Hacker News Reader

Comment by Forge36 | Hacker News Reader

I know at some point I'm sure I asked for fewer connector types. Seeing it now: I suspect unique connectors to a purpose is insanely useful usability. Immediate failure feedback has it's uses.

See NEMA outlet variation [1].

[1]https://en.wikipedia.org/wiki/NEMA_connector#/media/File:NEM...

View on HN

I recently received a new work laptop in the mail. And IT had stuck a piece of paper inside explaining it is essential I only charge it with the charger it came with, other usb-c chargers/cables might not work and could possibly damage the laptop. I am very ignorant on usb-c, but to me it seems crazy it's come to things like that.

How true is it?

Off brand chargers are probably more of a concern than the actual cable. There are some really shoddy ones out there.

Not very, barring some ridiculous chinese knock-offs. Normally low power cable wouldn't be able to negotiate more power than what it is rated for.

Not working? Totally true.

Damaging it? There's definitely historical evidence for it [1], but I think the situation is a little improved these days. I personally had a nexus 5x charger damage a Pixel 3a such that that charger and usb a-c cables were the only ones which would work in that device from then on.

[1]: https://www.engadget.com/2016-02-03-benson-leung-chromebook-...

I had a pixel 3a melt its own charging port, drawing too much power from an aftermarket usb hub

Fwiw, I have been charging my Pixel 3aXL with my Nexus 5X charger every night since I got the 3aXL a year and a half ago without issue.

You can charge with any cable that supports that power level. The problem is you can buy cheap cables that don't meet standards and can burn up. Or, the laptop won't charge at all because the user's own charger doesn't support Power Delivery, and IT doesn't want to deal with supporting 3rd party chargers—I know my Dell XPS 13 won't charge over normal USB at all, and needs a 45W charger to charge at full speed.

Lots of Nintendo Switch charger/dock anecdotes revealing issues here.

Most of the anecdotes revolve around a specific faulty dock whose manufacturer thought it were a brilliant idea to implement PD with a microcontroller that used 9V signalling level, whereas the (standard compliant!) Switch PD chip expected 5V (with 6V max) and as a result, the dock fried the Switch's PD chip.

Also, the Nintendo Switch Dock's male USB-C plug is a tiny bit more narrow to provide a smooth slide in/out (and the Switch-side female receptacle is standard-conforming)... un-licensed and thus unaware dock vendors cluelessly tried to emulate that and botched the tolerances, exposing the CC pins to 15V.

See https://arstechnica.com/gaming/2019/08/heres-why-nintendo-sw... for more.

tl;dr: the Switch is standards-compliant, the problem are third party accessories.

My own work laptop is a bit old and has a barrel plug and USB-C. When the laptop is truly out of juice, only the barrel plug will charge it. So I can't leave it at work. YMMV.

Not at all - its likely they wanted to reduce support calls from people who try and charge the laptop using mobile phone and other inappropriate chargers.

I use dell, Lenovo, & apple PD chargers interchangeably without issues.

You can charge a laptop with a mobile phone charger. It just charges really really slowly (or probably not at all if you're actually using it).

Depends on the charger and on the laptop whether that works.

i could not charge my late 2016 pro with my huawei charger (45w)

The 2016 model will charge in sleep mode on a 30w charger, it's just glacially slow, 2-3% per hour at best. 65W seems to be the universal standard for day-to-day use with laptops.

Generally it has to be usb-pd and 45W or more in my experience.

I think that piece of paper spreading FUD is a simple attempt by the IT department to minimize the number of people trying to charge their laptop off of an 10-18w cell phone charger and generating charging failure tickets in the system

Dell famously won't charge off anything less than 65w USB-C PD when turned on, and I think 30w when turned off. Apple will trickle charge when off, on 15w (standard phone charger) if the charger truly is USB-C PD compliant (about 50% of the time these days)

Given that most people don't own a 65W USB-C PD charger (yet) I can see the IT department adding warnings in an attempt to avoid confusion and reduce the amount of extra work.

That said, I've been using USB-C 65W chargers since the original Pixelbook came out + Nexus 5, and later Anker branded 65W chargers and I've never had any problems. I generally don't use off brand stuff though.

Not common, but there are models more susceptible to issues than others. For example I've got a Lenovo Yoga which breaks when connected to an apple charger. The touchpad starts to misbehave and if you put it to sleep, it won't wake up until you disconnect the charger. (no long term damage though as far as I can tell) OnePlus 6 phone behaves correctly, but gets much hotter with the apple charger than with its own / google nexus / lenovo.

