).
**I tried to add the same bulbs every time.
**Whenever I hit the max end device limit with repeater/router I unpaired 1 bulb and tried to add another bulb again to make sure it is recognizing the last end device and I have actually hit the limit.

I will provide 2 numbers below for each product I tested
1> Max zigbee end devices on ST
2> Number of devices the repeater can add.

The reason for me providing max zigbee end devices is because one of the repeater is counted towards the 32 Zigbee devices ST hub limit. Which means that if you have 32 zigbee end devices already connected to the hub you will not be able to add this repeater to ST hub without removing another paired zigbee end device.

Cree Connected LED
- Max zigbee end devices on ST - 35 devices (this number includes CREE led bulb)
- # of devices repeater can add - 3

(31 Zigbee End Devices on ST Hub, added–> 1 Cree Connected LED for total 32 then was able to add–> 3 Sengled bulbs)

After adding Cree bulb to ST hub as 32nd device, it let me add 3 more Sengled bulbs.

*Note - This is the repeater I was talking about above. It needs to be within the 32 end devices limit of ST hub as it is counted towards the limit( or if you use another repeater like ST outlet it needs to be within the Max supported end devices limit combine of ST hub and Outlet) CREE connected led bulb will only pair with the hub when its within the Max Zigbee end device limit.

SmatThings Smart Outlet (F-OUT-US-2)
- Max zigbee end devices on ST - 39 end devices (this number does not include ST outlet as its not
counted towards the limit)
- # of devices repeater can add - 7

(32 Zigbee End Devices on ST Hub, added–> 1 ST Outlet for total 33 devices then was able to add–> 7 Sengled bulbs)

ST outlet does not count towards the 32 end device limit. I added it on top of the 32 end devices already paired with ST hub and it paired without any issues.

After adding this outlet I was able to add 7 more Sengled Led bulb.

Lowes Iris Smart Outlet(3210-L)
- Max zigbee end devices on ST - 45 (this number does not include ST outlet as its not counted towards the limit)
- # of devices repeater can add - 13

(32 Zigbee End Devices on ST Hub, added–> 1 Lowes Iris Smart outlet for total 33 devices then was able to add–> 13 Sengled bulbs)

Not sure what factors affect the total number of end devices a repeater / router can repeat.(Maybe someone with info will chime in here).

I will be ordering a Centralite Smart outlet as I have read that Lowes Iris outlet is just re branded and repackaged Centralite outlet.
Hopefully Centralite will be able to add 13 more devices like the Lowes one.

For $ to Devices repeated, even with the Lowes Iris outlets current price of $38 it provides a better value compared to ST outlet.
Now if Centralite smart outlet is able to support 13 devices it would be a great value at its current price of $30(it has gone for $20 few weeks back).

Let me know if you would like me to test any other scenario or if you have any questions.


Nice work! Thanks for sharing this information. :sunglasses:

It’s totally up to each manufacturer what the maximum number of children is for a repeater device. It requires additional memory to handle each one, so there is additional cost when there are more. It often just depends on the overall specs for the device and what they have room to support without adding additional cost.

This also means that the number may change after a firmware update, so that’s just something to be aware of.

They are not identical devices at all – – the Centralite smart outlet does not have a Z wave repeater in it, for example.

Rather, Centralite is a company that sells devices to many different other companies that then sell those under their own brand. So centralite is the original manufacturer of many models for many different brands (including the first two SmartThings – branded zigbee pocket sockets, although I don’t believe they manufacture the current generation). As with two gig, there may even be two models that use the identical case, but have very different firmware or even different components inside.

Centralite does manufacture the iris smart plug, but that’s a different model than their other devices. So there’s no telling how many zigbee children A different centralite model will accept.

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This is definitely good to know. I read it on Smartthings community, guess should have read some replies as well.
I think I’ll still give it a shot given its price but honestly Lowes iris outlet is the way to go even at current price, would be even better if we pick it up discounted.

