Z-Wave: Ring Alarm Extender Gen 2. They have 700 series chips and Bernal battery backup. They also report power events (switch to mains, switch to battery) so you can power fail detect and do clean shutdown on your hub before UPS fails using an appropriate rule.
Note that, when power returns, the Ring will power up before the hub reboots, so the return to mains power event is missed by the hub. Solution is to have a SystemStart() rule that refreshes the power state of the Ring extenders.
I agree. I think, for my house, I am getting better range with Zigbee.
I've only used the Aeotecs, but they've been great. Set 'em up, pick the places you want to put 'em in, plug in, done (well, wait a few days for the network to reconfigure, then done).
Look up the normal shutdown and failure temperatures of a COMPUTER or SERVER. It is much lower, and is a better comparison of what this device is.
My C4 hub runs at 75C internally in a 23.5 DegC room... If you assume the delta stays perfectly constant (it wouldn't, but OK...) then it would die WELL before 70F ambient temperatures (assuming the CPU has a very standard 90C max operating temp) - at probably more like 38-39 DegC. The C7 seems to run cooler internally though, so maybe it would survive - who knows? Just as a data point, my development C7 thermally locks up sitting on a luke warm (<48C) network switch (I checked it with a temperature gun)... 
I would put $20 of my own money on the table right now that a production hub with devices paired and logic running on the hub will thermally lockup well before 70C ambient temperatures. Likely closer to 40C ambient than 70C...
The device wouldn't be DESTROYED at 70C, but it wouldn't RUN... But by all means, put YOUR hubs in the attic. Hope it works out for you.
I know one hub that would lock up regularly in a 75F room, Stopped doing it when it was repositioned to be upside-down (vent holes on top). This particular hub died before the endpoint indicating operating temp was known to me, so I don't know how hot it got ....
Yeah.... I think the thermal design of the hub is really marginal. It obviously works, but it isn't great.
The internal temp is very dependent on CPU load (which makes sense). I can drive my dev C7 (which runs 20+ DegC cooler than my C4) to temps of 70 DegC+ if I get the CPU cranked up via bad code or a loop.
As it is not actively cooled, it simply can't dissipate the heat fast enough if the CPU is actually working.
AKA the thermal design is NOT rated for full CPU load even at typical room temperatures. Put it in a hotter environment and you have even less headroom before it gets into heat exhaustion.
I will say that a fan blowing on the device would greatly extend its ambient temperature operating range, though.
The hub I referred used about 30-40 LiFX bulbs, of which ~10-15 were unreachable at any point of time because switches were manually turned off.
I have never found a spec sheet for the amlogic S905W cpu (just looked again, still couldn't find it), but anecdotally I'll say that a lot of people with X96 Mini boxes (more or less the same as our Hubitat hub but w/o "z" radio add-on) complain about overheating and hub lockups under high CPU load, too... At normal room temperature.
With the C5 and C7 running so much cooler than the C4, maybe the design changed along the way... Or maybe they slapped a better heatsink on it? Not sure, and I'm too lazy to go investigate.
Maybe @gopher.ny knows why the C4 runs 25C+ hotter at idle than the C5 or C7?
second recommendation for the ring zwave repeaters over the aeotec ones. I have both and I find the ring ones are much better (battery backup), and in practice I find they have better range and devices seem to want to use them over the aeotec.
That happened to me too - had a C-5 sitting on top of a Sonos Connect - smooth glossy plastic surface - had a lot of issues. Flipping the hub over seemed to resolve the problem until I was able to relocate it to a more temp friendly area.
Yup, the ring are good. It doesn't take many of them, either.
I got them on sale so have 6 of them. 1 has 20 devices repeating through it (the one that is about 10 ft from the hub), the other 5 are doing almost nothing - 3 have one device repeating through them and 2 have zero.
This is the only thing I could find...
Zigbee seems to travel far better than zwave in my experience, you may not need one in each room but the bigger the better with with the mesh
As for the the temp debate going on, I had a hub that kept turning off, it was in a server room which was 28 degrees Celsius, we went through various trouble shooting and it turned out that the test was too high, Bobby at Hubitat helped out with this
I have a lot of items! Too many but all my items are budget items lol
There are 3D printer wall mounts and shelf stand mounts for the Hubitat Elevation on thingiverse.com, posted by community members. Makes cooling easier.
There are a couple of related threads in the forum from about a year or so ago.
You are being too kind. I don't really see any evidence of thermal design. A small hole or slot above the processor would at least offer a bit of convection. My C7 must be lightly loaded, as I have yet to see it get 15C over ambient.
My C5 hub that has no devices or apps idles at 17C over ambient. Now, that is the CPU temp, not the 'box temp'. I'm sure the device on average is lower.
Download the Hubitat app
