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   OpenComputeDesign (opencomputedesign@linuxrocks.online)'s status on Tuesday, 03-Jun-2025 11:36:04 JST OpenComputeDesign

   @rl_dane @mirabilos In theory a USB-C PD pack should be able to output 20v

   In practice USB-C PD has never worked for _me_ but I'm very old fashioned in my ways and don't play well with modern things generally, so :P

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     翠星石 (suiseiseki@freesoftwareextremist.com)'s status on Tuesday, 03-Jun-2025 11:36:03 JST 翠星石

     in reply to
     @OpenComputeDesign @rl_dane @mirabilos If they even exist, a 20V USB-C PD pack will not do, as USB-C defaults to 5V at a handful of mA until a handshake is done for full 5V and then a handshake for 20V.
     
     There are re-programmable USB-C PD to barrel jack adaptors for 5V/7V/9V/10V/12V/15V/20V, but I cannot recommend any, as they are designed to be programmed by loading proprietary software only on windows - but those are only advertised to work with wall plugs (I suspect that 20V USB-C PD battery packs don't exist or are extremely uncommon, considering that most Li-Ion cells are 3.6-3.7V nominal and the typical configuration targets ~10V - thus outputting more than than 9V would generally need a built-in boost convertor - 5V-10V/12V boost convertors are common, but 5V-10V/20V are not).
     
     You'll need to solder up a custom voltage convertor, or make a PCB for a custom battery, but if you are doing that, you may as well make a PCB for a custom battery with a microcontroller that runs free software instead (and get battery percentage reporting too).
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     翠星石 (suiseiseki@freesoftwareextremist.com)'s status on Tuesday, 03-Jun-2025 11:45:03 JST 翠星石

     in reply to
     @OpenComputeDesign @rl_dane @mirabilos Ah yes, there is also the problem if the pack can provide enough amps either (which is another reason why 20V packs probably aren't a thing - even Li-Ion doesn't pack enough amps to need 20V unless you are using a big heavy battery with many cells).
     
     If you bypassed the amp regulation it would probably work for a few minutes before deflagrating :3
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     OpenComputeDesign (opencomputedesign@linuxrocks.online)'s status on Tuesday, 03-Jun-2025 11:45:04 JST OpenComputeDesign

     in reply to

     • 翠星石

     @Suiseiseki @rl_dane @mirabilos

     I did once have a USB battery bank that could output 12v, that I did try to use to run a laptop that could run on 12v. Unfortunately it needed twice the amps the pack could provide, much to my disappointment in realizing that the stated max discharge per port was actually for both ports as well (so one port could provide the full power, or both ports half power) negating my "hack" of using both ports.