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Otherwise it falls back to normal charge so you pay for "fast charhe" for shit… You're better off using a normal charger and not being charged for extra proprietary circuitry and firmware… fucking embedded software to manage charging…

- Cables are made of different alloy and support different maximum voltage/amperage without over-heating. And usually, manufacturers don't say shit about it. It doesn't matter for charging, slow charging preserve battery¹.

1. So fast charging sucks by design

2/n

But for direct power supply (e.g. external screen with USB C as power source), where a minimum power is required… good luck to find proper cable when you need to replace one. Unless you buy the OEM cable with is usually expensive as f*** on purpose

- No, it's not the "same cable". USB C has a shitload of different functionalities that may be supported or not, by both devices and cables. Including video¹, audio, network…

1. Whether it works well or at all between different brands is random

3/n

Cables and ports look the same, have the same name and the same fucking icon next to the port.

USB C connectors have 24 pins, 12 or each side to "symmetrical". Used pins defined what functionality can be used IF your devices has both the software/firmware and the hardware for it¹. But manufacturers won't tell shit about which pins are used/connected to the cable internally.

Cables can use 4 up to 24 pins. In practice, it's 22 pins to lower "costs", making it not so "symmetrical"

4/n

1. Devices are not publicly documented, any better than cables. Especially when it comes to video output part… In the name of "intellectual property" bullshit, a.k.a preventing people from making informed decisions as a way to enable vendor locking

5/n

Speaking of "USB C chargers and cables are universal so it's better than anything else" bullshit…

Apparently, there are manufacturers selling "dumb" USB C chargers with fixed 12 V output… What could possibly go wrong?

"Normal" users see a charger that looks-like a laptop or phone "universal" USB C charger (1), and would plug it in their phone/tablet/laptop/video LED or head/bike lights with integrated Li-ion battery with flashlight with integrated "charger" for 18650/21700 batteries…

1/4

All these devices expect 5 volts input, at first or all the time.

Depending on the used protocol. Some of them might then negociate higher voltage ONLY with compatible charger (again, specific hardware and firmware), then "gradually" (2) lower voltage (3) back to 5 volts as the the battery charge approaching the Max charging. Some protocols use 9 V as the maximum voltage.

Using fixed 12 volt USB C "charger" with anything else than the device that was shipped with/designed for, will. […]

2/4

[…] at best destroy the device. Even those than can negociate up to 12 V or more, as it still expect 5 volts at the beginning (before power/charge protocol negotiation) and at end of charging cycle…

At worst, LiPo battery might catch fire, which might lead to burning down your home, if the battery is near other stuff… which is hight likely. People dont usually charge their stuff outside, on concrete, with nothing inflammable around

3/4

So go on, it's perfectly "safe" to keep repeating to everyone and to the general public that USB C chargers and cable are "universal", out of blind fanboyism…

1. Not only nonames, but some "brands", including RPi-based laptop makers or cordless powertool makers as all.
2. Not really gradual. More like "big" steps in terms of voyage and charge percentage. Usually multiple stages, charge level/voltage combination.
3. And/or amperage back to whatever "some protocol name" specs have defined

4/4

Such chargers/power supply should be illegal…

Even technical people who would own devices shipped with such "dumb" USB C fixed 12-13 volt output, might plug them in "normal" USB C devices, by mistake.

If I had one of these crap, the first do and to put big RED labels on both the charger itself, and the USB C connector (whether it's integrated or removable/12 V rated/tested cable), with a as HUUUGE as possible warning like "12 volt only power supply/charger, strictly reserved for $deviceName"