I got the ST outlet for $24.18 each incl tax it is still $0.50 more expensive per device to repeat than Iris outlet.

Thanks this is really good information. Do you know of a way to tell if/when a new firmware for these outlets is pushed (like notifications in ST app) Or is there a way to stop these devices from auto updating firmware ? I just want to see if I could keep a track of the changes in child devices supported with firmware updates.I’ll try to search this info as well.


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In need of a repeater, in a location that does not have a power outlet, but does have a light socket, I tried both the Cree Connected LED and the Sylvania Lightify bulb. I found that the Cree Connected LED did not help my situation, but that the Sylvania Lightify bulb did, very well. This leads me to believe that the Sylvania Lightify bulb does relay (though it does not state such in their documentation, that I could find.)
To be fair, the Cree bulb also did not state anywhere that it would repeat.
Both bulbs, work great as bulbs, so are a good purchase for such.
The Sylvania bulb I bought is here

Unfortunately, although the Sylvania/Osram bulbs do repeat, they have a known problem where when the network is busy, they get a kind of “buffer overflow“ situation which causes them to lose some of the messages they are supposed to repeat. This is mentioned in the official supportbase article on those bulbs. Whether you will run into the problem or not just depends on how busy your network gets.


Note: SYLVANIA bulbs have a known firmware issue that can occasionally cause them to fail as ZigBee repeaters. This can potentially cause other ZigBee devices to fail to update and/or respond.

You can read more about zigbee bulbs as repeaters in the following FAQ (this is a clickable link)

Hi @JDRoberts,
I’ve been wrecking my head as to why my Zigbee devices keep dropping off and finally i think i can see it might be this issue!! Did a quick calculation on the IDE and definitely over 32 devices. When you consider that the Sengled Bulbs identify as end devices as well as a lot of zigbee Smartthings Sensors and some Xiaomi Sensors then everything starts to make sense.

I have orders a Zigbee 3.0 Outlet that declares its self as a repeater so excited to see if this resolves. Can you advise how you rebuilt your Zigbee Network? I’ve readsuggestions to disconnect everything for 30 mins and then reboot?

Many thanks

Yup, that’s how to do it (power down the ST hub completely). Almost all my devices are Zigbee, and that’s how I rebuild mine.

First rule of Home Automation: The model number matters

A zigbee 3.0 outlet may not help you at this time. The V3 version of the hub has some support for the 3.0, but the other hubs do not. Smartthings uses the “ZHA” ( zigbee home automation) profile instead. Although the Zigbee 3.0 devices generally will also work with ZHA, not all do. So it just depends on the specific brand and model that you purchased. (first rule of home automation: the model number matters.)

In addition, the Xioami devices are only intended to be used with their own gateway, and are not 100% compliant with the specification.

Setting aside the Xioami devices for a moment, Pretty much any mains powered device will act as a repeater. For zigbee with SmartThings, that usually means either plug-in pocket sockets or lightbulbs other than the Sengled bulbs. But light switches, in wall receptacles, and wall micros, and plug-in sensors should typically also repeat.

One of the best zigbee repeaters at this time is also one of the least expensive: IKEA Tradfri

The simplest and most reliable at this point (April 2019), which also happens to work well with the Xioami devices, are the IKEA Tradfri Plug-in module and their smart bulbs. (The handheld buttons and remotes have only partial integration with SmartThings and don’t work as repeaters anyway, since battery powered devices do not repeat.)

Those are available in most countries, and are quite inexpensive, so I would recommend starting with those. ( The product description will say that it needs its own gateway, but you can use the smartthings hub instead.)

Rebuilding your network after you add a new repeater

As far as rebuilding a zigbee network with smartthings, that’s easy. That’s called a “heal.“ leave all of your other devices on power, but unplug the hub (including taking out any batteries) and leave the hub off of power for about 20 minutes. This will cause the other devices to go into “panic mode.“ Then when you put the hub back on power, all the individual devices will rebuild their neighbor tables. This can take a little while so you might not see improvements until the next day.

