5 ms·

9v or 12v over USB-A is reasonably common here in Asia... You always need to check the voltage rating before randomly plugging stuff in if it isn't from a b

9v or 12v over USB-A is reasonably common here in Asia... You always need to check the voltage rating before randomly plugging stuff in if it isn't from a big manufacturer. For example, the handwarmers I'm using right now are USB-A at 12 volts, but have a dial to adjust the voltage up and down between 0 volts and 12 volts to adjust the temperature (I think it's actually PWM on the 12v power lines, but haven't actually checked). 5.5V or 6V is also common because it lets you use thin cheap wires which remove about a volt and still can fast charge phones (which tend to be picky and will drop back to 500mA charging if the voltage droops). Big manufacturers also use non-5V over USB sometimes, but you need to send a special message to enable higher voltages, so it's safe to plug them into anything. Still troublesome if you're using a USB Y-splitter or multi-headeded cable.

rahimnathwani 3y ago
Where in Asia? I lived in China from 2010 to 2019 and the only voltages I've seen on USB A ports is ~5V and ~4.2V. The latter on the charger for some rechargable bicycle lights.
- londons_explore 3y ago
  Thailand
  - berkes 3y ago
    > Thailand > USB-powered handwarmers This combination is just weird. So weird, that the only place I can think this then applies, is... Thailand.
    - exadeci 3y ago
      Tourists only go to the beach areas, north has mountains and can be quite cold
      - berkes 3y ago
        I know (I have family there, and near the beaches). But "cold" is relative. I've had temps as low as 14℃ (57F) in Chiang Rai, Pai and near Udon Thani. And while that may be "freezing" to people used to tropical climates, that's shorts-and-terrace-outdoor-yay temps where I'm from (North Western Europe). I found it alienating to see people with woolen hats, mittens, thick jackets and scarves in Thailand, when for me the temps were T-Shirt and shorts grade. edit: Though, reversed, another alienating sight was a kiosk with Thai Takeaway on a parking lot in Åre ("north-Sweden, south-lapland) under 2m snow and ice with outside temps of -18℃.
NotYourLawyer 3y ago
That’s terrible. Why don’t they just use a barrel plug?
- londons_explore 3y ago
  There's lots of those too - and converters from USB to barrel (of various sizes) and vice versa. The only thing that is truly standard is the polarity of power on a USB-A plug.
- Workaccount2 3y ago
  Because it's cheap and easy to implement into designs. No need to spec and use a new part, just use USB-A for all power connections across everything you sell.
- pixl97 3y ago
  Not that barrel plugs are any better... I wish I would have wrote the model down posterity, but at one point I worked a trading company and a number of the users had ISDN at home. There were two 'different' modems, and I say different because only the model number on them notified you of it. One had a plug that output DC power. One had a plug that output AC power. They were the same size wall wart. Same size barrel. But if you plugged the AC adapter in to the DC modem it would make a noise like you curled the modem up into a ball and let the magic smoke out.
  - ToucanLoucan 3y ago
    Semi-related: My wife has the little Fallout 4 fridge they dropped a while back, not a proper fridge but one of those peltier plate ones that's only really good for like, soda and beer. She was quite upset when it died one day and I toss it on the bench, and stab the power socket with my alligator clips and give it 9 volts. Worked perfectly so it just needed a new power supply. A quick Amazon order, snip the wire off the old, splice it to the new and a little soldering/heatshrink later and we're back in business. Plug it in and... nothing. Turns out, the original power supply had it's polarity reversed. So then I opened the fridge and swapped the connections on the backside of the socket because it was less fuck-about than re-splicing the wire. Fortunately a few confused minutes of reversed polarity didn't damage anything (not that there's really anything to damage, it's a peltier plate and a fan) Genuinely, why? The standards make things easier. Why go out of your way to not use them?
izacus 3y ago
This is absolutely cursed.

rahimnathwani 3y ago

Where in Asia? I lived in China from 2010 to 2019 and the only voltages I've seen on USB A ports is ~5V and ~4.2V. The latter on the charger for some rechargable bicycle lights.

londons_explore 3y ago
Thailand
- berkes 3y ago
  > Thailand > USB-powered handwarmers This combination is just weird. So weird, that the only place I can think this then applies, is... Thailand.
  - exadeci 3y ago
    Tourists only go to the beach areas, north has mountains and can be quite cold
    - berkes 3y ago
      I know (I have family there, and near the beaches). But "cold" is relative. I've had temps as low as 14℃ (57F) in Chiang Rai, Pai and near Udon Thani. And while that may be "freezing" to people used to tropical climates, that's shorts-and-terrace-outdoor-yay temps where I'm from (North Western Europe). I found it alienating to see people with woolen hats, mittens, thick jackets and scarves in Thailand, when for me the temps were T-Shirt and shorts grade. edit: Though, reversed, another alienating sight was a kiosk with Thai Takeaway on a parking lot in Åre ("north-Sweden, south-lapland) under 2m snow and ice with outside temps of -18℃.

NotYourLawyer 3y ago

That’s terrible. Why don’t they just use a barrel plug?

londons_explore 3y ago
There's lots of those too - and converters from USB to barrel (of various sizes) and vice versa. The only thing that is truly standard is the polarity of power on a USB-A plug.
Workaccount2 3y ago
Because it's cheap and easy to implement into designs. No need to spec and use a new part, just use USB-A for all power connections across everything you sell.
pixl97 3y ago
Not that barrel plugs are any better... I wish I would have wrote the model down posterity, but at one point I worked a trading company and a number of the users had ISDN at home. There were two 'different' modems, and I say different because only the model number on them notified you of it. One had a plug that output DC power. One had a plug that output AC power. They were the same size wall wart. Same size barrel. But if you plugged the AC adapter in to the DC modem it would make a noise like you curled the modem up into a ball and let the magic smoke out.
- ToucanLoucan 3y ago
  Semi-related: My wife has the little Fallout 4 fridge they dropped a while back, not a proper fridge but one of those peltier plate ones that's only really good for like, soda and beer. She was quite upset when it died one day and I toss it on the bench, and stab the power socket with my alligator clips and give it 9 volts. Worked perfectly so it just needed a new power supply. A quick Amazon order, snip the wire off the old, splice it to the new and a little soldering/heatshrink later and we're back in business. Plug it in and... nothing. Turns out, the original power supply had it's polarity reversed. So then I opened the fridge and swapped the connections on the backside of the socket because it was less fuck-about than re-splicing the wire. Fortunately a few confused minutes of reversed polarity didn't damage anything (not that there's really anything to damage, it's a peltier plate and a fan) Genuinely, why? The standards make things easier. Why go out of your way to not use them?

izacus 3y ago

This is absolutely cursed.