Hubitat C-8 works only with provided power supply and no other USB-C power supplies

Has anyone else noticed that the C-8 powers on only with the supplied block + USB-A-to-USB-C power cable, and that no other power cables work? I have an existing, nearby USB-C power supply. It has powered everything from my iPhone to my MacBook Pro (so plenty of power). But when I plug a USB-C-to-USB-C cable into it and the C-8, the C-8 never powers on. I let it sit a full minute—no light. So I tried various combinations of various USB-C bricks and cables, and nothing. The only thing that works is the included brick with the included cable. That ... doesn't seem normal? ... or spec-compliant?

(The exception is that I can get it to power on with POE-to-USB-C splitters, but then my Z-wave radio doesn't work, so that's a moot exception.)

Mine is currently being powered by an old 1A iPhone PS, and probably the cord that came with the C8 it but cannot be certain of that. Those old iPhone bricks are great.

I think I used the included C8 PS for my old C7 when it got demoted to bench testing and code development.

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Sounds like what you have in common is USB-C to USB-C, not just the fact that you were using the supplied power supply and cable. I have no problem using a different USB-A power supply with (of course) a USB-A to USB-C power cable, not that I'm advocating for using anything besides what came in the box. :slight_smile:

I think the problem is with USB-C on the power supply end. I assume the reasoning is that USB-C requires negotiation, whereas USB-A is always spec'd to supply at least a little power (with more possible via negotiation, or apparently the need to do this was widely ignored in implementation, at least as long as it's 5V). You will likely have a similar issue with many similar small electronic devices that assume the simpler reality of USB-A power, as the C-8 appears to also do.


I have no doubt that's the case, but that's kinda my point. Why did C-8 introduce USB-C if it's not going to be a USB-C-compliant port capable of negotiating for USB-C power? Why not just stick with USB-A?

Because the old micro-usb connector is obsolete (and garbage) and everything is phasing it out including small electronics.


Not to be pedantic, but the C-5/C-7 used micro-B, not A, as the power supply connector. Early hub models did have USB-A, but this is normally used on the "host" end (exactly as it was on those for connecting radios).

As for the answer to the question, I can only assume it is related to some combination of the manufacturer substantially re-using the existing design/specifications, just with a different connector (pretty common USB-A/USB-C issue; Reddit and Google search results are full of questions and answers on this) and the cost that would be involved to change.

Regardless, I agree with the above that the connector just works better physically, besides becoming more and more common nowadays, so I'm happy. :slight_smile:


I'm using one with no Z-Wave issues. If interested, this is what I'm using -

DSLRKIT Gigabit USB Type C Active PoE Splitter 48V to 5V IEEE802.3af Power Over Ethernet for Raspberry Pi 4 4B




Fixed, thanks. :smiley:

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USB-c only needs negotiation for greater than 5V draw. Otherwise devices power with 5v (as a safe fallback). I haven’t seen that issue, mine is powered by a 5 port anker 40w “hub”. I have had PoE issues that I’m still chasing.

I would make sure the usb-c connection to the hub is “clicked” in.

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@beamerblvd On my backup c8 I'm using an apple USB-C block and a no name usb-c to usb-c cable to power it and it's fine. As stated above, the power draw is 5v and doesn't have any sort of issues. (On my production C* hub I use a poe splitter, but I use cisco switches not unifi)

Not quite. USB-C does not deliver power until something is plugged in. There's no active negotiation to get 5V, but you need particular resistors to signal to the other side that a device is present and would like power. There are a lot of USB-C devices that don't have the appropriate resistors... and consequently work fine with A-to-C cables (since A always supplies power) but are DOA with a C-to-C cable.

It's a particular problem with adapters to connect a USB-C charger to a micro-B port; the adapter should provide the appropriate resistor, but most don't.


Sorry for the missed piece. Yeah, I mean that C defaults to 5v and requires negotiation to go higher. It’s also how A-C cables “just work” with 5v.

Thanks for the clarification.

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I bought a Konnected battery just for the C-8 during power outages. But it doesn't power the hub at all. I got some different cables to go from the 2.5mm port to the C-8, to no avail.

After ordering a $60 standard UPS for satisfaction [mumble/grumble], I stumbled upon a BIX USB DC to DC power converter. I think this device would let the Konnected battery power the C-8, but until I find another use for the Konnected battery I'm not in any hurry to find out. It alone is also $60


Should any of that be useful to anyone else. . .

...bob t

I thought I would mention that I was able to power the C-8 Pro from a USB C PD charger although the same charger and cable did not work for the C-8 non-pro. For a few minutes I thought my C-8 had suddenly died.

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I had the exact same experience! I used an Apple 67W USB-C charger to power up my new C8 Pro hub on the workbench when I received it. I then swapped it out for the C8 hub it was replacing, which is using a PoE splitter powered by my UniFi switch. The C8 Pro powered up fine on the PoE splitter, however the old C8 hub refused to power up using the Apple PD USB C charger. For a minute there, I thought I had fried the C8. I then powered it up using the Hubitat provided USB C power supply and it came right up.


3 posts were split to a new topic: [2.3.8] Soft reset causes boot failure

My C8 is plugged in with some random cable to the USB-A port on the front of my CyberPower UPS (which is powered off the UPS battery). Says 2.1A on the port.


Same here.

As of today I’ve replaced the C8 with a C8-Pro, still happily plugged into the front USB on my UPS. Looks like whatever increase in power the C8-Pro might have is still within what the UPS can provide.

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