Has anyone seen any projects that involve just feeding 24v to the framework thru an expansion card? Using a less user-hostile connector standard than USB-C whose cables and accessories just break all the time?
Perhaps a barrel connector or w/e, it hardly matters.
Does the internal USB-C port require me to speak USB-PD sweetly to it or can I just give it 24V?
Many thanks, I am so tired of replacing expensive USB-C cables
24V would need some conversion, pretty much everything in the laptop is rated for 20v or less (except for the 16 but the power topology in that one is pretty unique and steps down anything higher than 20V for further use too)
You would definitely need to convince the pd controller to open up the power mux to feed it anything, the only known way (and also the easiest) to do that right now is using usb-pd. It may be possible to force open it from within the ec but since the pd controller doing that is closed source at least I don’t know how to do that.
Feeding it raw 24v is a bad idea though. While the charge controller does not care about the actual input voltage settings wise (only current is set) 24v is quite a bit above the maximum ratings of quite a lot of parts and the charge controller itself. If you wanted to do that at least feed it raw 19 or 20v not 24.
There are dc power supply to usb-c adapters to use old dell and lenovo power supplies with pd devices, maybe loot at one of those as a starting point.
Thanks so much for your fantastic reply, that is very helpful! The opposite of a USB-PD trigger board is pretty much what is needed.
And yes my dream is that the USB-PD negotiating functionality would live in the adapter, and adapter directly fed with XT30, XT60, or Anderson Powerpole, or something else… Pretty much whatever I can fit in the dimensions provided (5.5mm x 2.1mm might work but I have a visceral reaction against putting anything other than 12v on those)
I’m using a 16 with dGPU so if it were a little fatter than the adapter slot dimensions it wouldn’t hurt me, but best to avoid that if possible.
Indeed, unfortunately those are signifficantly rarer. You may need to either modify one of those charger adabters or roll something yourself using a pd phy. “simplest” setup would be a microcontroller with a pd phy and a mosfet. Offer your 20v 5a or whatever (doesn’t really matter in the case of framework as they don’t configure the charge controller to care about input voltage) via pd, if it’s selected you get 20v (open mosfet) if not you get nothing.
I kind of had an itch to make something like that since I found out they don’t configure the charge controller for input voltage you could just kook a <20V battery to it and cut out one set of conversion losses.
That’s just straight up worse than usb-c even in the durability angle, xt30 sounds like the lest bad option out of those. May even fit a non oversized expansion card.
Found this Reddit thread that has some links to reverse PD converters. But those all are more expensive than the cable replacement.
You can get a 2-meter cable for 14 EUR, is that expensive to replace once in a while?
Even using 19~20V “raw” can have risks. If a 5.5*2.1 to USB-C converter is used. The converter’s data connection might “play dumb”(depends on the manufacturer) i.e. using some resistors to negotiate the lowest PD as a attempt to improve compatibility. Unfortunately this may lead to a disaster. If the computer interprets the “dumb” resistors as 5V PD, it may open the 5V “gate” and the 19~20V will send to the 5V rail, frying the mainboard.
Nah that’s not really a problem, if it opens for charging it goes down the charge path which can handle up to 20v just fine. There isn’t a just put whatever is on this port on the 5v bus functionality. Also if it somehow interprets your 20v as a sink nothing is going to happen as there are at least 2 layers (probably more) of reverse current protection.
There is a lot that can go wrong here but that isn’t really one of them, assuming it stays under 20v (and above 0, -20v would probably also be less than optimal).
There are barrel adapters you can use to power USB C devices. Put it inside an empty expansion card and you are good to go.