The Nintendo Switch famously has this problem on third-party USB-C docks

I burned out my XPS 15 USB-C charging electronics by using a high-end charger. I think many laptops of a certain age were not rigorously tested for USB charging. Hopefully that's changing.

Bad USB-C cables and hubs could brick M1 Macbooks as recently as February of this year before Apple issued an update.

I wish laptops would've standardised on the 20V barrel jack (maybe with slightly different sizes to denote current capability), like they almost did before USB-C came along.

What's the advantage of that over usb-pd chargers that also deliver 20V?

That there aren't as many 5-12v ones that you can accidentally use in place of it?

That there aren't a bunch of cables which _might_ work, not to be confused with the same cables that carry data.

Yeah but usb-c is safe - if its not the right protocol it just defaults to 5v and nothing gets damaged.

Barrel connectors of wrong voltage and/or polarity will let out the magic smoke.

A much simpler and more robust interface.

With USB-C charger, I can charge my:

- ANC Headphones

- Laptop

- Tablet

- Phone

- Portable in-ear headphones

and bunch of other stuff I carry around while traveling. All of those with a single 100W laptop charger.

I can't do that with a barrel connector. It's a huge improvement despite "confusion" everyone on this site loves harping on.

I'd be very cool with a charging standard that included the needed info.

20v/140w :: 12v/80w etc;

and a different connector for _data_ with similar markings for

40G/20G/10G/5G/480Mb

Yeah, IMO the issue is really information - ports, cables and chargers should have a clear information about how much power and which data can be delivered.

"maybe with slightly different sizes to denote current capability"

That's what we had - 10 invonpatiable barrel-jack charging connectors. At a friend's place and want to use his charge? Tough luck. Congratulations.

Why do you need supplies with different current to be incompatiable?

In a 20V DC barrel jack case, so you don’t plug in a device with 4 ohms of resistance to a $2.99 charger spec’d (and only capable) to only deliver 20W of power. (Realistically, not every one of those chargers will have a current limiting supply inside.)

I think you've rebutted your own point there, laptops cost hunders or thousands, whats with $2.99 power supply? You spill coffee on the laptop and the power brick burns your house down?

I shorted many laptop power supplies while using them to test LED's strips, all of them seemed to have current limiting.

I don't think that the only (or even most common) source of power supplies in people's houses are from the OEMs of laptops.

In an alternative timeline where DC barrel jacks were the standard form factor, you'd have just as many sellers of the cheapest possible power supply in that form factor as you do in the USB-A form factor today. Engineering choices have to take into account the reasonably foreseeable uses and misuses of a design. In this case, having current relating to the barrel diameter seems reasonable. (A phone might prioritize thin-ness and doesn't need a lot of power. A 100W piece of desktop/benchtop gear or a laptop can better afford the increased diameter of the higher current supply. Not to mention that it gives a somewhat intuitive sense to non-engineers.)

'In an alternative timeline where DC barrel jacks were the standard... having current relating to the barrel diameter seems reasonable.'

There are too many possible variations, I have 6 devices in my house, and their power supplies are 130W, 65W, 45W, 25W, 18W and 10W. You would have waay to many barel diameters. The key benefit is using a larger power supply to charge smaller device.

If you want a standard that is usable, you have to have features like current limiting

For the purpose of power delivery this makes sense, but for the purpose of sending data down a wire, most people’s use cases can be done with the throughput of most usb-c cables, it is really convenient to just use any cable lying around for any data usage.

It was a missed opportunity to decouple power delivery from data link at the port through a visible, mechanical design like maybe a two-part connector. That way the data-only portion should always work as long as you've got a proper cable.

The NEMA code is exactly what I think about when I think about USB-C's failures. Imagine if NEMA connectors were standardized and the voltage/amperage was disconnected from the shape of the connector? Ridiculous.

While a standardized USB-C connector with non-standardized features isn't that dangerous, it's equally stupid, and was solved decades ago.

1) NEMA connectors cannot signal how much voltage/power they can handle though. If they could, there would be more pressure to use a single connector

2) You absolutely can plug the wrong IEC13/14 cable in to incompatible devices, or pass more capacity than it's rated for. For example, I've seen equipment with IEC14 sockets that only takes 120V (not SMPS), nothing stopping you from plugging in a UK240xIEC13 and letting some angry pixies loose.

Is that IEC compliant usage? Who knows, but it's convenient so manufacturers do it anyways.

Reply on news.ycombinator.com