3 ms·

AC outlets have been the same on a per-country basis for decades and will be for several more decades. USB, on the other hand, is "hey I have a new plug" every

by dheera 3y ago

AC outlets have been the same on a per-country basis for decades and will be for several more decades. USB, on the other hand, is "hey I have a new plug" every 5 years. We'll have USB-D in 2030 and everyone will have to buy new cables and adapters. Anyone who needs 40V should just design it to use 120V/240V instead.

lxgr 3y ago
Sure, but what makes 20V the perfect voltage for almost everything, so important that we should go through the effort of rewiring entire buildings? It's way too much to charge small accessories (without an internal step-down converter [1]), yet it's probably not enough to sustain (let alone charge) beefy laptops. > "hey I have a new plug" You do realize that this is exactly your pitch for these 20V "standardized" plugs/outlets, right? :) [1] A big reason why USB's 5V is so popular is that it's just the right voltage to charge lithium ion batteries and run simple circuits without expensive (in terms of parts) active voltage converters.
- dheera 3y ago
  > it's just the right voltage to charge lithium ion batteries No, it's not. Lithium is nominally 3.7 volts per cell and charging voltage goes up to about 4.2 volts max, maybe 4.3. Definitely never 5V. A 5V->4.2V buck converter isn't particularly different than a 20V->4.2V buck converter. In fact it's probably a bit easier to make a 20V->4.2V converter since you don't have to worry about parasitic losses as much. > You do realize that this is exactly your pitch for these 20V "standardized" plugs/outlets, right? :) Not exactly, (a) I'd use an existing connector, maybe a Lenovo 20V connector (b) USB keeps having to switch things because they weren't a charging standard to begin with, they were abused as a power plug and then had to keep evolving with that while maintaining backward compatibility and continually keeping up with Moore's law in bandwidth requirements. A 20VDC plug would just be that -- a low-voltage socket for <100W appliances. Anything higher, just use 120V/240V and get upto 1800W.

by dheera 3y ago

lxgr 3y ago

Sure, but what makes 20V the perfect voltage for almost everything, so important that we should go through the effort of rewiring entire buildings? It's way too much to charge small accessories (without an internal step-down converter [1]), yet it's probably not enough to sustain (let alone charge) beefy laptops. > "hey I have a new plug" You do realize that this is exactly your pitch for these 20V "standardized" plugs/outlets, right? :) [1] A big reason why USB's 5V is so popular is that it's just the right voltage to charge lithium ion batteries and run simple circuits without expensive (in terms of parts) active voltage converters.

dheera 3y ago
> it's just the right voltage to charge lithium ion batteries No, it's not. Lithium is nominally 3.7 volts per cell and charging voltage goes up to about 4.2 volts max, maybe 4.3. Definitely never 5V. A 5V->4.2V buck converter isn't particularly different than a 20V->4.2V buck converter. In fact it's probably a bit easier to make a 20V->4.2V converter since you don't have to worry about parasitic losses as much. > You do realize that this is exactly your pitch for these 20V "standardized" plugs/outlets, right? :) Not exactly, (a) I'd use an existing connector, maybe a Lenovo 20V connector (b) USB keeps having to switch things because they weren't a charging standard to begin with, they were abused as a power plug and then had to keep evolving with that while maintaining backward compatibility and continually keeping up with Moore's law in bandwidth requirements. A 20VDC plug would just be that -- a low-voltage socket for <100W appliances. Anything higher, just use 120V/240V and get upto 1800W.