I'm writing this post to help others avoid a few mistakes that can negatively impact their experience with the C8 series. The first major gotcha I ran into was connecting USB-C power. I found that the Z-Wave modem built into the C8 can enter a state of high intermittent failure based on the power supply. Unless you have a bad Z-Wave device disturbing your network, be very careful how you power your C8.
The original power supply was a good start, but I wanted to reduce cables and supply power over PoE. I purchased several PoE/USB-C adapters from Amazon, and while they all appeared to work well for hours or even days, the Z-Wave modem would suddenly start failing for no apparent reason.
After months of trial and error, I finally narrowed down the problem by A/B testing different power supplies. I currently use an APC battery with USB-A ports to provide clean power to the C8, and the Z-Wave modem has been stable for over two months.
Moral of the story: if your Z-Wave network is acting up, try A/B testing the power supply to the C8 as part of your debugging plan.
Next issue: Yale locks with 500 series Z-Wave chipsets only support S0 security, which is chatty and can cause performance problems on Hubitat C7 and C8 hubs. Because locks cannot be connected without security, I replaced the 500 series chipsets with 700 series upgrade modules that support S2 security. This significantly improved Z-Wave network performance and reduced scene change lag.
To reduce the processing load on your Hubitat hub, only use unsecure Z-Wave connections or S2 secure connections whenever possible.
Hope this helps reduce headaches for other.
Nice write-up. Several other people have had issues with PoE.
That is a great summary. I would add; not use security unless there is no other choice. Almost all devices can work without security.
True, the super majority of zwave devices I've encountered do appear to have the ability to function without any security requirement. I've avoided that part of the discussion because I feel security overall is a personal choice and best left for a different discussion. I have 78+ Zwave devices with only 5 of them set to S2 security. overall Zwave network has been responsive and reliable in this configuration and as such I've avoided any changes. I do wonder through how the Hubitat C8 would handle a pure S2 Z wave network but haven't take them time to A/B test such a setup as it would require significant amount of setup work. I'm lucky because I live in the suburbs and my chances of encountering a bad actor are probably less then that of those living in a city. Ops, went a bit far from my original topics of reliability and into security. don't want to blend those topics. my bad.
Just to confirm, is your poe switch Unifi?
I found this awhile back. I'll post it here in case anybody has lost their original power supply and needs a high quality replacement. Mostly helpful for UK folks.
That was true for the launch C7, but with the current state of Z-wave I think that is debatable. S2 will guarantee better transmission error checking and a few users have proven that to be effective on some sensor devices that were otherwise getting bad values. Bad values were probably from corrupted zwave messages, since the S2 fixed it.
I look forward to testing that. I have found that switches do not really need security so 'no security' is good for them.
I used to be a "S2 meh" guy, but I've come around to @jtp10181's line of thinking -- last spring, I switched everything I could over to S2. I still have four irreplaceable 500-series devices that can't do it, but I like the peace-of-mind with the beefier error-checking, especially with a few of my devices that drop down to 40kbs every now & then.
One thing that held me back earlier was firmware updates, but I figured that out for Zooz (and I'm confident that process would work for other manus), so now I'm all in on S2.
That guy who runs that website is amazing. Extremely detailed testing
I got most all my chargers based on his recommendation, and they all are still serving me well years later
I use POE extensively. I run an old Cisco 2960x 48 port with 750 watts of total power. After buying many cheap POE adapters I realized many of the cheaper adapters do not supply enough current and some adapters will not let data through unless the power side is being used. Aliexpress is full of cheap junk adapters that will cause problems with any draw over 300mA. Your hub will be perfectly fine at idle, but as soon as the draw ramps up it can cause the hub to crash or lockup. The USB power monitors are very useful here in determining how much power the adapters are capable of delivering.
example:
https://www.aliexpress.us/item/3256804614339206.html?spm=a2g0o.order_list.order_list_main.94.97bd1802rnmVCb&gatewayAdapt=glo2usa
Or the super deluxe model that supports PD and USB C ( was $12.00 when i Purchased in 2020 ! )
https://www.aliexpress.us/item/2251832867042370.html?spm=a2g0o.productlist.main.1.24a85d3aC8CtWd&algo_pvid=796cfd6a-4fa7-4be7-82f7-cfcfc79defbc&algo_exp_id=796cfd6a-4fa7-4be7-82f7-cfcfc79defbc-0&pdp_npi=4%40dis!USD!24.45!19.56!!!24.45!!%402103225116969047067757812e4ba8!67482537135!sea!US!712076553!&curPageLogUid=w1KXeg8M2t0y
The main issue seems to be POE adapters on the C8 when using a Unifi switch. Other switches with the poe adapters and the c8 don't have a problem.
Yes, the PoE switch is a Unifi USW-48-POE (195W) with a current load of 51W so well below the rated max of 195W.
I'm curious to know now much more processing power the C8 may have over the C7 when it comes to the Z wave encryption workload. I had a C7 at one point with all devices using a level of security. The reliability was hit or miss and near impossible to narrow down root cause. Hence the migration to the C8 with as little security enabled as possible to try to reduce workload and keep things as simple as possible to start.
so far, my best results were the build in USB ports on APC batteries. They are battery backed up and have provided the most stable result encountered thus far. Anker power supplies have also worked well for me but I've done very limited testing and would say to be 100% confident in Anker I'd want to run longer sample times.
Not the issue. Pretty much every time people with c8's had the z-wave problem with poe splitters it was because it was on a unifi switch. I run Catalyst 3700's and it's fine. Hooked up my one unifi poe switch and z-wave went to hell.
I never got a crash. The C8 was always running, it could always reboot which was the odd part. I expected the PoE to crash the C8 but it never did. All I ever got was a large scale failure of the Zwave network while my Zigbee devices appears to continue to work normally. The PoE adapters I purchased off of Amazon also run my raspberry Pi's with no problem which gave me the intial trust and probably why I didn't suspect the PoE for so long. I assuming the raspberry PI which a M.2 memory stick had to be drawing more power then the C8 ever would. To add to that, I did place a USB-C power monitor C8 and checked for basic voltage fluctuation or amp draw issues but couldn't find any that were obvious. I did try several other random USB chargers I have lying around the house but that provided mixed results. For now, staying with a very high quality power supply and USB -C cable appear to have resolved the issue. Long term, it would be nice to get a high quality PoE adapter that could do that job so I can more centrally location the C8 but I've been unsuccessful finding any that give me confidence in a better result.
I power a lot of WAP and RING cameras with the Unifi switch and have never had an issue with it. It's also well below it's max power draw and it's on a APC UPS battery for surge protection and power conditioning. I don't have enough evidence to say Unifi switches are better/worse/same in the PoE category in comparison to Cisco, Juniper or other. I do have decades of experience deploying Juniper, Cisco and Arista in large scale content delivery companies and I can say with great confidence those major brands all have their own unique issues and I wouldn't say any one of them is any better then the other overall. Unifi's hardware in my experience has given me the same level of quality as say an Juniper EX3300 class, the Cisco 29xx lines or the Arista 700 series. But again they each of different issue without any one really winning in my opinion in that category.
It's only with the C8... It seems the combo creates some kind of interference the c8 z-wave radio doesn't like.... It's been confirmed to be a problem. It's not a problem with the c5 or c7
