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Can I charge a 19V laptop from multiple USB ports? (ma.fellr.net)

submitted 2 months ago by [email protected] to c/[email protected]

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Can I charge a 19V laptop from multiple USB ports?

My laptop's charger is rated at 19V 2.1A. I was wondering if it would be possible to build an adapter which would allow me to charge it from a power bank, even if just slowly or via multiple USB ports.

I know you can buy adapters which utilise USB power delivery, but most outlets and powerbanks don't have PD yet.

@askelectronics #AskFedi #Electronics #DIY #USB

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[–] madnificent 3 points 2 months ago (2 children)

I have done this using a usbc power bank explicitly rated to 20v. You only need a usbc power delivery trigger (which are not expensive).

I used diodes from a washing machine to drop from 20v to about 18.8v in my case. These dissipate quite a bit of heat so my cable has an extra metal plate as heatsink. I would put the diodes in the middle of the cable if I'd make it again. It is good for keeping it topped up as the current is lower and the heat stays lower too.

[–] [email protected] 2 points 2 months ago (1 children)

If your powerbank has full power delivery support(it probably doesnt) then you can request voltages in 1/10v increments. This is very cool but you need a chip that communicates in your cable.

[–] madnificent 1 points 2 months ago

I totally forgot about that :P That would be great indeed.

The PD trigger board may be much more involved/expensive though and I have not seen any budget battery banks supporting it. One can dream.

I expect consuming devices to adapt themselves to the three or four commonly provided voltages for the foreseeable future.