USB-C charging

The Framework’s CPU has a maximum package TDP of 28 W [ref], and its USB-C input system has a limit of 3 A at 20 V [ref] for a maximum input power of 60 W. Any supply larger than 60 W will not give you any additional gains. I can max my CPU out on a 45 W adapter without draining the battery.

Sort of. As of 3.07 it supports setting a charge limit, however this is a fixed value. It seems that there is a way of changing this dynamically within the OS, but there is not yet a way to poll the USB-C subsystem to determine what type of adapter is present. What I want could be accomplished by manually toggling into a “don’t charge” mode that sets the charge limit to the current state of charge, but it would be much nicer if this could be done automatically when the PD source is detected as a battery bank (e.g. Dual Role capable, VID/PID list, etc.).

@Sean_Greenslade, The type-c outputs:
“The laptop will dynamically allocate 3A to 1 port, and 1.5A to the remaining 3 ports while on battery.”

The inputs don’t have an amperage limit other than the thermal fuses. @nrp correct me if I’m wrong.

@Shawn_Lewis the input is current limited and set to the negociated PD current limit allowed by the charger/power supply.
If you hard exceed the input current limit, eg by using a low wattage charger without the battery, the CPU will be throttled.

@Kieran_Levin and what counts as low? 45W?

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@Shawn_Lewis I would not recommend a power supply below 60W if not running with a battery, remember PL2 can allow the cpu to go well above 28W for seconds at a time. Plus there are plenty of things outside the CPU package consuming power, such as the NVME drive, which some models can burst to several W.

If you have 4 power hungry usb-c devices plugged in, they can consume a max of 37.5W as well.

Plus there is some regulator loss.

So depending on what you are doing, and what is plugged in I would recommend 60W to 100W.

To clarify @Sean_Greenslade post. The framework laptop supports power input of up to 20V-5A, not 3A. So the mainboard design can make use of 100W power supplies.

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Thanks for the clarification, that’s good to know.

Just want to make sure of something. Assuming I were to use at least the 60W version, would I be able to charge the laptop with an apple magsafe charger, if i were able to appropriately connect the magsafe receiver to the USB-C connector? or is the compatibility only for USB PD chargers that accommodate 60W-100W? If possible I’d like to try and design an expansion card that will use the mag safe, and control the LED

@Patrick_Shannon
I see a potential issue with this. The 60 W adapter only supplies 16.5 VDC, so it would only work with the 15 V PD level. But as it was discovered in this thread, some Framwork laptops cannot be powered from 15 V. According to Wikipedia, only the very newest 85 W MBP Retina adapters support 20 V. Assuming you want to support the earlier adapters, you might be able to stuff a very efficient buck converter into an expansion card and use the 12 V PD level. That would limit you to 60 W (12 V @ 5 A).

The 1-wire protocol to query the adapter type and set the LED shouldn’t be too difficult. There seem to be some details here.

Your circuit would also need to present the 5 V rail to the USB port during the negotiation, though the magsafe adapters supply a ~6.8 V standby rail, so that should be easy enough.

And finally, you’ll need a microcontroller to manage polling the magsafe parameters and converting them into USB-PD negotiations with the computer.

It seems doable, though definitely an intermediate to advanced-level project.

@Patrick_Shannon you are probably better off just getting hold of the magnetic tip USB-C charging cables and printing an Expansion Card to hold the receptacle semi-permanently…Which I believe has already been done and of course has native support.

@Sean_Greenslade Thanks for the detailed reply. and @andyk2 I agree this would be cumbersome to say the least, and in all likelihood I will end up using the USB-C magnetic connector options that are more readily available in the short term. But never-the-less find the idea of having my apple accessories be compatible with 3rd party products too tantalizing not to at least consider

Hey, @Shawn_Lewis, I’m having a tricky conundrum. The top-tier frame.work PC is charging just fine from my frame.work 60W charger. Even when my machine is fully loaded it’s only pulling around 45W. I want to charge my SuperTank battery from a second USB-C PD port, but I can’t get much more than 0.6W out to the external battery. Shouldn’t I be able to get at least 15w more out of the charger and into the external battery ? When I connect the frame.work charger directly to the SuperTank it pulls close to 50W, but even 15W would be enough to charge it overnight.

@Myles_Dear try charging the bank from the port on the opposite side, leaving the framework charger plugged into the port on the left side.

Thanks, @Shawn_Lewis, that worked! I’m getting 13.3W out to the external battery when I switch sides and have incoming / outgoing USB-C connections on different sides.

I wouldn’t have thought to go there, thanks for the tip.

@Myles_Dear, You’re welcome. The ports are paired on the left and on the right. There are 2 thunderbolt controllers and 1 usb4 controller. When in doubt use the pair on the opposite side.

Regarding a fixed USB-C port… I really would like to have a changable one. That is the reason why i looked for the framework laptop. I have two very active kids and 3 laptops with failed power supply in the last 18 month.

That changeable power adapter would be the reason for me to buy one - but the small size and the glare display is something which I would not buy. So hoping for my standard 17" display in a future generation.

So I need to order one USB-C for charging or else I wont be able to charge it.

Side question, safety wise I am very addicted to my macbook magsafe power connector. (dogs running around and stuff.) wil there be a sort of DIY expansion card available in the future so I can mod the expansion cartrage with a magsafe connector (availible at ali I think) instread of the USB-C?

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@Sean_Greenslade is it still the case that the laptop won’t draw more than 60W? With windows 11 running and charge under 40%, my laptop pulls nearly 100W. Do you have documentation to support this?

@sgt_rjp No, I was mistaken. As reported here, the USB-C ports and power input circuitry are capable of accepting up to 5 A at 20 V, allowing a maximum of 100 W of input (assuming your USB-C charger supports that voltage and current).

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