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240 watts over a USB-C connector? What next, USB toasters and coffee pots?

by Animats 4mo ago

dotancohen 4mo ago
That's only a single ampre at standard European mains voltage. It's still a lot of power for those tiny connectors and insulation, but an order of magnitude insufficient for those appliances. I bet that cable gets plenty hot at 200+ watts.
- Animats 4mo ago
  USB-C is limited to 48 VDC. Above about 50V, electrical safety codes apply.
  - dotancohen 4mo ago
    Yes, 240 watts is 5 ampres at that voltage - that's why I suspected that the cables get hot. I'm even surprised that a cable so thin is sufficiently insulated for 48 volts. I've seen 24 volt truck wiring arc out of dirty connectors.
    - seba_dos1 4mo ago
      You need a e-marked cable to get to 5A with any PD voltage, as a random crappy cable could get dangerously hot indeed. The limit is 3A and 20-21V otherwise.
  - gsich 4mo ago
    You sure? Those regulations go even higher. https://en.wikipedia.org/wiki/Extra-low_voltage https://en.wikipedia.org/wiki/Extra-low_voltage
    - exmadscientist 4mo ago
      The controlling standard is usually 62368, and the target is usually being a "Limited Power Source", which is 60V or less, and 100 VA max.
- wongarsu 4mo ago
  A full sized European electric kettle is about 2000 watts, but if you limit capacity to a single cup you can get acceptable performance on 200 watt. A USB-C coffee pot or kettle scaled to 0.2 liters (7oz) could work. Would be a great option for travel
  - deleted 4mo ago
    [deleted]
- tredre3 4mo ago
  Toasters are frequently only ~750W. That isn't an order of magnitude away from the capabilities of current USB-C. I doubt they'll ever increase the voltage beyond the current 48V (I was actually shocked that they didn't stop at 24V) so toasters are forever away. But not an order of magnitude away!
m463 4mo ago
I remember scoffing years ago at USB powered coffee warmers. Maybe the situation has changed.
- Schiendelman 4mo ago
  The Ember cups could have used PD! But the cables would have been more expensive, as would have the power brick (and you would have had bad user experiences plugging into less powerful USB power supplies)
ksec 4mo ago
I mean my electric Fan and standing lamp are both powered by USB-C. There are things that shouldn't be powered by USB-C. But there are plenty of sub 100W consumer electronics devices that really should be USB-C. I waited years before Panasonic released their lamdash shavers using USB-C.
jeffbee 4mo ago
You joke, but this is enough to make recharging an e-bike practical. E.g. https://amplerbikes.com/pages/nova https://amplerbikes.com/pages/nova
- theragra 4mo ago
  This is my dream. To reverse engineer my bikes charger and create an USB pd to take with me on a self-sustained trips.

240 watts over a USB-C connector? What next, USB toasters and coffee pots?

by Animats 4mo ago

240 watts over a USB-C connector? What next, USB toasters and coffee pots?

That's only a single ampre at standard European mains voltage. It's still a lot of power for those tiny connectors and insulation, but an order of magnitude insufficient for those appliances. I bet that cable gets plenty hot at 200+ watts.

Animats 4mo ago
USB-C is limited to 48 VDC. Above about 50V, electrical safety codes apply.
- dotancohen 4mo ago
  Yes, 240 watts is 5 ampres at that voltage - that's why I suspected that the cables get hot. I'm even surprised that a cable so thin is sufficiently insulated for 48 volts. I've seen 24 volt truck wiring arc out of dirty connectors.
  - seba_dos1 4mo ago
    You need a e-marked cable to get to 5A with any PD voltage, as a random crappy cable could get dangerously hot indeed. The limit is 3A and 20-21V otherwise.
- gsich 4mo ago
  You sure? Those regulations go even higher. https://en.wikipedia.org/wiki/Extra-low_voltage https://en.wikipedia.org/wiki/Extra-low_voltage
  - exmadscientist 4mo ago
    The controlling standard is usually 62368, and the target is usually being a "Limited Power Source", which is 60V or less, and 100 VA max.
wongarsu 4mo ago
A full sized European electric kettle is about 2000 watts, but if you limit capacity to a single cup you can get acceptable performance on 200 watt. A USB-C coffee pot or kettle scaled to 0.2 liters (7oz) could work. Would be a great option for travel
- deleted 4mo ago
  [deleted]
tredre3 4mo ago
Toasters are frequently only ~750W. That isn't an order of magnitude away from the capabilities of current USB-C. I doubt they'll ever increase the voltage beyond the current 48V (I was actually shocked that they didn't stop at 24V) so toasters are forever away. But not an order of magnitude away!

m463 4mo ago

I remember scoffing years ago at USB powered coffee warmers. Maybe the situation has changed.

Schiendelman 4mo ago
The Ember cups could have used PD! But the cables would have been more expensive, as would have the power brick (and you would have had bad user experiences plugging into less powerful USB power supplies)

ksec 4mo ago

I mean my electric Fan and standing lamp are both powered by USB-C. There are things that shouldn't be powered by USB-C. But there are plenty of sub 100W consumer electronics devices that really should be USB-C. I waited years before Panasonic released their lamdash shavers using USB-C.

jeffbee 4mo ago

You joke, but this is enough to make recharging an e-bike practical. E.g. https://amplerbikes.com/pages/nova https://amplerbikes.com/pages/nova

theragra 4mo ago
This is my dream. To reverse engineer my bikes charger and create an USB pd to take with me on a self-sustained trips.