21–30 of 308 posts
But the charger was always giving 12 or even 20V (i don't remember exactly, I don't have access to this device now).
A real trap.
It sound like the manufacturers just see USB-A as a convenient and cheap connector for delivering power.
I recently found a Huawei-branded power bank that outputs 9V over USB-A. See https://www.aliexpress.com/item/4000209696496.html and look at the label on the seventh picture. EDIT: I may be wrong. Apparently this is now allowed by the Quick Charge spec. See comments below.
I recently found a Huawei-branded power bank that outputs 9V over USB-A. See https://www.aliexpress.com/item/4000209696496.html and look at the label on the seventh picture. EDIT: I may be wrong. Apparently this is now allowed by the Quick Charge spec. See comments below.
My recent work experience leads me to believe CE approval is a rubber stamp. I don't have any clue what that certification is worth to anyone.
That leads to the problem child which is China and its lacking morals. Chinese companies will just slap the CE on anything, because the EU say that must and Europeans seems to enjoy seeing it. Sometimes, they will slap on a different CE marking, meaning "China Export". You can tell the difference by tracing the C to a full circle, if that hits the E exactly, its CE as in "conformité européenne", if it doesn't, it's China Export.
If you're a fly by night USB charger manufacturer, you just invent a new brand for next month, so you won't get the fines or be banned.
This is the sort of thing that almost (but not quite) pushes me to support mandatory certification (enforced by patents/other IP protections) for consumer devices that use a familiar connector like USB. Consumers shouldn’t need to worry about the specific output voltage; the presence of a USB-A connector should indicate that it abides by the specification. The hacker in me hates the idea of enforcing something like t…
I think when it comes to safety restrictions should be there. The hacker in me hates it too but just imagine if a small portion of standard-looking outlets did not output 220V (or whatever standard you have) and say 330V. Many applicances would break, or perhaps even catch fire. If there were many different USB-A devices and people were used to checking the voltage output before plugging, that might not be needed, bu…
Edit: I am not advising anyone to deliberately do stupid things, simply mentioning that from my experience the builtin margin is fairly large.
I recently found a Huawei-branded power bank that outputs 9V over USB-A. See https://www.aliexpress.com/item/4000209696496.html and look at the label on the seventh picture. EDIT: I may be wrong. Apparently this is now allowed by the Quick Charge spec. See comments below.
There are much worse things than 7V that a bad adapter can output.
One of the scariest failure modes I’ve recently learned about is a supply that still provides 5V between both pins – but 225V and 230V to ground, respectively…
To be completely fair, those power banks should have a diode (or some protection circuitry) to prevent their damage. A loose cable could easily put higher voltage on the port than 5.25V. That said, what an awful USB port to come across. A little reading wouldn't have gone amiss though. My natural reaction would have been to assume it was an output, not an input.
A diode doesn’t protect from over-voltage; that requires more complicated circuitry as far as I understand. And how would a loose cable cause a voltage spike?
Zener diodes can temporarily protect an overvoltage too but you will need something to take all that current that is now going through it, making it pretty hot and likely to fry something
You can pair something like this with a positive temperature coefficient thermistor to act as a fuse (as it gets hotter the resistance goes up).
These circuits are tricky to tune right, take up space and can add significant cost to a product. So with a drive in consumer products to lower cost smaller things you may not see them everywhere.
I recently found a Huawei-branded power bank that outputs 9V over USB-A. See https://www.aliexpress.com/item/4000209696496.html and look at the label on the seventh picture. EDIT: I may be wrong. Apparently this is now allowed by the Quick Charge spec. See comments below.
That might be within some quickcharge specs and it won't output 9v by default