240W USB-C PD chargers are nearly here, says Framework CEO

The size of these kinds of high wattage passively cooled power adapters is dictated less by component density and more by what you can spread and dissipate through the enclosure with safe touch temperatures.

Last time I looked at the comms protocol, it seemed possible to request up to 10 amps. I'm not sure there's a physical spec for a matching cable, but there's also no way for a cable to communicate its current limitations.

The usb-c connector is rated to 5 Amps (A). Usb-c went up to 20V already. 5A * 20V = 100W (where we are).

We didn't want to change the connector. So we are stuck at 5A. But we can raise voltage & still have some margin. So voltage was raised to 48V. 5A * 48V = 240W.

As for raising the voltage more, it's likely very technically feasible, but probably not, for safety reasons. There are various levels of what is considered safe voltages. Higher voltages have higher ability to injure humans, to cause shock or potentially spark. Voltage is a unit of electrical potential, essentially how bad some juice is desperate to get out. 50V is the "Safe Extra Low Voltage" (SELV) limit for AC. It's actually 120V for DC but 48V/50V has a certain dislodgable-for-now mindshare. https://en.wikipedia.org/wiki/Extra-low_voltage

Connectors also have limits to their voltage isolation. If you have 1000V that electric potential really wants to get out & will arc across gaps. If there's debris or a worn connector, the threat of say 200V causing some short is much higher.

We probably could go higher. Usb-pd is super safe. When plugged in, it's in a very limited 5V state. This is a high risk moment in the connection life cycle, as pins are sliding into place, but partially connected & likely not aligned fully yet; not having any real voltage applied at this phase is a colossal design win against so so so many power delivery mechanisms in the world. Device & source _after being connected_ then have to negotiate power, on the secured connection. They ongoingly perform bounds checking to make sure the power is flowing in an expected way & will disconnect if out of spec. The connector has good isolation. 120v * 5a would be 600W and is still SELV. Add some thermal protection to the ports to make sure everything's OK there and it's probably going to just work. But any mishaps (ex: puncturing the cable, debris inside the device causing a short) would be more severe/scary. I'd love for some hackers to find out how high our connectors can go. Maybe in lab conditions we can get a usb-c connector doing a couple hundred volts fine. I would be unsurprised. Being safe for the real world though, after wear, and what happens when there is a fault is why we have SELV. But again, SELV says we could go up to 600W on this connector maybe.

One non-concern should be any additional heat, such as on cables & connectors. Since amps are still only 5A, the power loss is actually the same. Pretty great.

Yes, there exist many devices that support multiple charging rates. My phone allows the selection of 3 different wired charging speeds, as well as two different wireless charging speeds, selected in software.

Unfortunately, due to cost or incompetent engineering, most devices only accept either a few charging configurations, often just one.

I didn't realize this as my first laptop with USB-C ports could be charged with any USB charger, even a dumb 5v 500mA phone charger would eventually get the job done over a couple days. I just assumed everything was like this, but unfortunately not. A lot of laptops and cameras will refuse to draw any power at all unless they can negotiate certain configurations.

On one side, I like the idea (and I use it a lot) with USB C to power a notebook. I have a small 65W travel adapter and I can charge my beefy HP Z-Book (it even works with a 45W adapter) or my smaller Fujitsu U939. But both notebooks still have real charging ports too and normaly I use those. A real charging port are much less fragile when moving the notebook while plugged in. USB C is very fragile and it is an very, very expensive port just to load a notebook. When you use it as docking station, then, yes it makes sense, but just for charging everyday, I still much prefer a normal charging plug.