They are actually headlights. The kind that strap to your head, which I happen to use for cycling. I suppose they were intended for joggers. I don’t know the makes but it’s two different manufactures, likely some cheap chinese stuff. One is an LED strip across the forehead with a side beam, 7 or so different functions with different colors and intensities. The other has selectable red, white, or yellow colors, blinking or solid.

kenwood cr-st90s. Not sure about the OEM charger since I don’t have it.

The seller had a few of these same radios, new in box, but all missing the chargers. My thought was either the seller sold them separately or the chargers were stolen and so whatever retail store had them could not sell them and they ended up on the street market. But after seeing that the OEM chargers are strictly 9v, they seem worthless without the radio. Unless it’s just a shitty label. Maybe the OEM charger is proper USB PD, but they only wrote 9v on the label. I can only speculate.

The universal charger I have could also be dodgy. It was from a 2nd-hand shop. But afaik it’s fine.

Since I don’t have the OEM charger, I cannot see how it is marked. I just recall it was only marked 9v.

(edit) it’s also possible that the OEM chargers are poor quality and have short lives… maybe the retailer opened boxes just to replace broken chargers for customers under warranty, which would also result in radios without chargers.

Dead battery was my 1st theory, but it’s questionable. I fiddled with a healthy demo unit (same model) at the store. The battery ran out of juice and the machine shut down. I plugged it in and hit the power button and it instantly turned on. So it can apparently run directly off the USB-C as the battery charges (and the manual says as much). But the one I have never powers on, even when connected to power.

voltage = current × resistance, IIRC my high school physics correctly. If current is zero, then voltage must also be zero, no? I don’t understand how voltage can be positive if amperage is zero.

Is the spec ambiguous on that then? Is a 5v default and a PSU without default both compliant?

USB-C chargers won’t work in this case, as they only output voltage, if they detect a device.

Note that the first 2 times I attached a universal USB-C charger to the radio, it gave a charging animation (though after ~30-45 min wait). So I am struggling to work out how that happened. Did the charger give up after waiting a long time and say “fuck it, will give some arbitrary power”?

You need a USB-A charger with a A-to-C-cable.

My universal charger has both USB-A and USB-C ports. I tried the USB-C port first (thus usb-c→usb-c). Then at one point I tried usb-a→usb-c. I was expecting usb-A to behave the same because the charger specifies the same range of voltages for both ports. The only difference is the max current is a little higher on the usb-c.

What would be the meaning of a default voltage then? My understanding of USB PD is that 5v is a default, which I took to mean it would deliver 5v in the absence of a handshake.