More Details

The following two FAQs should help you understand this better. Start with post 11 in the following thread, read that, then go back up to the top and read the whole thread. (The topic title is a clickable link)

And for more details specifically about repeaters, read the following:



FYI: The IKEA TRÅDFRI Control outlet is in fact a certified ZigBee 3.0 device.

Also, according to a SmartThings FAQ, the 2018 (v3) and Wifi SmartThings Hubs support ZigBee 3.0, but when used other hubs, ZigBee 3.0 devices are backwards-compatible:

Does the SmartThings Hub work with Zigbee 3.0 devices?

The newest generation of the SmartThings Hub (2018) and SmartThings Wifi support Zigbee 3.0. Zigbee 3.0 is backwards compatible, which means that Zigbee 3.0 devices can connect to other versions of the SmartThings Hub - such as Samsung Connect Home, Hub v2 (2015), and Hub v1 (2013) - but these other versions of the Hub do not support QR code onboarding.

If this is not true then they should revise their FAQ text…

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It’s true, it’s just not complete. This has been typical of the smartthings documentation all along. Remember when you could add a smartlock but you couldn’t change the user codes without a custom app? Or the fact that the hub is a certified zwave plus controller but has no support for central scenes? (Again, you have to use custom code.) Heck, you have to use custom code just to set associations.

Or how about when it was a certified zigbee ZHA coordinator but didn’t support any group commands?

They have been adding zigbee 3.0 support To the newer hubs, but that doesn’t mean that every zigbee 3.0 device will work with it for all features in the specification.

One obvious issue which is allowed but not called out is that you can’t do touchlink commissioning. In contrast, the hue bridge does.

So again, it will work with some zigbee 3.0 devices, but not necessarily all. If it’s not part of the “works with smartthings“ certification program, you just have to try it and see. :sunglasses:

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Why is this information not readily available in all of the product specs? I have about 108 devices connected to my zigbee network and am looking to add more all the time. I would much rather purchase a device that’s sole job is to repeat zigbee and supports a TON number wise of devices and is easy to use (xbee does not look easy). This is literally the only thread on the internet that actually details how many devices can be repeated by a specific device and unfortunately the best one (iris) is no longer available. Does the new GP-U999SJVLDAA ST outlet support more then the 6 repeated devices of the old version? If you google around you’ll find the only qualifier people give for zigbee repeating devices is if it’s “good or not” and that doesn’t help at all. I need real factual numbers. I have a smart home, not a smart room and I need hardware to support it. Sorry, been at this search for hours now and everything I’ve found leads to a dead end and it’s wicked frustrating. Thank you very much to Ankurg09 for the info, just wish there was more up to date information. /rant

I don’t think that information has been shared officially, so I’d love to see if it it has. But in my experience using the 2018 SmartThings outlet, I’ve seen it with as many as 11 children before, which is quite a lof compared to many of my other repeaters (I’ve only seen the Xbee with more–XCTU tells you, I think, but I think some support something like 13 or 14). Something like the 6 devices you saw with the older version of the ST outlet is pretty typical for most Zigbee repeaters.

I’m not sure what people mean when they say “good,” but there are certainly multiple critera to consider. Number of child devices supported is certainly one, but others may have different criteria like size of the device, signal srength, and price, in addition to others like reliability. And since you emphasized “house” and not “room,” you may get better use out of multiple repeaters even if they only support smaller numbers of children as opposed to one repeater like the 2018 ST outlet that appears to support quite a few (example: Tradfri outlets are cheap but a bit bulky, but if you don’t care or able to hide them somewhere less visible, that may make them “good” for you–you could get 3 or 4 for the price of one ST outlet; the Tradfri USB-powered repeater is also just a repeater [and optionally charger] but I don’t know how many children it supports, and it might have a weaker radio than some others, but this isn’t necessarily bad).

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