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

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

#31

Is it possible for a (laptop + USB-C PD power charger) to support multiple charging rates? My Lenovo Legion 5 has a 300W charger. Caveats: (a) I'm not sure if that's input power or output power; and (b) it's not a USB-C PD connector , but my question isn't specific to this laptop. Airplane A/C power outlets aren't willing to deliver that much power. And even if I was willing to slow-charge the laptop on an airplane o…

Wouldn't airplane outlets just limit how much watts come out? I'm not an electrical engineer, I don't know much about these things, but I'd assume they have protection built-in to just cap out instead of blow a fuse if something draws too much power.

That's not really how electricity works. Wall power is a stable supply. 120v going up & down in a sine wave.

If someone is drawing 120w - 1 amp - your only control as a power source is to try to lower the voltage (voltage potential). Problem one: that will go out of spec with what devices expect, if you try to provide 80 vac instead. Problem two: switch mode power supplies that can handle sagged voltages will just try to draw more amps to get the same net power.

There's really not a good way to "cap out" power. The device just sees voltage potential (volts) and doesn't know to go lower. Blowing a fuse is the only real indicator we have.

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

#32

Is it possible for a (laptop + USB-C PD power charger) to support multiple charging rates? My Lenovo Legion 5 has a 300W charger. Caveats: (a) I'm not sure if that's input power or output power; and (b) it's not a USB-C PD connector , but my question isn't specific to this laptop. Airplane A/C power outlets aren't willing to deliver that much power. And even if I was willing to slow-charge the laptop on an airplane o…

Lenovo connectors does have resistor on center pin that indicates charger rating. So you could jerry-rig adapter cable that makes laptop think charger is lower power than it is (or just buy lower power Lenovo charger).

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

#33
post #2

It seems Gallium Nitride are quite the revolution in power density for charging equipment

Absolutely.

I think it's also super important that there is now a market of competing products too. Until recently, devices were sort of stuck using whatever the manufacturer provided. Almost no one shopped for power density. Now we have an interoperable standard & different companies can compete to be better.

USB-PD has been pretty epic so far, IMO.

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

#34
post #4

Waste heat seems like it would be a thing? Even at 95% efficiency (which is unrealistic), we're looking at a 12W heater.

Is 12W meaningful heat? I mean, I have laptops that run 10-15W and it doesn't seem like much. I guess it feels hotter because it's a much smaller surface area, but not that much (laptop heat output is mostly over the CPU/mainboard anyways)

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

#35
post #26

Is it possible for a (laptop + USB-C PD power charger) to support multiple charging rates? My Lenovo Legion 5 has a 300W charger. Caveats: (a) I'm not sure if that's input power or output power; and (b) it's not a USB-C PD connector , but my question isn't specific to this laptop. Airplane A/C power outlets aren't willing to deliver that much power. And even if I was willing to slow-charge the laptop on an airplane o…

Great ask. There's no reason devices couldn't negotiate lower power. With USB-PD, power sources offer Power Delivery Objects: different charge modes they can do. It's up to devices to pick. Right now most devices pick the highest power option (that they can handle). For a variety of reasons, it would be super sweet if we could pick lower power options! Maybe it's a multi-device charger & you want to leave more capaci…

> Very very achievable, with minimal effort.

Not with how complicated the whole stack is...

We still can't say "don't charge if other device has no AC power" even tho that info can be propagated via USB-PD...

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

#36
post #31

Earlier quoted context omitted.

Wouldn't airplane outlets just limit how much watts come out? I'm not an electrical engineer, I don't know much about these things, but I'd assume they have protection built-in to just cap out instead of blow a fuse if something draws too much power.

That's not really how electricity works. Wall power is a stable supply. 120v going up & down in a sine wave. If someone is drawing 120w - 1 amp - your only control as a power source is to try to lower the voltage (voltage potential). Problem one: that will go out of spec with what devices expect, if you try to provide 80 vac instead. Problem two: switch mode power supplies that can handle sagged voltages will just tr…

There is, just not for "AC wall voltage". It could simply drop the voltage and expect the other device to say start limiting current when it goes 5% or more below nominal voltage. Akin to how MPPT works on solar chargers

It "just" requires both sides to support that. Which won't happen as we already have USB-C if you want to negotiate the power usage.

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

#37
post #8

why was 240W picked as the upper limit for PD? Why does there even need to be an upper limit?

It’s designed around 48V and 5A. Higher voltages introduce additional risks around arcing and also get you into different safety regulations and requirements. Above 5A also starts to make cable and connector design difficult for a small connector like USB-C.

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

#38
post #26

Is it possible for a (laptop + USB-C PD power charger) to support multiple charging rates? My Lenovo Legion 5 has a 300W charger. Caveats: (a) I'm not sure if that's input power or output power; and (b) it's not a USB-C PD connector , but my question isn't specific to this laptop. Airplane A/C power outlets aren't willing to deliver that much power. And even if I was willing to slow-charge the laptop on an airplane o…

Great ask. There's no reason devices couldn't negotiate lower power. With USB-PD, power sources offer Power Delivery Objects: different charge modes they can do. It's up to devices to pick. Right now most devices pick the highest power option (that they can handle). For a variety of reasons, it would be super sweet if we could pick lower power options! Maybe it's a multi-device charger & you want to leave more capaci…

PD interposer device that can mask PDOs?

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

#39
post #8

why was 240W picked as the upper limit for PD? Why does there even need to be an upper limit?

...ohm's law ? P = U * I. Yall skipped high school physics or something?

USB cables can only get so thick. And voltages only can get so high to not be dangerous to people.

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

#40

Will be interested to see if AllThingsOnePlace reviews it, as have been following their particularly in-depth power adapter reviews and their last review[1] of a Framework charger (a 60W model) showed it performed well both in efficiency and other metrics though not the highest performer or value in its wattage range. Wouldn't ordinarily mention a Youtube channel on HN but felt their detailed testing, comparisons and…

These are exactly the kinds of channels we need more of on YT, I'm glad someone else has also found his channel.

I eagerly await more reviews of other USB-C PD chargers, e.g the 65W Lenovo ones you can get for pennies on ebay.

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