this post was submitted on 06 Sep 2025
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So I have an L390 Yoga with USB-C charging. Original adapter works at full speed. I got a 45W power bank, works at full speed.

But that was just a coincidence.

I already tried 5 other adapters and all can only charge it at 10W with 5V. 3 were 22.5W, so maybe, but now I got a 45W GaN adapter, with the same 20V 2.25A as the power bank, yet again just 10W. It even has PPS.
I also tried a 66W adapter I have, with 20V 3.25A mode, 10W again.

The only 3rd party thing that works is Choetech B653 power bank.

I have also tried 2 different cables, one of which is rated at 120W, but both only work with the power bank.

So what am I missing? Or is it just some Lenovo BS to make you use official adapter?

Like this it's faster to charge the power bank, and then the laptop from it.

Edit: Switches to 20V when I connect something to USB-A on the adapter, but keeps turning off and on repeatedly (the adapter).

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[–] IcedRaktajino@startrek.website 5 points 2 days ago* (last edited 2 days ago) (1 children)

Maybe just that model? I've got an X1 carbon. It expects 45W and will run from anything that spits out 20V. Even hooked it into a 20W power bank. It complained that the supply was below expectations and that the battery might not charge but it worked.

[–] user224@lemmy.sdf.org 1 points 2 days ago

Hmmm, it does switch to 20V when something is connected to the adapters USB-A, but will keep restarting (the adapter).

[–] damnthefilibuster@lemmy.world 2 points 2 days ago

Probably an Apple like chip to check the originality of the charging solution you’re connecting to it. Everything else is treated as a “bad idea” or something.