Groups | Search | Server Info | Login | Register

Groups > alt.comp.hardware > #20754

Re: Universal power supply for PCs, setting voltage

Cross-posted to 2 groups.

Show all headers | View raw

In sci.electronics.repair, on Sun, 30 Mar 2025 13:01:25 -0400, Paul
<nospam@needed.invalid> wrote:

>On Sun, 3/30/2025 11:55 AM, micky wrote:
>> I probably don't need a universal auto power supply, but otoh, if I'd
>> bought one for the last laptop, I wouldn't to spend 30 or so dollars for
>> another one now. 
>> 
>> Some of them have 3 wires connecting the tips, one to tell the power
>> supply what voltage to provide, I assume, but others have only 2.  How
>> can that be satisfactory. 
>> 
>> This one, for example.  
>> https://www.amazon.com/HKY-Universal-Notebook-Computer-Smartphone/dp/B0BZGSMLMP/ref=sr_1_1_sspa
>> See the first picture.  But it's $44, one of the most expensive.  How
>> could it not work right? 
>> 
>> 
>> 
>> https://www.amazon.com/Belker-Universal-Adapter-Charger-Toshiba/dp/B08LKXDBX3/ref=sr_1_1_sspa
>> Smaller than most.  Are they just trying to trade off the name Belkin? 
>> 
>> At first I thought it had to be good because it was Belker, but when
>> writing this post, I remembered that it's Belkin that has a reputation,
>> not Belker.  !!  
>> 
>> 2)  Some have 50W, 65W or even 100W.   What could need 100W?   I
>> currently have a Dell Latituded 5510 (not the other Dell 5510).  Surely
>> 65 w is enough or even 50. ????
>> 
>
>  Car 12VDC ----------- DC-DC converter ----- USBPD ---+---- USBC output (uses USBPD protocol)
>  Lighter Socket?                                      |                 (for USB port charge)
>                                                       |
>                                                       +--- dumb charging, fixed voltage,
>                                                            barrel adapter
>
>I don't know if the adapter works in those rental cars
>with the plastic cover.

I only wanted that to charge my phone.  Had a hotel and used the
computer there. 

But when I do foreign travel, even if I have rented a room, it can be
too far to drive back at night just to return the next morning, so i
often sleep in the car, and use the laptop before sleeping and in the
morning.  (ne time I used while driving it to find a particular stream
in a "park" and I got interested in having GPS for the laptop, but none
of them had iirc very good reviews and now I can't remmeber why the
phone wasn't good enough anyhow.)  

But I will make sure any rental car in the future has a cigarette
lighter. or power port and young'ns call them. 
>
>The USB PD output option is likely safe.
>The charging speed will be a function of whether
>the laptop even has USB PD protocol. If the adapter were to output
>5V @ 1A for example, the laptop will use a boost converter
>inside, to charge a 14.4V battery pack. If a higher USB PD
>voltage can be negotiated, it might take only
>a buck (down) converter inside the laptop, to charge the battery.
>
>For legacy laptops, this kit proposes to charge
>via a barrel jack. Does it actually output the correct
>voltage ? I would be concerned about that. There was
>evidence previously, that the voltage uncertainty on barrel
>charging was fairly small (even though from an engineering
>perspective, it's not necessary for that voltage to be
>all that tight). I would still be a bit nervous about
>barrel charging, unless the product had a way of selecting
>18.5V, 19V, 20V, or whatever the listed spec for the

The first one I listed above had none. 

>laptop is. I do not want to recommend solutions to people,
>that only burn out the charge management in a laptop a month
>later. That's what happened in at least one case here.
>That was the anecdotal evidence, that a mismatch on
>barrel voltage, put something under stress. Someone visiting
>had a shit eating grin on their face, over the "universal"
>product they bought. A month later they wrote back to say
>the laptop would no longer charge, with anything.
>
>If you have a USB PD laptop, go for it. Otherwise, do not.

Okay. 

>H11: 16V 4A 6.5*4.5mm 19.5v 3.3a 4.7a 6.5*4.4mm
>     So the barrel adapter H11 works with both a 16V laptop
>     and a 19.5V laptop ??? Most of the other barrel tips are playing
>     the close enough game, when they might not be close enough.
>     It could just be using a fixed 19V output when the USB PD
>     protocol is not detected. The advert is pleasantly unclear
>     on the matter.
>
>   Paul

Back to alt.comp.hardware | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Universal power supply for PCs, setting voltage micky <NONONOmisc07@fmguy.com> - 2025-03-30 11:55 -0400
  Re: Universal power supply for PCs, setting voltage hubops@ccanoemail.com - 2025-03-30 12:38 -0400
  Re: Universal power supply for PCs, setting voltage Paul <nospam@needed.invalid> - 2025-03-30 13:01 -0400
    Re: Universal power supply for PCs, setting voltage micky <NONONOmisc07@fmguy.com> - 2025-04-01 10:40 -0400
      Re: Universal power supply for PCs, setting voltage Paul <nospam@needed.invalid> - 2025-04-01 11:54 -0400
        Re: Universal power supply for PCs, setting voltage Allodoxaphobia <trepidation@example.net> - 2025-04-01 18:38 +0000
        Re: Universal power supply for PCs, setting voltage micky <NONONOmisc07@fmguy.com> - 2025-04-01 20:23 -0400

csiph-web